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Exam 4 (VPHY 3100)
Exam 4 (VPHY 3100)
813
Physiology
Undergraduate 3
11/17/2020
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Term
some functions of the respiratory system
 Definition
-Ventilation (breathing) -Gas exchange -O2 utilization and CO2 production [image] [image]
Term
how the respiratory system functions for ventilation (breathing)
 Definition
To move air into and out of respiratory system.
[image]
Term
how the respiratory system functions for gas exchange
 Definition
-External respiration
-Internal respiration
-Pressure gradients generate diffusion
[image]
Term
how the respiratory system functions for O2 utilization and CO2 production
 Definition
Cellular respiration
[image]
Term
External respiration
 Definition
gas exchange between air and capillaries in the lungs
[image]
Term
Internal respiration
 Definition
gas exchange between systemic capillaries and tissues of the body
[image]
Term
2 zones in the airway passages
 Definition
-Conducting zone
-respiratory zone
[image]
Term
Conducting zone
 Definition
-Outside the lungs – nasal passages --> pharynx --> epiglottis --> larynx (glottis)
-Inside the lungs – trachea (1) --> bronchus (2 branches) --> bronchiole --> … --> terminal bronchiole
[image]
Term
Respiratory zone
 Definition
Respiratory bronchiole --> … --> alveolar sacs
[image]
Term
diameter, length, number, and area of different parts of the airway
 Definition
[image]
Term
how collapsing of the trachea and the rest of the conducting zone is prevented
 Definition
rings of cartilage around the trachea and bronchi
Term
Functions of the Conducting Zone of the airways
 Definition
-Passage of air
-Warming
-Humidification
-Filtration
-Immune surveillance
[image]
Term
where does the water for humidification in the airway come from?
 Definition
cells in the airway
Term
the role of the mucociliary apparatus
 Definition
removing particulates in the conducting zone
-you wind up either swallowing it or coughing it out
[image]
Term
Functions of the Respiratory Zone
 Definition
-Passage of air
-Gas exchange
-Immune surveillance
[image]
Term
number, size, and shape of alveoli
 Definition
-Total # = ~300 x 106 -0.25 - 0.5 mm in diameter -Total area = 60 - 80 m2 [image]
Term
the 2 types of cells in the alveolar wall
 Definition
-Type I alveolar cells
-Type II alveolar cells
[image]
Term
function of Type I alveolar cells
 Definition
the major lining cells, accounts for 95-97% of total surface area
[image]
Term
function of Type II alveolar cells
 Definition
production of surfactants
[image]
Term
the air-blood barrier
 Definition
-~0.3 μm
-barrier between blood and air that allows gas exchange to occur
[image]
Term
depiction of the net capillaries form over the alveoli
 Definition
[image]
Term
depiction of the air-blood barrier
 Definition
[image]
Term
the Layers of the respiratory membrane:
 Definition
1. Fluid layer with surfactant. (Surfactant coats the inside of the alveolus).
2. Type I alveolar cell membranes.
(3. Narrow interstitial space, if any.)
4. Capillary endothelial cell membranes.
[image]
Term
depiction of the thoracic cavity in its context
 Definition
[image]
Term
Thoracic cavity surrounded by...
 Definition
rib cage (chest wall) and the respiratory muscles.
[image]
Term
Pleural (intra-pleural) space
 Definition
-Thin fluid layer between visceral pleura covering lungs (visceral) and parietal pleura lining thoracic cavity walls.
-*Air-free, potential space --> lungs cling to inside of thorax.
-basically makes the lungs adhere to the thoracic cavity
[image][image]
Term
diaphragm
 Definition
muscle between thoracic & abdominal cavities
[image]
Term
Quiet Inspiration
 Definition
-active process:
1. Contraction of diaphragm --> ↑ thoracic vol vertically
2. Parasternal and external intercostals contract --> raising the ribs --> ↑ thoracic vol laterally (horizontally); makes the rib cage bigger
[image]
Term
external intercostals
 Definition
muscles between the ribs that cause the thoracic cavity to expand horizontally (laterally)
[image]
Term
the 2 types of expiration in breathing
 Definition
-quiet expiration
-forced expiration
[image]
Term
Quiet expiration
 Definition
passive process, relaxation of inspiratory muscles. [image]
Term
Forced expiration
 Definition
active process assisted by the abdominal muscles. [image]
Term
some functions of the respiratory system
 Definition
-Ventilation (breathing) -Gas exchange -O2 utilization and CO2 production [image] [image]
Term
how the respiratory system functions for ventilation (breathing)
 Definition
To move air into and out of respiratory system.
[image]
Term
how the respiratory system functions for gas exchange
 Definition
-External respiration
-Internal respiration
-Pressure gradients generate diffusion
[image]
Term
how the respiratory system functions for O2 utilization and CO2 production
 Definition
Cellular respiration
[image]
Term
External respiration
 Definition
gas exchange between air and capillaries in the lungs
[image]
Term
Internal respiration
 Definition
gas exchange between systemic capillaries and tissues of the body
[image]
Term
2 zones in the airway passages
 Definition
-Conducting zone
-respiratory zone
[image]
Term
Conducting zone
 Definition
-Outside the lungs – nasal passages --> pharynx --> epiglottis --> larynx (glottis)
-Inside the lungs – trachea (1) --> bronchus (2 branches) --> bronchiole --> … --> terminal bronchiole
[image]
Term
Respiratory zone
 Definition
Respiratory bronchiole --> … --> alveolar sacs
[image]
Term
diameter, length, number, and area of different parts of the airway
 Definition
[image]
Term
how collapsing of the trachea and the rest of the conducting zone is prevented
 Definition
rings of cartilage around the trachea and bronchi
Term
Functions of the Conducting Zone of the airways
 Definition
-Passage of air
-Warming
-Humidification
-Filtration
-Immune surveillance
[image]
Term
where does the water for humidification in the airway come from?
 Definition
cells in the airway
Term
the role of the mucociliary apparatus
 Definition
removing particulates in the conducting zone
-you wind up either swallowing it or coughing it out
[image]
Term
Functions of the Respiratory Zone
 Definition
-Passage of air
-Gas exchange
-Immune surveillance
[image]
Term
number, size, and shape of alveoli
 Definition
-Total # = ~300 x 106 -0.25 - 0.5 mm in diameter -Total area = 60 - 80 m2 [image]
Term
the 2 types of cells in the alveolar wall
 Definition
-Type I alveolar cells
-Type II alveolar cells
[image]
Term
function of Type I alveolar cells
 Definition
the major lining cells, accounts for 95-97% of total surface area
[image]
Term
function of Type II alveolar cells
 Definition
production of surfactants
[image]
Term
the air-blood barrier
 Definition
-~0.3 μm
-barrier between blood and air that allows gas exchange to occur
[image]
Term
depiction of the net capillaries form over the alveoli
 Definition
[image]
Term
depiction of the air-blood barrier
 Definition
[image]
Term
the Layers of the respiratory membrane:
 Definition
1. Fluid layer with surfactant. (Surfactant coats the inside of the alveolus).
2. Type I alveolar cell membranes.
(3. Narrow interstitial space, if any.)
4. Capillary endothelial cell membranes.
[image]
Term
depiction of the thoracic cavity in its context
 Definition
[image]
Term
Thoracic cavity surrounded by...
 Definition
rib cage (chest wall) and the respiratory muscles.
[image]
Term
Pleural (intra-pleural) space
 Definition
-Thin fluid layer between visceral pleura covering lungs (visceral) and parietal pleura lining thoracic cavity walls.
-*Air-free, potential space --> lungs cling to inside of thorax.
-basically makes the lungs adhere to the thoracic cavity
[image][image]
Term
diaphragm
 Definition
muscle between thoracic & abdominal cavities
[image]
Term
Quiet Inspiration
 Definition
-active process:
1. Contraction of diaphragm --> ↑ thoracic vol vertically
2. Parasternal and external intercostals contract --> raising the ribs --> ↑ thoracic vol laterally (horizontally); makes the rib cage bigger
[image]
Term
external intercostals
 Definition
muscles between the ribs that cause the thoracic cavity to expand horizontally (laterally)
[image]
Term
the 2 types of expiration in breathing
 Definition
-quiet expiration
-forced expiration
[image]
Term
Quiet expiration
 Definition
passive process, relaxation of inspiratory muscles. [image]
Term
Forced expiration
 Definition
active process assisted by the abdominal muscles. [image]
Term
Boyle's Law
 Definition
-At a constant temperature P1V1 = P2V2
-Thoracic expansion and contraction -> air movement
-pressure and volume have an inverse relationship in the lungs
[image]
Term
How do we get O2 into the body and CO2 out of the body?
 Definition
-Ventilation = air in and out of lungs
-Results from pressure differences (gradient) induced by changes in lung volumes
-Pressure (P) gradient – results in net gas flow & diffusion from high P to low P
[image]
Term
flow of O2 and CO2 in respiration
 Definition
-For PO2 – alveolar space > blood plasma > interstitial fluid > cytosol > mitochondria -For PCO2 – mitochondria > cytosol > interstitial fluid > blood plasma > alveoli -this flow is caused by partial pressures [image]
Term
the 3 pressures to follow in respiration
 Definition
-Atmospheric
-Alveolar (Intrapulmonary)
-Pleural (Intrapleural)
[image]
Term
Atmospheric pressure
 Definition
always 760 mm Hg
[image]
Term
Alveolar (Intrapulmonary) pressure
 Definition
at rest, during inspiration, during expiration
[image]
Term
Pleural (Intrapleural) pressure
 Definition
at rest, during inspiration, during expiration
[image]
Term
the 3 phases of breathing
 Definition
-at rest
-inspiration
-expiration
[image]
Term
the interplay between the recoil of the lungs and the chest wall
 Definition
-The lung tends to recoil inward and the chest wall outward -*These recoil forces in opposite directions create a negative (sub-atmospheric) pleural pressure: -3 to -4 mm Hg relative to atmospheric and alveolar pressures. +-> Lungs expand and contract along with the thoracic cavity. [image]
Term
What happens if the pleural space is disrupted by air or fluid?
 Definition
lungs basically collapse due to the greater pleural space
-Air (pneumothorax) or fluid (hydrothorax, generically) -> relative negative pressure lost -> lung lobes collapse.
-New pressure gradient -> pneumothorax.
[image]
Term
Mediastinum
 Definition
separates each side of thorax; this is why only one lung is affected by the disruption of the pleural space
[image]
Term
Mechanics of Breathing (Ventilation) during inspiration
 Definition
-Contraction of inspiratory muscles --> ↑ chest vol --> ↑ pleural vol --> ↓ pleural P --> ↑ lung vol --> ↓ alveolar P
---> atmospheric P > alveolar P --> generation of pressure gradient --> air to flows into the lung
-Energy -> muscular contraction -> works against the elastic recoil forces of the lung.
Term
Mechanics of Breathing (Ventilation) during expiration
 Definition
-↓ lung vol --> ↑ alveolar pressure above atmosphere (alveolar P > atmospheric P) --> air goes out
-Elastic recoil forces of the lung contribute to change in pressure gradient.
Term
how alveolar and pleural pressure change during inspiration and expiration
 Definition
[image]
Term
Pleural Pressure
 Definition
ALWAYS lower than alveolar P & atmospheric P
-ALWAYS negative (sub-atmospheric)
Term
Alveolar Pressure
 Definition
may be “-” (inspiration) or “+” (expiration)
Term
Trans-pulmonary Pressure
 Definition
Trans-pulmonary P = Δ P across the wall of the lung
Δ P across the wall of the lung = Alveolar P – Pleural P
-Always positive
-Increasing difference vs. decreasing difference.
Term
types of lung volumes
 Definition
-tidal vol (TV)
-inspiratory reserve vol (IRV)
-expiratory reserve vol (ERV)
-residual vol (RV)
[image]
Term
types of lung capacities
 Definition
-inspiratory capacity (IC)
-functional residual capacity (FRC)
-vital capacity (VC)
-total lung capacity (TLC)
[image]
Term
Timed vital capacity (or forced expiration volume for the 1st second, FEV1)
 Definition
normal is > 80%
-this is the amount of air you can force out of your lungs within the first second of a forceful breath out
-can be used to assess lung function
[image]
Term
total volume
 Definition
the volume of gas inspired or expired in an unforced respiratory cycle at rest
[image]
Term
residual volume
 Definition
the volume of gas remaining in the lungs after a maximum expiration
[image]
Term
total lung capacity
 Definition
the total amount of gas in the lungs after a maximum inspiration
[image]
Term
vital capacity
 Definition
the maximum amount of gas that can be expired after a maximum inspiration
[image]
Term
Dead space
 Definition
regions of the airways that are ventilated but no gas exchange occurs
[image]
Term
Physiologic dead space
 Definition
anatomic dead space + alveolar dead space
[image]
Term
Anatomic dead space
 Definition
-*Air in the conducting airways of respiratory system that does NOT participate in the gas exchange. -Not all of the inspired air reaches the alveoli. -Inhaled fresh air mixed with expired air in anatomical dead space. [image]
Term
Alveolar or functional dead space
 Definition
-*Air in the respiratory zone that is ventilated but does NOT participate in gas exchange.
-Due to lack of blood flow to those alveoli.
[image]
Term
Ventilation-Perfusion Ratio (V/Q)
 Definition
-VA = alveolar ventilation -Q = blood flow -For efficient gas exchange (O2 in, CO2 out), want level of ventilation to match blood flow in alveoli. V/Q ≈ 0.8 -VA is greater in the apices of the lungs -> high V/Q – overventilated and underperfused -Q is greater in the basal lung lobes -> low V/Q – underventilated and overperfused [image]
Term
the part of the lungs that is overventilated and underperfused and why that is
 Definition
VA is greater in the apices of the lungs -> high V/Q – overventilated and underperfused [image]
Term
the part of the lungs that is underventilated and overperfused and why that is
 Definition
Q is greater in the basal lung lobes -> low V/Q – underventilated and overperfused
[image]
Term
ideal Ventilation-Perfusion Ratio (V/Q)
 Definition
0.8 -For efficient gas exchange (O2 in, CO2 out), want level of ventilation to match blood flow in alveoli.
Term
why putting COVID-19 patients on their sternum helps them breathe
 Definition
because it helps open up some lung space on the dorsal side
Term
what Systemic arterioles (e.g., muscle beds) do in response to low arterial O2 levels (PaO2)
 Definition
they dilate if arterial O2 levels (PaO2) are low -> more blood with O2 delivered.
Term
what Pulmonary arterioles do in response to alveolar O2 (PAO2) levels
 Definition
they constrict if alveolar O2 levels (PAO2) are low. Dilate if PAO2 high. [image]
Term
the factors affecting ventilation
 Definition
-compliance
-elastance (elasticity)
-surface tension
Term
Compliance
 Definition
distensibility (stretchability)
-Change in lung vol per change in transpulmonary P
+Compliance = ΔV/ΔP
-100 x more distensible than a balloon
-Compliance is affected by elastance (2) ; and surface tension (3)
Term
Elastance (elasticity)
 Definition
recoil ability, resistance to distension
-Elasticity = 1/compliance
-Tendency to return to initial size after distension.
-High content of elastin proteins
-Elastic tension ↑ during inspiration and ↓ during expiration
Term
Compliance is affected by...
 Definition
-elastance
-surface tension
Term
Compliance = ...
 Definition
Compliance = ΔV/ΔP
Term
elasticity = ...
 Definition
1 / compliance
Term
Surface tension (T)
 Definition
Reflects the work needed to ↑ surface area of a liquid at an interface.
[image]
Term
Law of Laplace
 Definition
P in alveoli is directly proportional to surface tension; and inversely proportional to radius of alveoli.
-T is the same for same interface.
-For the same T, smaller alveoli have higher P to collapse than larger alveoli.
-r=2 (P=T) vs. r=1 (P=2T) --> collapse of smaller alveoli
-↑ P --> ↓ compliance --> takes more energy to expand.
[image]
Term
equation for the Law of Laplace
 Definition
P = (2 x T) / r
where P = pressure, T = surface tension, and r = radius
[image]
Term
surfactants in the lungs
 Definition
-Produced by type II alveolar cells (pneumocytes).
1. Phospholipids – amphipathic; act as surfactant
2. Surfactant proteins – help distribute phospholipids.
[image]
Term
functions of surfactants in the lungs
 Definition
-Lower surface tension --> ↑ compliance.
-Prevent collapse of smaller alveoli.
+As alveoli radius decreases, surfactant’s ability to lower surface tension increases.
Term
Newborn respiratory distress syndrome
 Definition
-Occurs in ~10% of premature neonates.
-Underdeveloped anatomy.
-Surfactant insufficiency; not enough surfactant and thus less compliance, making it harder to breathe.
-Every breath is like the first breath.
[image][image]
Term
how the alveoli in Newborn respiratory distress syndrome differ from those in healthy newborns
 Definition
[image]
Term
some ways Newborn respiratory distress syndrome can be treated
 Definition
-administering surfactants endotrachially
-corticosteroids; stimulate development of type I and type II pneumocytes
Term
Restrictive Disorders (breathing)
 Definition
-Ex., pulmonary fibrosis -Accumulation of fibrous connective tissue in alveolar wall. -↓ vital capacity; normal FEV1; ↓ compliance -*Reduced lung volume [image]
Term
examples of restrictive pulmonary disorders
 Definition
pulmonary fibrosis
Term
the phase of breathing affected by restrictive disorders
 Definition
inspiration
Term
Obstructive Disorders (breathing)
 Definition
-Ex., asthma, cystic fibrosis -Vital capacity may be normal; FEV1 is < 80% -*Reduced airflow [image][image]
Term
examples of pulmonary Obstructive Disorders
 Definition
-asthma
-cystic fibrosis
Term
the phase of breathing affected by obstructive disorders
 Definition
expiration
Term
Emphysema
 Definition
-alveolar tissue is destroyed,  compliance
-Chronic progressive; reduces surface area for gas exchange
-Cigarette smoking --> ↑ WBC proteinases secretion --> ↑ destruction tissue proteins ↑ collapse of alveolar sacs
[image]
Term
COPD
 Definition
chronic obstructive pulmonary disease
-Asthma & emphysema
Term
Dalton’s Law
 Definition
the law of partial pressures -The pressure exerted by each component in a gaseous mixture is independent of other gases in the mixture, and the total pressure of the mixture of gases is equal to the sum of the separate pressures. -PB = PCO2 + PO2 + PN2 + PH2O = 760 mm Hg atmospheric pressure (PB = barometric pressure -Movement of individual gases
Term
Henry’s Law
 Definition
C = kP
-Concentration of gas in liquid = solubility x partial pressure in liquid.
-At equilibrium, partial pressure is equal on both gas and liquid sides, but # of molecules varies depending on solubility of the gas.
[image]
Term
equation for Henry's law
 Definition
C = kP

Concentration of gas in liquid (C) = solubility (k) x partial pressure in liquid (P)
Term
liquid phase of gases
 Definition
dissolved in blood plasma
Term
depiction of how partial pressures dictate the movement of O2 and CO2
 Definition
[image] PA = partial pressure alveolar Pa = partial pressure arterial Pv = partial pressure venous
Term
blood flow rate in pulmonary vs. systemic circulation
 Definition
Rate of blood flow through the pulmonary circulation = flow rate through the systemic circulation

that is, the amount of blood entering the pulmonary circulation is equal to the amount of blood entering the systemic circulation
Term
depiction of the path blood takes from the tissues --> right heart --> lungs --> left heart --> tissues
 Definition
[image]
Please know the path of blood through the heart, lungs, and systemic circulation.
Term
why Pulmonary vascular resistance is lower than systemic vascular resistance
 Definition
because of less smooth muscle in the pulmonary vessels

this may be to prevent rupture of vessels in the lungs
Term
the pressure gradient for O2 is 64, but the one for CO2 is only 5, so why does it work?
 Definition
because CO2 has a much higher diffusion rate in fluid/tissue phase vs. O2 Solubility coefficient CO2/solubility coefficient O2 = 0.57/0.024 = 23.75/1 -Need a much higher diffusion gradient for O2 to supply enough molecules to tissues to produce ATP. -Much lower diffusion gradient for CO2 needed to bring enough molecules to lung for exhalation.
Term
where the O2 is in the blood
 Definition
-Dissolved O2 (< 2%) -Hb-O2 (> 98%)
Term
amount of hemoglobin in red blood cells and how much O2 they carry
 Definition
280 million Hb/Red Blood Cell -Each Hb has 4 polypeptide chains (2 alpha, 2 beta) and 4 hemes -*1 heme binds to 1 O2, thus 1 Hb binds to 4 O2 maximally [image]
Term
Anemia
 Definition
↓ RBCs -> [Hb] below normal
Term
Polycythemia
 Definition
↑ RBCs -> [Hb] above normal
Term
erythropoietin
 Definition
controls Hb production -Production stimulated by PCO2 delivery to kidneys
Term
some types of hemoglobin associated with health problems
 Definition
-Methemoglobin
-Carboxyhemoglobin
Term
Methemoglobin
 Definition
Fe2+ oxidized -> Fe3+, cannot bind with O2 -Brown blood, brownish-blue mucous membranes -this can be caused by nitrates and other substances that can oxidize hemoglobin -can be treated by reducing agents such as methylene blue and ascorbic acid
Term
Carboxyhemoglobin
 Definition
(CO-Hb) – carbon monoxide. -The bond with CO is 210x stronger than the bond with O2. -Transport of O2 to tissues is impaired. -the CO can't be used for oxidative phosphorylation
Term
Hb-O2 Dissociation Curve
 Definition
[image] -X-axis denotes PO2 (mm Hg) -Y-axis denotes O2 saturation rate (%) or O2 content (mL O2 /dL blood) -The higher the PO2, the higher Hb-O2 saturation
Term
the pathway by which O2 is loaded onto hemoglobin and the saturation it reaches
 Definition
Gas exchange at alveolar space → loading of O2 → oxygenated blood → PO2 = 100 mm Hg → O2-Hb is ~98% [image]
Term
the pathway by which O2 is unloaded off of hemoglobin and the saturation it reaches
 Definition
At peripheral tissues → unloading of O2 → deoxygenated blood → PO2 = to 40 mm Hg → O2-Hb is ~ 75% [image]
Term
why muscles use myoglobin
 Definition
to maintain a steady O2 supply
Term
depiction of the cooperative binding of hemoglobin to O2 and how it changes affinity to O2
 Definition
[image][image]
Term
the Hb-O2 Curve shifting to the left indicates...
 Definition
increased affinity of Hb for O2 [image]
Term
the Hb-O2 Curve shifting to the right indicates...
 Definition
decreased affinity of Hb for O2 [image]
Term
what increased affinity of hemoglobin to O2 means in the lungs and tissues
 Definition
-for the lungs, it means loading a little more O2 onto the hemoglobin -for the tissues, it means more O2 remains on the hemoglobin in the tissues [image]
Term
what decreased affinity of hemoglobin to O2 means in the lungs and tissues
 Definition
-for the lungs, it means a little less O2 being loaded onto the hemoglobin -for the tissues, it means a lot more O2 unloaded in the tissues [image]
Term
when the Hb-O2 curve shifts to the right
 Definition
when there's more need for O2 in the tissues [image]
Term
some factors that cause the Hb-O2 curve to shift to the right
 Definition
-↓ pH (acidosis) → right shift -↑ PCO2 (suggests hypoxemia) → right shift (Bohr effect) -↑ temperature → right shift -↑ [2,3-DPG] in RBC → right shift [image]
Term
some factors that cause the Hb-O2 curve to shift to the left
 Definition
-↑ pH (alkalosis) → left shift -↓ PCO2 (suggests hypoxemia) → left shift (Bohr effect) -↓ temperature → left shift -↓ [2,3-DPG] in RBC → left shift [image]
Term
2,3-diphosphoglycerate or 2,3 bisphosphoglycerate (2,3-BPG)
 Definition
-Metabolic by-product of glycolysis in RBCs.
-O2 inhibits its production.
-2,3-DPG binds Hb -> decrease in affinity for O2 -> right shift where more O2 is released in tissues.
-2,3-DPG production ↑ with hypoxemic conditions
+Anemia
+High altitudes
+Some forms of chronic lung disease
[image]
Term
how 2,3-DPG causes right shift in the Hb-O2 curve
 Definition
2,3-DPG binds Hb -> decrease in affinity for O2 -> right shift where more O2 is released in tissues [image]
Term
some hypoxemic conditions that cause ↑ 2,3-DPG production
 Definition
-Anemia
-High altitudes
-Some forms of chronic lung disease
Term
Muscle Myoglobin
 Definition
-Red pigment found exclusively in striated muscle (skeletal and cardiac muscle fibers). -*Has a higher affinity for O2 than Hb. [image]
Term
what myoglobin does in muscles
 Definition
-Ferrying effect – acts as a “go-between” in the transfer of O2 from blood to the mitochondria within muscle cells. -O2 storage function – in cardiac muscles.
Term
Normal blood pH
 Definition
7.40 (7.35 – 7.45)
Term
Acidosis
 Definition
pH < 7.35 ↑ H+ ions
Term
Alkalosis
 Definition
pH > 7.45 ↓ H+ ions
Term
2 major classes of acids in body
 Definition
-volatile acid
-non-volatile acid
Term
volatile acid
 Definition
can be converted to a gas -CO2 in bicarbonate buffer system can be breathed out (lungs).
Term
Non-volatile acids
 Definition
cannot leave blood
-lactic acid, fatty acids, ketone bodies
-Need to bind to buffer molecules
Term
examples of volatile acids in the blood
 Definition
CO2 in bicarbonate buffer system can be breathed out (lungs).
Term
examples of non-volatile acids in the blood
 Definition
-lactic acid
-fatty acids
-ketone bodies
-Need to bind to buffer molecules
Term
Buffers in the body for non-volatile acids include...
 Definition
-HCO3– -PO42– -proteins including Hb
Term
how kidneys help regulate blood pH
 Definition
-excrete H+ into urine -reabsorb HCO3- from urine
Term
the formula for the bicarbonate buffer system
 Definition
CO2 + H2O ⇌ H2CO3 ⇌ H+ + HCO3- [image]
Term
the bicarbonate buffer system the blood uses
 Definition
[image]
Term
carbonic anhydrase enzyme (CA)
 Definition
-Catalyzes reaction both directions.
-Higher expression in RBCs, gastric mucosa, pancreatic exocrine cells, renal tubules.
[image]
Term
Henderson-Hasselbalch equation relating to blood
 Definition
pH = 6.1 + log ( [HCO3-] / [CO2] )
Term
[CO2] is adjusted by ______, [HCO3-] by kidneys
 Definition
lungs
kidneys
Term
Free H+ in ______ concentrations, free HCO3- in mmol/L concentrations.
 Definition
nmol/L
mmol/L
Term
What effect does adding HCO3- have on plasma [H+]?
 Definition
decreases it
[image]
Term
What does increased [HCO3-] do to pH?
 Definition
raises it
[image]
Term
What does decreased [HCO3-] do to pH?
 Definition
lowers it
[image]
Term
What effect does adding CO2 have on plasma [H+]?
 Definition
increases it
[image]
Term
What does increased [CO2] do to pH?
 Definition
lowers it
[image]
Term
What does decreased [CO2] do to pH?
 Definition
raises it
[image]
Term
what ventilation adjusts itself to and why
 Definition
Ventilation usually adjusted to metabolic rate to maintain normal CO2 levels.
Term
So how would the lungs (controlled by the brain) respond to ↑ plasma [CO2], ↑ plasma [H+], and ↓ plasma pH?
 Definition
increase breathing rate to release CO2 and bring the pH back into balance [image]
Term
And how would the lungs (controlled by the brain) respond to ↓ plasma [CO2], ↓ plasma [H+], and ↑ plasma pH?
 Definition
decrease breathing rate to retain CO2 and bring the pH back into balance [image]
Term
Respiratory acidosis
 Definition
-Caused by hypoventilation, which can be caused by CNS depression, neuromuscular disorders, chest wall restriction, pulmonary tissue disease, airway obstruction. -Accumulation of CO2 in the tissues --> ↑ PCO2 in blood --> ↓ pH in blood
Term
Respiratory alkalosis
 Definition
-Caused by hyperventilation, which can be caused by CNS disease, acute asthma, hypoxemia. -Excessive loss of CO2 --> ↓ PCO2 --> ↑ pH in blood
Term
3 forms of CO2 that are transported in the blood
 Definition
-Dissolved CO2 (10%) – accounts for PCO2 -HCO3- (70%) -Carbaminohemoglobin (20%) +Unloading of O2 --> Hb-CO2 formed +CO2 does NOT bind heme in Hb.
Term
does CO2 bind the heme in hemoglobin?
 Definition
no
Term
how Carbaminohemoglobin is formed
 Definition
Unloading of O2 --> Hb-CO2 formed [image]
Term
Carbonic anhydrase is located in...
 Definition
RBCs
Term
how bicarbonate (HCO3-) gets transported across the plasma membrane of red blood cells
 Definition
Antiporter exchanges chloride (Cl-) for bicarbonate (HCO3-). [image]
Term
carbaminohemoglobin
 Definition
hemoglobin with CO2 bound to one of the amino acids
Term
how Cl-/HCO3- exchange differs systemic capillaries and pulmonary capillaries
 Definition
Cl- goes into the red blood cell in the systemic capillaries and out of the red blood cell in pulmonary capillaries
Term
how regulation of breathing helps maintain homeostasis
 Definition
For metabolic homeostasis, the frequency and amplitude of breathing must respond to metabolic changes.
Term
some sensors involved in regulation of breathing
 Definition
-Chemoreceptors for chemical changes
-mechanoreceptors for mechanical changes
[image]
Term
the integrator involved in regulation of breathing
 Definition
brain
[image]
Term
the effectors involved in regulation of breathing
 Definition
respiratory muscles
[image]
Term
the respiratory centers of the brain stem
 Definition
-Rhythmicity center (medulla)
-Apneustic center (pons)
-Pneumotaxic center (pons)
[image]
Term
how the brain acts as an integrator in regulation of breathing
 Definition
-Continuous display of voluntary and involuntary actions. -Voluntary action is done by cerebrum, hypothalamus, limbic system (anger). -Involuntary action is done by the brain stem respiratory centers (medulla oblongata and pons). -Brain stem respiratory centers +Rhythmicity center (medulla) +Apneustic center (pons) +Pneumotaxic center (pons) [image][image]
Term
the 2 groups of chemoreceptors that help regulate breathing by monitoring changes in blood PCO2, PO2, and pH.
 Definition
-Central chemoreceptors
-Peripheral chemoreceptors
Term
Central chemoreceptors
 Definition
-Located in medulla, different from the rhythmicity center. -More sensitive to blood PCO2 than blood pH (due to the blood-brain barrier (BBB)).
Term
Peripheral chemoreceptors
 Definition
-Carotid and aortic bodies -Directly detect changes in PO2 -Indirectly detect changes in PCO2 through pH +H2O + CO2 <--> H2CO3 <--> H+ + HCO3- -More sensitive to changes in blood pH than PO2 [image]
Term
the types of peripheral chemoreceptors
 Definition
-Carotid bodies
-aortic bodies
Term
depiction of chemoreceptor cells and baroreceptor cells
 Definition
[image]
-Baroreceptors: Carotid sinuses and aortic arch
-Chemoreceptors: Carotid bodies and aortic bodies
Term
Pulmonary Mechanoreceptors
 Definition
-Detect mechanical changes of breathing (volume and frequency). -Influence the brain stem respiratory control centers via sensory fibers in vagus nerves. -Pulmonary stretch receptors (PSR) +detect volume changes +present in the smooth muscle of the airways +slowly adapting +activated during inspiration to force expiration
Term
Pulmonary stretch receptors (PSR)
 Definition
the main type of pulmonary mechanoreceptors
-detect volume changes
-present in the smooth muscle of the airways
-slowly adapting
-activated during inspiration to force expiration
Term
Hering-Breuer inflation reflex
 Definition
Triggered to prevent over-inflation of the lungs
[image]
Term
some types of pulmonary mechanoreceptors
 Definition
-Pulmonary stretch receptors (PSR)
-Pulmonary irritant receptors (PIR)
-Unmyelinated C fibers
Term
Pulmonary irritant receptors (PIR)
 Definition
-A.k.a. – rapidly adaptive receptors on Aδ fibers
-Detect frequency of breathing
-Respond to smoke, smog, and particulates -> cause coughing
[image]
Term
Unmyelinated C fibers
 Definition
-Sensory neurons located in lungs
-Stimulated by noxious substances such as capsaicin
-Produces initial apnea -> rapid, shallow breathing
[image]
Term
The Rhythmicity Center
 Definition
Located in medulla oblongata -generate automatic basic rhythm of breathing -Basic rhythm is irregular, erratic, and unstable. It is NOT the normal rhythm -Consists of interacting neurons that fire either during inspiration (I neurons) or expiration (E neurons) -Quiet expiration is a passive process that occurs when the I neurons are inhibited [image]
Term
I neurons
 Definition
interacting neurons in the rhythmicity center that fore during inspiration
Term
E neurons
 Definition
interacting neurons in the rhythmicity center that fore during expiration
Term
divisions of the rhythmicity center
 Definition
-dorsal respiratory group (DRG)
-ventral respiratory group (VRG)
Term
Dorsal respiratory group (DRG)
 Definition
division of the rhythmicity center that triggers inspiration
[image]
Term
Ventral respiratory group (VRG)
 Definition
division of the rhythmicity center that triggers expiration when a more forceful expiration is needed
[image]
Term
how the pons regulates breathing
 Definition
Basic rhythm generated by the medullary rhythmicity center must be adjusted by pons.
Term
the pontine centers involved in regulation of breathing
 Definition
-Apneustic center
-Pneumotaxic center
[image]
Term
Apneustic center
 Definition
Promotes long inspiration and sharp expiration (apneustic breathing).
[image]
Term
Pneumotaxic center
 Definition
-Needs to work together with apneustic center.
-Antagonizes the apneustic center’s effects.
-Inhibits inspiration, thus the normal rhythm.
[image]
Term
how the Apneustic center, Pneumotaxic center, Dorsal respiratory group (DRG), and Ventral respiratory group (VRG) interact with each other to regulate breathing
 Definition
[image]
Term
general overview of how everything interacts with each other to regulate breathing
 Definition
[image][image]
Term
some functions of the kidneys
 Definition
-regulate volume and components of ECF (plasma and interstitial fluid) through filtering of blood plasma into urine -Regulate BP through volume of blood plasma -Regulate [waste products] in blood -Regulate concentration of electrolytes (Na+, K+, H+, HCO3- & other ions) -Regulate pH of body fluids -Secrete erythropoietin +Hypoxia → ↑ erythropoietin → ↑RBC production
Term
the primary function of the kidneys
 Definition
regulate volume and components of ECF (plasma and interstitial fluid) through filtering of blood plasma into urine
Term
how kidneys are stimulated to secrete erythropoietin
 Definition
Hypoxia → ↑ erythropoietin → ↑RBC production
Term
depiction of the kidneys in the context of the urinary system
 Definition
[image]
Term
the structure of the kidney
 Definition
[image]
Term
some structural components of the kidney
 Definition
-outer cortex
-inner medulla
-Collecting ducts of nephrons (ahead)
Term
outer cortex of the kidney
 Definition
-outer component
-contains many capillaries
Term
inner medulla of the kidneys
 Definition
-inner component of the kidneys
-has 7-18 renal pyramids separated by renal columns
Term
Collecting ducts of nephron
 Definition
ahead of the kidneys, they empty into minor calyces which unite to form a major calyx
Term
path by which urine goes from kidneys to urination
 Definition
Path of urine = nephrons -> minor calyces -> major calyces -> renal pelvis -> ureters -> urinary bladder -> urethra -> exits
[image]
Term
nephron
 Definition
the functional unit of the kidney
[image]
Term
3 muscles to focus on concerning the bladder
 Definition
-Detrusor – smooth muscle – bladder wall
-Internal urethral sphincter – smooth muscle
-External urethral sphincter – skeletal muscle
[image]
Term
Micturition center
 Definition
part of the pons involved in urination
-not doing anything during the filling phase
Term
depiction of the sympathetic process of filling the bladder
 Definition
[image]
Term
some things that happen during the process of filling the bladder
 Definition
-Filling of bladder – sympathetic relaxation of detrusor and constriction of internal urethral sphincter.
-Somatic motor fibers stimulate external (lower) urethral sphincter (voluntary).
-Afferent fibers along pelvic nerve detect stretch -> stimulate sympathetic outflow from hypogastric nerve, and constant somatic firing from pudendal nerve.
[image]
Term
why the filling of the bladder is a sympathetic process
 Definition
because a nerve is actively mediating the the detrusor muscle of the bladder wall and the internal and external sphincters are being constricted
Term
the neurotransmitter(s) involved in the sympathetic process of filling the bladder
 Definition
norepinephrine for the involuntary and acetylcholine for the voluntary
Term
depiction of the parasympathetic process of emptying the bladder
 Definition
[image]
Term
some things that happen during the parasympathetic process of emptying the bladder
 Definition
-As bladder fills, afferent firing along pelvic nerve ↑↑ -> [periaqueductal grey integrates signals from spinal cord and central regions] -> triggers micturition center in pons ->…
--> Full bladder – pons signals inhibition of sympathetic and activation of parasympathetic neurons → contraction of detrusor & relaxation of internal (upper) urethral sphincter.
-Somatic motor fibers control external (lower) urethral sphincter (voluntary) – relax.
[image]
Term
the neurotransmitter(s) involved in the parasympathetic process of emptying the bladder
 Definition
acetylcholine
Term
depiction of the blood vessels in the kidneys
 Definition
[image]
Term
Renal plasma (blood) flow
 Definition
Renal plasma (blood) flow = volume of plasma (blood) delivered to kidneys over time (mL/min). *RPF is 22% of cardiac output.
Term
the path blood takes through the vessels in the kidneys
 Definition
Renal artery → interlobar artery → arcuate a. → interlobular a. → afferent arteriole → glomerulus (1st capillary) → efferent arteriole → peritubular capillaries (2nd capillary) with vasa recta surrounding loop of Henle → venous blood [image]
Term
function of the glomerulus
 Definition
filtration of blood
Term
how many nephrons are in a kidney?
 Definition
>106 units in a kidney
Term
the 2 main components of the nephron
 Definition
1. Vascular component
2. Tubular components
[image]
Term
vascular component of the nephron
 Definition
glomerulus – all of RPF passes through the glomeruli
[image]
Term
the tubular components of the nephron and the path taken
 Definition
Nephron tubule: glomerular (Bowman’s) capsule → proximal convoluted tubule (PCT) → loop of Henle (LOH) (descending limb -> thin ascending limb -> thick ascending limb) → distal convoluted tubule (DCT) → collecting duct (CD) cortical then medullary → empties into calyx
[image]
Term
types of nephrons
 Definition
1. Cortical nephron
2. Juxtamedullary nephron
[image]
Term
Cortical nephron
 Definition
originates in outer 2/3 of cortex -about 85% of nephrons are cortical nephrons *More involved in solute reabsorption and waste secretion. [image]
Term
Juxtamedullary nephron
 Definition
originates in inner 1/3 cortex *Important for producing concentrated urine. -Has longer LOH & well-developed vasa recta. [image]
Term
RPF
 Definition
Renal plasma (blood) flow
Term
GFR
 Definition
Glomerular filtration rate
Term
depiction of the structure of the glomerular structure
 Definition
[image]
[image]
Term
some components of the glomerular structure
 Definition
-Glomerulus
-Glomerular (Bowman’s) capsule
[image]
[image]
Term
Glomerulus
 Definition
tangle of capillaries within the glomerular structure
-Recall glomerulus is tuft of blood vessels
+Afferent arteriole in
+Efferent arteriole out
-Glomerular capsule + glomerulus = renal corpuscle
[image]
Term
renal corpuscle
 Definition
Glomerular capsule + glomerulus = renal corpuscle
[image]
Term
Ultrafiltrate (filtrate)
 Definition
fluid that enters glomerular space -> proximal convoluted tubule
Term
Glomerular (Bowman’s) capsule
 Definition
Surrounds glomerulus – 2 layers
-Inner layer (podocytes) lines blood vessels
-Outer layer – rounded and encompasses entire glomerulus
-Glomerular (Bowman’s) space in-between
[image]
Term
An ultrafiltrate in glomerulus must pass through, in order
 Definition
`(1) Fenestrated capillary – large pores in the endothelium.
(2) Basement membrane
(3) Slits in the processes of podocytes, which comprise the inner layer of the glomerular capsule.
-Slit diaphragms span the slits.
[image]
Term
the part of the glomerular structure the ultrafiltrate passes through
 Definition
[image]
Term
fenestrated
 Definition
having perforations, apertures, or transparent areas
Term
how fenestrated capillaries help form filtrate
 Definition
-100-400 times more permeable to plasma H2O, and solutes (electrolytes, glucose, etc.). -Small enough to prevent RBCs, platelets, WBCs, and large proteins from passing through pores.
Term
Plasma proteins are mostly excluded from the filtrate due to...
 Definition
large size and negative charge.
-The basement membranes and slit diaphragms of podocytes are lined with negative charges which repel negatively-charged proteins.
Term
why glomerular filtrate has low protein concentration
 Definition
*Filtered proteins reabsorbed by renal epithelial cells -> no proteins in urine.
[image]
Term
What are two general causes of proteinuria?
 Definition
1: proteins get through the glomerulus
2: proximal tubular cells not reabsorbing the protein
[image]
Term
glomerular filtration formed under...
 Definition
(1) hydrostatic P of blood (major, due to BP) [and colloid osmotic P of glomerular filtrate (very minor)]
[image]
Term
glomerular filtration countered by...
 Definition
(2) Hydrostatic P of glomerular filtrate
(3) Colloid osmotic P of plasma
[image]
Term
Net filtration pressure of glomerular filtration
 Definition
10 mm Hg
[image]
Term
Glomerular filtration rate (GFR)
 Definition
-Volume of filtrate produced by both kidneys each minute; this is the rate at which urine forms
-~115 mL/min in women, 125 mL/min in men -> 7.5 L/hour -> 180 L/day
-Correlates with renal function.
Term
the stages of chronic kidney disease and their associated glomerular filtration rates (GFRs)
 Definition
[image]
Term
*Volume of urine per day
 Definition
*Volume of urine is ~ 1-2 L/day (1%) --> 99% of filtrate is reabsorbed.
[image]
Term
why we pee out only 1-2 L of the 180 L produced by glomerular filtration rate (GFR)
 Definition
because volume of urine is ~ 1-2 L/day (1%) --> 99% of filtrate is reabsorbed
[image]
Term
Obligatory water loss
 Definition
minimal urine volume required to excrete metabolic waste (400 - 600 mL)
[image]
Term
Filtration (in the context of the nephron)
 Definition
from the glomerulus to form the filtrate.
[image]
Term
Reabsorption (in the context of the nephron)
 Definition
brings water and solutes out of the filtrate back into the plasma along the rest of the nephron.
[image]
Term
Secretion (in the context of the nephron)
 Definition
secreting solutes into the filtrate for excretion or elimination.
[image]
Term
Quantity of a solute excreted
 Definition
Quantity of a solute excreted = (quantity filtered + quantity secreted) - quantity reabsorbed
[image]
Term
Renal Excretion Rate
 Definition
Quantity of a solute excreted per min (mg/min)
Renal Excretion Rate = V (rate of urine formation, mL/min) x U (concentration of solute x in urine, mg/mL)
[image]
Term
Renal excretion or elimination rate
 Definition
Amount of substance removed per unit time = mg/min.
[image]
-Recall renal plasma flow (A) = mL/min.
-Recall GFR (B) = mL/min.
Term
Renal plasma clearance rate
 Definition
-Ability of kidneys to remove a specific solute (x) from plasma and excrete those molecules in the urine.
-*The volume of plasma from which a solute is completely removed by kidney per unit time = mL/min.
[image]
-Recall renal plasma flow (A) = mL/min.
-Recall GFR (B) = mL/min.
Term
how and why inulin is used to measure glomerular filtration rate (GFR)
 Definition
-If a substance is neither reabsorbed nor secreted, then the amount excreted = amount filtered
-Renal excretion of inulin – filtered but neither reabsorbed nor secreted.
-Have to administer inulin and then collect urine and blood samples.
-Its clearance rate is equal to GFR. Example, 120 mL/min.
[image]
Term
Creatinine
 Definition
a metabolite of muscle creatine formed at a constant rate
Term
how and why creatinine is used to measure glomerular filtration rate (GFR)
 Definition
-Creatinine – a metabolite of muscle creatine formed at a constant rate.
-The creatinine excretion is the function of muscle mass, less affected by diet, age, and sex.
-Measure of the plasma creatinine is a good indicator of GFR.
-Creatinine freely filters through the glomeruli and is only slightly secreted by PCT  clearance close to GFR, a little above that of inulin (~127 mL/min).
-Just measuring plasma creatinine gives a rough idea of renal function (GFR).
+(There are other non-renal reasons such as dehydration and urinary obstruction which will also affect plasma creatine.)
[image]
Term
How does determining creatinine clearance differ from determining inulin clearance?
 Definition
you make your own creatinine; you don't have to introduce creatinine
Term
What happens to plasma creatinine if glomerular filtration rate (GFR) decreases?
 Definition
increases
Term
What happens to urine creatinine if glomerular filtration rate (GFR) decreases?
 Definition
decreases
Term
depiction of the entire pathway of renal absorption
 Definition
[image]
Term
the 2 routes by which renal reabsorption can occur
 Definition
-transcellular
-paracellular
Term
transcellular route of renal reabsorption
 Definition
through tubular cells
Filtrate -> Apical membrane tubular cell -> Basal membrane tubular cell -> Interstitial fluid -> Capillary
[image]
Term
paracellular route of renal reabsorption
 Definition
between tubular cells
Filtrate -> interstitial fluid -> capillary
[image]
Term
Which fluid compartment does transcelluar route involve that paracellular does not?
 Definition
the intracellular route
[image]
Term
PCT
 Definition
proximal convoluted tubule
Term
LOH
 Definition
loop of Henle
Term
solute concentration in different parts of the PCT and LOH
 Definition
[image]
Term
some hormones that regulate salt and water transport in the distal nephron
 Definition
-Vasopressin (ADH)
-Aldosterone
Term
constituative reabsorption
 Definition
reabsorption that does not change and is not hormonally regulated
-Approximately 65% of the filtered salt & water is reabsorbed across PCT, 20% is reabsorbed across loop of Henle (LOH).
-Salt transport in the above regions (PCT & LOH) are NOT under hormonal regulation.
Term
the parts of the nephron where the kidneys can tweak the amount of salt and water that get reabsorbed
 Definition
the distal convoluted tubule (DCT) and the collecting duct (CD)
-Only 15% of the initial filtrate gets there. This 15% is reabsorbed variably, depending on level of hydration and the concentration of electrolytes in the body.
Term
the remaining 15% of initial filtrate that gets to the DCT and CD is reabsorbed variably, depending on...
 Definition
level of hydration and the concentration of electrolytes in the body.
Term
how Na+ is transported across the apical membrane in the PCT
 Definition
by facilitated diffusion (2° active transport) using Na+-glucose cotransporter, no energy spent [image]
Term
how Na+ is transported across the basolateral membrane in the PCT
 Definition
by (1°) active transport using Na+-K+ pump, energy required [image]
Term
how Na+ gets into systemic capillaries
 Definition
Diffuses across interstitial space into systemic capillaries.
[image]
Term
energy requirements of reabsorption in the PCT
 Definition
uses 6% of total energy expenditure of the body to reabsorb 65% of the filtrate
Term
what Cl- does in the reabsorption process in the PCT
 Definition
-follows Na+ (electrical attraction) –paracellular [image]
Term
what water does in the reabsorption process in the PCT
 Definition
*Water (~115 L/day) follows the osmotic pressure of salt out of PCT into interstitium then to blood (peritubular capillaries) -> no change in osmolarity. -PCT highly permeable to H2O -Aquaporin channels [image]
Term
water usually follows the Na+ ions, except in...
 Definition
the loop of Henle
Term
the mOsm right after the reabsorption in the PCT
 Definition
total [solute] remains at 300 mOsm (isotonic)
Term
Glucose and amino acids in blood are easily filtered by...
 Definition
glomeruli
Term
Normally all of the filtered glucose and amino acids are reabsorbed by...
 Definition
facilitated diffusion (2° secondary active transport) in the PCT.
-Carrier-mediated transport displays saturation.
Term
Renal transport threshold
 Definition
minimal plasma [substance] that results in excretion of that substance in the urine
Term
Renal plasma threshold for glucose
 Definition
180-200 mg/dL
Term
Glycosuria
 Definition
occurs when the transport carriers for glucose become saturated due to hyperglycemia
Term
Diabetes mellitus (DM) – When hyperglycemia results in glycosuria, a large volume of urine will be formed. Why?
 Definition
because glucose in the urine is osmotically active, holding lots of water in the filtrate that becomes urine
Term
an instrument that can be used to detect glycosuria
 Definition
urine dipstick
[image]
Term
Primarily ______ nephrons responsible for water and salt reabsorption in the loop of Henle.
 Definition
juxtamedullary
Term
depiction of the loop of Henle
 Definition
[image]
Term
Concentration gradient in renal medulla in and around the loop of Henle.
 Definition
-In order for H2O to be reabsorbed, medullary interstitial fluid must be hypertonic relative to tubular fluid. -Osmotic pressure of interstitial fluid can reach 1,200-1,400 mOsm. -Osmotic pressure of tubular fluid in descending LOH always lags a little behind until the bottom of the LOH deep in the medulla. +Starts at 300 mOsm entering LOH and reaches ~1200 mOsm at bottom. [image]
Term
the requirement for H2O to be reabsorbed in the context of the loop of Henle
 Definition
In order for H2O to be reabsorbed, medullary interstitial fluid must be hypertonic relative to tubular fluid. [image]
Term
some membranes at the thick ascending limb of the loop of Henle
 Definition
-apical membrane
-basolateral membrane
[image]
Term
what happens at the apical membrane of the loop of Henle?
 Definition
Na+ diffuses from the filtrate into the cells, accompanied by the facilitated transport of K+ and Cl- (ratio 1 Na+ : 1 K+ : 2 Cl-) [image]
Term
what happens at the basolateral membrane of the loop of Henle?
 Definition
Na+ actively transported to interstitium by Na+/K+ pump, Cl- follows Na+ passively [image]
Term
the part of the loop of Henle that's impermeable to water
 Definition
the ascending limb
[image]
Term
what happens as a result of the Na+ being removed from the ascending limb of the loop of Henle?
 Definition
As Na+ removed from ascending LOH, H2O remains -> tubular fluid (filtrate) becomes increasingly dilute (hypotonic) while the interstitial fluid in the medulla becomes relatively hypertonic. [image]
Term
Filtrate going out of ascending limb LOH to DCT is hypertonic or hypotonic?
 Definition
hypotonic
Went from 1200 at the bottom to 100 mOsm.
[image]
Term
the part of the loop of Henle that's permeable to water, but not to salts; doesn't even do active transport of salts
 Definition
the descending limb of the loop of Henle
[image]
Term
the direction the water moves in the context of the descending limb of the loop of Henle
 Definition
-surrounding hypertonic interstitial fluid draws H2O out of descending limb into capillaries. -As osmolarity of surrounding fluid ↑ -> more H2O exits -> fluid volume ↓ in tubule -> higher [Na+] and osmolarity of tubular fluid -> enters ascending limb. [image]
Term
depiction of the countercurrent multiplier system involving the loop of Henle
 Definition
[image]
Term
importance of countercurrent flow in the loop of Henle
 Definition
Countercurrent flow in opposite directions in ascending and descending limbs LOH and close proximity of loop’s limbs allow interactions.
[image]
Term
how the positive feedback (multiplier system) works in the loop of Henle
 Definition
The more salt the ascending limb extrudes -> the more concentrated the interstitial fluid -> the more water diffuses out of descending limb -> gradual increasing concentration of renal interstitial fluid, followed by LOH tubular fluid, from the cortex to inner medulla.
[image]
Term
osmolarity gradient in the interstitium around the loop of Henle
 Definition
Osmolarity ↑ as go from cortex to deep medulla
[image]
Term
the NaCl, H2O, and osmolarity in the thin descending limb
 Definition
-Amount of NaCl remains the same. -Amount of H2O ↓ -Osmolarity ↑ [image]
Term
the NaCl, H2O, and osmolarity in the thick ascending limb
 Definition
-Amount of H2O remains the same.
-Amount of NaCl ↓
-Osmolarity ↓
[image]
Term
the result of the medullary hypertonicity created by the countercurrent multiplier system
 Definition
H2O and NaCl conservation
Term
Vasa Recta
 Definition
Net of capillaries around LOH
[image]
Term
properties of the vasa recta that enable it to do countercurrent exchange
 Definition
-Walls are permeable to H2O, NaCl, & urea – passive transport. -Slow, low pressure blood flow in medulla = low hydrostatic P. -Colloid osmotic P inside vasa recta >>> surrounding interstitium. -As descend into hypertonic medulla +H2O exits the capillaries +NaCl enters the capillaries -As ascend to decreasing tonicity of cortex +H2O enters the capillaries +NaCl exits the capillaries [image]
Term
The countercurrent exchange of vasa recta
 Definition
-Hypertonic salts in interstitial fluid diffuse into blood of the descending capillary loop then passively diffuse out of the ascending capillary loop. +No net movement of salts. +*Hypertonicity of renal medullary interstitium maintained. -H2O moves out of descending limbs, but enters ascending limbs to a greater extent. +*Water returned to systemic circulation. [image]
Term
the ultimate result of the entire countercurrent mechanism
 Definition
-Ultimately, H2O and NaCl are reclaimed from filtrate. -Enough of each remains in plasma of vasa recta to maintain homeostatic levels. [image]
Term
the flow of water and NaCl in the vasa recta
 Definition
-H2O leaves descending vasa recta -H2O enters ascending vasa recta -NaCl enters descending vasa recta -NaCl leaves ascending vasa recta [image][image]
Term
the flow of water and NaCl in the loop of Henle
 Definition
-H2O leaves descending LOH -NaCl leaves ascending LOH [image][image]
Term
the role of the countercurrent multiplier in the entire countercurrent mechanism
 Definition
Countercurrent multiplier creates medullary hypertonicity.
[image]
Term
the role of the countercurrent exchange in the entire countercurrent mechanism
 Definition
Countercurrent exchange maintains medullary hypertonicity (salt remains in medulla) and conserves water in the body (water returns to circulation).
[image]
Term
where urea comes from
 Definition
Nitrogenous end product of protein metabolism -> renal elimination important
Term
structure of urea
 Definition
[image]
Term
Some urea is recycled. What is its function?
 Definition
contributes to total osmolarity of medullary interstitial fluid; helps maintain hypertonicity of interstitial fluid
Term
how urea is transported
 Definition
facilitated diffusion by urea transporters
Term
path of urea from medullary CD to ascending limb of loop of Henle
 Definition
Urea diffuses out of medullary CD -> interstitial fluid -> into ascending limb LOH
Term
DCT and cortical CD [permeable or impermeable] to urea.
 Definition
impermeable
Term
the amounts of Na+ and K+ that get reabsorbed before going into the distal convoluted tubule and make it to the distal convoluted tubule, respectively
 Definition
Approximately 85% of filtered Na+ & K+ is reabsorbed before the filtrate reaches the distal convoluted tubule (DCT), i.e. remaining 15% filtrate goes to DCT. [image]
Term
among the filtrate that makes it to the distal convoluted tubule, what happens to the Na+ in the absence of aldosterone?
 Definition
80% of the Na+ is reabsorbed in the distal convoluted tubule [image]
Term
how aldosterone regulates salt reabsorption
 Definition
it regulates remaining 20% (2-3% of the total filtrate, or ~30 g of Na+/day) of the 15% of filtrate that makes it to the distal convoluted tubule, thus affecting 2-3% of salt re-absorption.
-Aldosterone targets DCT (minor) and collecting ducts (major).
[image]
Term
Aldosterone targets...
 Definition
-DCT (minor)
-collecting ducts (major)
[image]
Term
depiction of how Na+ and K+ are handled in the renal tubules
 Definition
[image]
Term
the effect of aldosterone
 Definition
Aldosterone acts on late DCT (minor) and cortical CD (major) to reabsorb Na+ and secrete K+, thus promoting further Na+ retention and K+ loss from blood. [image]
Term
how Na+ and K+ move at the apical membrane of the DCT/CD
 Definition
they follow their diffusion gradients; this leads to saving sodium and peeing potassium
[image]
Term
how Na+ and K+ move at the basal membrane of the DCT/CD
 Definition
active transport (Na+ / K+ pump) [image]
Term
how aldosterone causes Na+ retention and K+ loss
 Definition
by going into the collecting tubule cells, binding to the intracellular receptor, and causing increased expression of the Na+ channels and the Na+ / K+ ATPases [image]
Term
the cause and effect of aldosterone secretion
 Definition
-*Stimulated directly by a rise in blood K+ and indirectly by a fall in blood Na+. -Aldosterone stimulates K+ (and H+) secretion in exchange for Na+ reabsorption. -*Aldosterone-induced Na+ reabsorption allows fine-tuning of plasma [Na+]. -*Aldosterone-induced K+ secretion is the main means by which K+ can be eliminated in the urine. +There is aldosterone-independent K+ secretion into the filtrate (minor). [image]
Term
some characteristics of the medullary CD
 Definition
-important in water reabsorption/conservation due to hypertonic interstitial fluid. -The medullary CD is permeable to water but impermeable to salts --> the high [NaCl] in the medullary interstitial fluid cannot enter the medullary CD. [image]
Term
how Antidiuretic hormone (ADH, vasopressin) stimulates H2O reabsorption
 Definition
Antidiuretic hormone (ADH, vasopressin) from the posterior pituitary stimulates incorporation of aquaporins into apical epithelial cell membranes of medullary CD --> ↑ H2O re-absorption from tubules along concentration gradient. [image]
Term
What effect does aldosterone have on blood volume?
 Definition
increases it
[image]
Term
What effect does ADH have on blood volume?
 Definition
increases it
[image]
Term
2 hormones that are involved in water conservation
 Definition
-aldosterone
-ADH
Term
What happens when excess water needs to be excreted? ADH secretion?
 Definition
we don't have release of that because we want the water to stay in the collecting ducts
[image]
Term
What happens when excess water needs to be excreted? Osmolarity of filtrate in collecting duct?
 Definition
gets fairly dilute
[image]
Term
What happens when excess water needs to be excreted? Blood volume?
 Definition
decreases
[image]
Term
What happens when water needs to be conserved? ADH secretion?
 Definition
it would occur
[image]
Term
What happens when water needs to be conserved? Osmolarity of filtrate in collecting duct?
 Definition
increases
[image]
Term
What happens when water needs to be conserved? Blood volume?
 Definition
decreases
[image]
Term
Diabetes insipidus (DI)
 Definition
a disease associated with inadequate secretion of ADH or defects in renal ADH receptors.
[image]
Term
result of Diabetes insipidus (DI)
 Definition
Medullary CD become less permeable to water --> ↓ water re-absorption into the plasma --> high volume and very dilute urine.
[image]
Term
general diagram of the pathophysiology of ADH
 Definition
[image]
Term
What are the derivations of the names of diabetes mellitus and diabetes insipidus?
 Definition
-diabetes basically means siphoning off water (it was understood that this condition caused excess urination)
-mellitus means sweet (physicians would taste the urine, sweet in this case)
-insipidus means not having a strong taste (physicians would taste the urine; nearly tasteless in this case)
Term
some ions the kidneys regulate
 Definition
-Na+ -K+ -H+ -Cl- -HCO3- -PO4-3 [image]
Term
effect of the kidneys regulating Na+
 Definition
Regulation of plasma [Na+] --> volume of blood plasma --> regulation of BP.
Term
effect of the kidneys regulating K+
 Definition
Control of plasma of [K+] for proper function of cardiac & skeletal muscles.
Term
the goal of the kidneys regulating ions
 Definition
to match ingestion with urinary excretion
Term
Role of juxtaglomerular (JG) apparatus
 Definition
Involved in renin -> -> aldosterone secretion
Term
Atrial natriuretic peptide (ANP)
 Definition
acts as an endogenous diuretic by stimulating excretion of Na+, Cl- and H2O; opposite to aldosterone. -Inhibits effects of aldosterone and ADH.
Term
What does natriuretic mean?
 Definition
sodium and urine
Term
Juxtaglomerular Apparatus
 Definition
Region in each nephron where the afferent arteriole contacts the thick ascending limb LOH (about to enter DCT) [image]
Term
types of cells in the juxtaglomerular apparatus
 Definition
-granular cells
-macula densa cells
-mesangial cells
[image]
Term
Macula densa cells
 Definition
detect [Na+] and flow -part of juxtaglomerular apparatus [image]
Term
Granular cells
 Definition
secrete renin
-part of juxtaglomerular apparatus
[image]
Term
mesangial cells
 Definition
type of smooth muscle cells in the juxtaglomerular apparatus
Term
overall function of juxtaglomerular apparatus
 Definition
Renal autoregulation
[image]
Term
Renal autoregulation
 Definition
(intrinsic mechanisms) maintains steady renal blood flow and GFR
[image]
Term
the overall local effects of macula densa cell signaling
 Definition
-When ↓ systemic arterial P --> chemicals released locally (NO, PGs) --> the afferent arterioles dilate --> maintains GFR in a constant range.
-Tubuloglomerular feedback – macula densa in ascending limb senses an increased flow of filtrate --> secretes ATP as a signal to afferent arterioles to constrict.
[image]
Term
why is renal autoregulation of renal blood flow and GFR important?
 Definition
if you had constantly widely fluctuating GFR and blood flow, that would really disrupt the cincentration gradient in the medulla and impair your ability to reabsorb sodium, reabsorb water, lose potassium, things like that
Term
Tubuloglomerular feedback
 Definition
macula densa in ascending limb senses an increased flow of filtrate --> secretes ATP as a signal to afferent arterioles to constrict. This lowers it back to the homeostatic level of filtrate being formed.
[image]
Term
Granular cells (juxtaglomerular cells)
 Definition
-Modified smooth muscle cells in the wall of afferent arterioles.
-Receive local (paracrine) signals from macula densa.
-Secrete renin causing systemic effects:
1) ↓ systemic arterial P --> --> ↑ renin secretion.
2) ↑ systemic arterial P --> --> ↓ renin secretion.
[image]
Term
how Granular cells (juxtaglomerular cells) regulate blood pressure
 Definition
The renin-angiotensin-aldosterone (RAA) system – (“negative” feedback response)
-↓ in BP → detected by granular cells → ↑ renin secretion → renin converts angiotensinogen (produced by the liver → angiotensin (AT) I
-Angiotensin-converting enzyme (ACE) converts AT I → AT II (bioactive)
-*AT II effects:
(1) → vasoconstriction → ↑ BP
(2) → ↑ aldosterone secretion (a steroid H from adrenal cortex) → ↑ in renal Na+ re-absorption → ↑ in water re-absorption → ↑ blood vol → ↑ BP
[image]
Term
the pathway showing how the renin secreted by granular cells regulates blood pressure
 Definition
[image]
Term
how sympathetic innervation helps to regulate GFR
 Definition
-Sympathetic innervation -> constriction of the afferent arterioles -> reduces GFR -> thus preserves blood volume to muscles and heart.
-Only with severe sympathetic input, e.g., shock, hemorrhage.
[image]
Term
GFR
 Definition
Glomerular filtration rate (mL/min)
Term
Summary of Local and Systemic Effects of Juxtaglomerular Apparatus and Renal Autoregulation
 Definition
[image]
Term
overview of how the renal-angiotensin-aldosterone system (RAAS) increases blood volume and pressure
 Definition
[image]
Term
depiction of how CO2, acids, buffers, and blood cells interact with each other
 Definition
[image]
Term
Blood pH is maintained within narrow pH range (7.40) by...
 Definition
lungs and kidneys
[image]
Term
normal pH of blood
 Definition
7.40
Term
Kidneys help regulate blood pH by...
 Definition
excreting H+ and/or reabsorbing HCO3- [image] -CA: catalyzed by carbonic anhydrase. -Henderson-Hasselbalch equation -pH = 6.1 + log ( [HCO3-] / [CO2] ) -[CO2] is adjusted by lungs, [HCO3-] by kidneys
Term
acidosis
 Definition
-When blood pH < 7.35 -↑ H+ ions
Term
alkalosis
 Definition
-When blood pH > 7.45 -↓ H+ ions
Term
the most important buffer in blood and what it does
 Definition
-HCO3- -Excess H+ is buffered by HCO3-
Term
the role of the proximal convoluted tubule in the handling of HCO3- and H+
 Definition
-Main site of HCO3-- reabsorption. -Na+/H+ antiporter – another source of Na+ reabsorption. -Role of carbonic anhydrase – HCO3- can not cross membranes. -H+ keeps cycling – small amounts of extra H+ secreted for excretion. [image]
Term
how bicarbonate (HCO3-) goes through the membrane of the proximal tubule
 Definition
by way of a Na+ / HCO3- cotransporter along Na+'s concentration gradient
Term
the role of the distal convoluted tubule / collecting ducts in the handling of HCO3- and H+
 Definition
-Active transport of H+ across apical membrane -> filtrate. +H+ ATPase uniporter +H+/K+ ATPase antiporter -Combines with phosphate and ammonia buffers in filtrate -> excreted. -Other mechanisms exist to ↑ HCO3- entering plasma and ↓ H+ entering filtrate. [image]
Term
depiction of the relationship between Na+, K+, and H+
 Definition
[image]
Term
Hyperkalemia
 Definition
too much K+
Term
how Na+ reabsorption in DCT and CD influences K+
 Definition
Na+ re-absorption in DCT and CD creates electrical gradient for K+ secretion (see aldosterone). [image]
Term
how plasma [K+] indirectly affects [H+]
 Definition
-↓ in ECF [K+] (hypokalemia) --> ↑ H+ secretion in distal tubule & cortical CD --> metabolic alkalosis. -Hyperkalemia --> metabolic acidosis. -Severe acidosis --> H+ is secreted at the expense of K+ --> ↑ ECF [K+] --> hyperkalemia. [image]
Term
the ions that get secreted into the filtrate and when
 Definition
Often H+ or K+ is being secreted into filtrate at the expense of the other in acute situations. [image]
Term
the ions that get moved into the plasma and cells and when
 Definition
Similar situation occurs in plasma with movement of excess H+ or K+ into cells while the other moves into plasma. [image]
Term
what hyperkalemia leads to
 Definition
acidosis
Term
why urine tends to be slightly acidic (pH 5-7)
 Definition
because kidneys reabsorb almost all HCO3- and excrete H+
Term
Nephron cannot produce urine with pH < 4.5 because...
 Definition
it has buffers
Term
H+ are prevented from contributing to the acidity of the urine by...
 Definition
being combined with HPO4-2 or NH3. -*Buffering reactions +HPO4 + H+ --> H2PO4- +NH3 + H+ --> NH4+ (ammonium ion)
Term
some buffering reactions that occur in the nephron to affect the pH of the urine
 Definition
HPO4 + H+ --> H2PO4- NH3 + H+ --> NH4+ (ammonium ion)
Term
how hypoventilation leads to respiratory acidosis
 Definition
Hypoventilation --> accumulation of CO2 in the tissues --> ↑ PCO2 --> [HCO3-] / [CO2] --> ↓ pH
Term
the compensatory response for respiratory acidosis caused by hypoventilation
 Definition
↑ renal secretion of H+ (as NH4+ and monophosphate) and ↑ re-absorption of HCO3- --> ↑ [HCO3-] / [CO2] --> ↑ pH --> blood pH close to normal
Term
how hyperventilation leads to respiratory alkalosis
 Definition
Hyperventilation --> too little CO2 --> [HCO3-] / [CO2] --> ↑ pH
Term
the compensatory response for respiratory alkalosis caused by hyperventilation
 Definition
↓ re-absorption of HCO3- --> ↓ [HCO3-] / [CO2] --> ↓ pH ↓ blood pH close to normal
Term
the equation that regulation of blood pH boils down to
 Definition
CO2 + H2O <--> H2CO3 <--> H+ + HCO3-
Term
Metabolic acidosis
 Definition
excess of nonvolatile acids
Term
some things that can cause metabolic acidosis
 Definition
-↑ acid intake or production -↓ renal excretion of H+ -Ketoacidosis in diabetes -lactic acidosis -loss of HCO3- (for buffering) in diarrhea -renal tubular disorders or renal failure -toxicants
Term
the pathway that leads to metabolic acidosis
 Definition
↑ acid intake, production, or ↓ renal excretion of H+ --> ↓ ratio of [HCO3-] / [CO2] --> ↓ pH --> metabolic acidosis
Term
Compensatory response for metabolic acidosis
 Definition
hyperventilation by lungs --> ↓ CO2 --> ↑ ratio of [HCO3-] / [CO2]
Term
Metabolic alkalosis
 Definition
too much HCO3- or too little nonvolatile acids (e.g. from vomiting stomach acid)
Term
the cause and effect leading to metabolic acidosis
 Definition
↑ HCO3- or acid loss --> ↑ ratio of [HCO3-] / [CO2] --> ↑ pH --> metabolic alkalosis
Term
compensatory response for metabolic alkalosis
 Definition
hypoventilation by lungs --> ↑ CO2 --> ↓ ratio of [HCO3-] / [CO2]
Term
depiction of the pulmonary and renal responses to acidosis
 Definition
[image]
Term
depiction of the pulmonary and renal responses to alkalosis
 Definition
[image]
Term
why we need body defense (immune system)
 Definition
Defense mechanism
-Protect against disease-causing agents (pathogens)
-Make up the immune system
Term
pathogens
 Definition
disease-causing agents
Term
Innate defense
 Definition
inherited; nonspecific
-Serves as a first line of defense
Term
Adaptive defense
 Definition
specific
-A function of lymphocytes & changes with exposure
Term
some types of external defenses in innate defense
 Definition
-skin
-saliva
-tears
-mucus
-"good" gut bacteris to outcompete the bad
-stomach acid
-epithelial barriers
Term
some epithelial barriers that function in innate defense
 Definition
-Digestive tract (gastric acid, enzymes)
-Respiratory tract (mucus, cilia, enzymes)
-Genitourinary tract (acidity, pH ~4)
Term
some types of internal defense mechanisms
 Definition
-fever
-interferons
-phagocytes
Term
why the integrity of the skin is important for defense
 Definition
because if there's a cut, bacteria can infect and inflammation can result
Term
how stomach acid functions in external defense
 Definition
degrading bacteria
Term
how mucus, cilia, and enzymes in the respiratory tract function in external defense
 Definition
-mucus entraps unwanted particle
-cilia move it upward
-enzymes digest it
Term
how the acidity of the genitourinary tract (pH ~4)
 Definition
reduces growth of bacteria
Term
antigen (Ag)
 Definition
molecules that elicit adaptive immunity specifically bind to Ag; they mediate specific immunity
-Usually large molecules that are foreign to the body
-this is how the immune system distinguishes self from non-self
Term
Specific immunity
 Definition
mediated by antigens (Ag)
Term
types of specific immunity
 Definition
-Humoral immunity
-Cell-mediated immunity
Term
Humoral immunity
 Definition
uses antibodies (Ab) produced by B cells
[image]
Term
Cell-mediated immunity
 Definition
uses T cells to destroy host cells infected by pathogens
[image]
Term
innate immunity triggered by...
 Definition
pathogen-associated molecular patterns (PAMPs)
Term
the difference between Gram-negative and Gram-positive bacteria
 Definition
whether or not there's an envelope outside the cell wall
Term
immune cells recognize PAMPs by...
 Definition
Toll-like receptors (TLR’)
Term
the surface molecule on Gram-negative bacteria
 Definition
Lipopolysaccharide (LPS) from Gram “–” bacteria cell membrane
Term
the surface molecule on Gram-positive bacteria
 Definition
Peptidoglycan from Gram “+” bacteria cell wall
Term
the result of PAMPs binding to TLR' to form the PAMPs-TLR’ complex
 Definition
PAMPs-TLR’ complex → ↑ cytokines secretion from immune cells → activate more immune cells for further body defense → inflammation most likely to occur
Term
cytokine
 Definition
it's to stimulate cells to work on something. We call that cytokine. The cytokines secreted by immune cells will activate other immune cells to be more active for a general body defense, and include an induction of inflammation
Term
difference between Gram-positive and Gram-negative based on Gram-staining
 Definition
Gram staining
-Detect the presence of peptidoglycan (Gram “+”) on cell wall of bacteria
-Gram “+” bac – stained as purple/blue due to retaining crystal violet dye
-Gram “–” bac – stained as pink/red due to the existence of an outer membrane
+More resistant against antibodies, because of their impenetrable wall
Term
Inflammation
 Definition
a part of the healing process when tissues are injured by pathogens, trauma etc.
-Inflammation initiates nonspecific phagocytosis by blood phagocytes (WBCs)
-Characteristics of inflammation
+Redness, swelling and pus, warmth, pain
Term
inflammation is initially caused by...
 Definition
induction by PAMPs binding to TL receptor, and then initiate the inflammation
Term
what causes the redness, swelling, and warmth in inflammation?
 Definition
vasodilation
Term
Inflammation initiates...
 Definition
nonspecific phagocytosis by blood phagocytes (WBCs)
Term
Characteristics of inflammation
 Definition
-Redness
-swelling
-pus (not always; depending on the nature of the bacterial infection)
-warmth
-pain
Term
how inflammation is initiated
 Definition
Injured (infected) tissues release cytokines
→ Activate mast cells near the damaged area
→ Mast cells secrete cytokines (histamine, TNF-α, prostaglandins & leukotrienes) → dilation of blood vessels → ↑ membrane permeability → allows white blood cells to leave the blood vessel
[image]
Term
TNF-α
 Definition
tumor necrosis factor alpha
Term
Effects of Cytokines from Mast Cells
 Definition
-Vasodilation
-Chemotaxis
Term
vasodilation in the inflammatory pathway leads to...
 Definition
diapedesis (extravasation)
[image][image]
Term
diapedesis (extravasation)
 Definition
blood phagocytes exit capillaries by pseudopod movement attracts WBCs
-a kind of activity that WBC inside the blood vessel going out to the infected area
[image][image]
Term
Chemotaxis
 Definition
recruit blood monocytes to the injured tissues or infected cell → macrophages → phagocytosis
[image][image]
Term
Cytokines lead to...
 Definition
constriction of bronchi & bronchioles for protection of further entry of pathogen into respiratory tract
-If too severe → asthma
Term
meaning of the word vasation
 Definition
part of the blood vessel
Term
meaning of the word extravasation
 Definition
go out of the blood vessel
Term
the only time RBC goes out of the blood vessel
 Definition
when there's a hematoma, in which the inflammatory area or the swelling area is accompanied by the presence of RBC
Term
why WBC can exit the blood vessel while RBC can't, even though WBC is about twice as big as RBC
 Definition
because WBC can do psudopod movement while RBC can't
[image][image]
Term
why the WBC can do pseudopod movement while the RBC can't
 Definition
chemotaxis (a type of biochemical signaling)
Term
phagocytosis in the inflammation process
 Definition
Degradation of bacteria or injured cells by macrophages
[image]
Term
the pathway by which phagocytosis occurs in the inflammation process
 Definition
-Tissue damage --> cell necrosis --> expressed danger-associated molecular patterns (DAMPs) --> ↑ innate immunity & inflammation
-Pseudopod movement by macrophages --> vacuole formation --> fuse with lysosomes --> phagolysosomes
[image]
Term
DAMPs
 Definition
danger associated molecule patterns
-expressed by the damaged tissue of our own cells
-can initiate in innate immunity and inflammation
[image]
Term
depiction of how phagocytosis occurs in the infected area
 Definition
[image]
Term
Cells die by apoptosis (do or do not) express DAMPs
 Definition
do not
Term
the types of phagocytes that arrive to the infected area and the order in which they arrive
 Definition
1: neutrophils (pus formation)
2: blood monocytes (become macrophages and may serve as antigen presenting cells)
3: T lymphocytes, for specific immunity
[image][image]
Term
neutrophils
 Definition
-first phagocyte to arrive to the infected area
-fights against pathogen, resulting in pus formation
Term
pus
 Definition
the dead body of the neutrophil together with a dead body of the bacteria
Term
monocyte
 Definition
-second phagocyte to arrive to the infected area
-in response to chemotaxis, monocytes send information from the damaged area
-engulfs bacteria
-present antigen from pathogen to other WBCs, including lymphocytes, to perform body defense
Term
T lymphocytes
 Definition
-3rd phagocyte to arrive
-last resort
-responds to antigen presented by monocyte to produce specific immunity
Term
Body temperature is regulated by...
 Definition
hypothalamus (thermostat)
Term
fever can be induced by...
 Definition
-Exogenous pyrogens (LPS)
-Endogenous pyrogens such as interleukins (IL), or
-Endotoxin from gram “–” bac (LPS)
Term
how Endotoxin from gram “–” bac (LPS) causes fever
 Definition
Endotoxin from gram “–” bac (LPS) --> stimulates WBCs --> release endogenous pyrogens (IL1-β & other cytokines) --> alter set point in hypothalamus of the brain
Term
Effects of fever
 Definition
-Nonspecifically ↓ bac
-↑ neutrophil activities
-↑ interferon production
Term
Pyrogens
 Definition
substance that can induce fever
Term
Interleukins
 Definition
-chemicals released by WBC, leukocyte, for the communication between leukocyte. We call that interleukin
-interleukins rely on these chemicals between WBC and then induce fever.
Term
Interferons
 Definition
-Are polypeptides produced by cells infected with virus
-Provide short-acting, non-specific resistance to viral infection in nearby cells
-they alert nearby cells to be more active against virus
Term
types of interferons
 Definition
-α interferons
-β interferons
-γ interferons
Term
Effects of interferons
 Definition
-↑ Overall immune activities by ↑ phagocytosis, ↑ killer T cell activities, ↑ natural killer cell activities, ↑ Ab production by plasma cells
-↓ tumor growth, ↓ cell division, ↓ maturation of adipocytes, RBC
Term
adaptive immunity relies on...
 Definition
lymphocytes
Term
types of lymphocytes
 Definition
-B cells (B lymphocytes)
-T cells (T lymphocytes)
Term
origin of B cells (B lymphocytes)
 Definition
evidently bursa of Fabricius
-Named after lymphocytes processed from chicken bursa of Fabricius
Term
origin of T cells (T lymphocytes)
 Definition
thymus
Term
types of B cells (B lymphocytes)
 Definition
-Memory cells
-plasma cells
Term
Thymus
 Definition
a kind of lymphoid tissue that present during gestation in fetus, or early childhood
Term
what happens to the thymus as the person gets older?
 Definition
-gets replaced more and more by fat tissue, or adipose tissue
-when this happens, the T cells go into circulation
Term
most lymphocyte cells in the blood are...
 Definition
T cells (T lymphocytes) (65-85% of blood lymphocytes)
Term
where most B cells (B lymphocytes) are found
 Definition
lymphoid tissue, such as spleen, such as local lymph nodes
Term
types of T cells (T lymphocytes)
 Definition
-Killer (cytotoxic) T Cells
-helper T cells
-suppressor T cells
Term
HIV virus specifically attacks...
 Definition
helper T cells
Term
the "humoral" in humoral immunity means...
 Definition
fluid
Term
B-cell (humoral) immunity based on...
 Definition
production of antibodies, which are soluble in fluid
Term
why B-cell-mediated immunity is called humoral immunity
 Definition
because the word humoral means "fluid," and it's based on production of antibodies, which are soluble in fluid
Term
B cells expand into clones, which are...
 Definition
-memory cells
-plasma cells
[image]
Term
Memory cells
 Definition
-long lifespan
-have the memory of this structure of a specific antigen for a long time
-waiting for the second infection by that antigen, and to expand the clone
Term
Plasma cells
 Definition
-factory (2K Ab/sec)
-short-lived
Term
Combined work of memory cells and plasma cells
 Definition
Combined work of memory cells and plasma cells --> Ab production
Term
antibodies (Ab)
 Definition
type of globulin protein with immune function (immunoglobulin (Ig))
Term
structure of antibodies (Ab)
 Definition
shape of “Y” -2 long heavy (H) chains + 2 light (L) chains -Each chain contains constant (Fc) and variable fragments (Fab) [image]
Term
variable (Fab) fragment of antibody
 Definition
confers antibody (Ab) specificity
[image]
Term
the diversity of antibodies we have
 Definition
1020 different Ab/person
Term
why are so many antibodies possible if we have a limited number of genes?
 Definition
because we use recombination of different genetic segment, and to produce antibody that adapt to different kind of antigen and specificity
-Recombination of genes code for Hs and Ls in developing lymphocytes --> Ag-independent diversity
-Diversity further increases via somatic hypermutation --> B cells undergo Ag-dependent proliferation
Term
some categories of antibodies
 Definition
-IgG
-IgA
-IgE
-IgM
-IgD
Term
most common type of antibodies
 Definition
IgG antibodies
Term
IgG antibodies
 Definition
main Ab in circulation
Term
IgA antibodies
 Definition
main Ab in external secretions in mucosal area, such as respiratory mucosa, digestive mucosa, reproductive mucosa
-they are secreted from the mucosa into the lumen of the tract, becoming secretory IgG
Term
IgE antibodies
 Definition
responsible for allergic symptoms
Term
IgM and IgD antibodies
 Definition
as Ag R (I think antigen receptors) on lymphocytes
Term
secretory IgG
 Definition
IgA antibodies that are secreted from the mucosal area into the lumen
Term
Killer (cytotoxic) T cells
 Definition
have CD8 surface marker
-Kill pathogens by cell-mediated destruction – in contact with victim cell
-Secrete perforins --> create a pore in victim's membrane --> lysis
-Secrete granzymes --> destroy victim's DNA
[image]
Term
Helper T cells
 Definition
have CD4 surface marker
-↑ Responses of both killer T cells and B cells
-HIV infects helper T cells and macrophages
[image]
Term
Suppressor (regulatory) T cells
 Definition
have CD25 & CD4 surface markers
-↓ Responses of killer Ts and B cells; help protect against autoimmune responses
[image]
Term
Lymphokines
 Definition
secreted by lymphocytes
-Usually called interleukin (IL)- 1, 2, 3
-they help mediate the activity of the T-cell
Term
depiction of stem cells turning into B and T lymphocytes and what they do
 Definition
[image]
Term
why immunity mediated by T cells is called cell-mediated immunity
 Definition
because those T cells make contact with the pathogen
Term
how Killer (cytotoxic) T cells kill pathogens
 Definition
-Secrete perforins --> create a pore in victim's membrane --> lysis
-Secrete granzymes --> destroy victim's DNA
Term
granzymes
 Definition
enzymes for destroying the pathogen's DNA
Term
perforins
 Definition
create pores in pathogen's membrane
Term
Suppressor (regulatory) T cells help protect against...
 Definition
autoimmune responses
Term
Active immunity
 Definition
Require prior exposure to the specific Ag (vaccines)
-Eg. Jenner’s cowpox inoculation against smallpox
Term
Vaccines may use...
 Definition
(1) live attenuated virus
(2) killed virus
(3) recombinant viral proteins
Term
Passive immunity
 Definition
Donor was given active immunity, Ab --> recipients
-the recipient of the antibodies and the antivenom doesn't have time to develop active immunity
Term
comparison of active and passive immunity
 Definition
[image]
Term
why being exposed to the antibodies a second time may cause an allergic response
 Definition
because it already induced an antigenic effect that the active immunity will react to
Term
GI tract aka...
 Definition
gut, alimentary canal
Term
some components of the digestive tract
 Definition
-oral cavity
–pharynx
-upper pharyngoesophageal sphincter
-esophagus
-lower gastroesophageal sphincter
-stomach
-pyloric sphincter
-small intestine
-ileocecal valve
-large intestine (cecum, colon, rectum)
-anus
-internal anal sphincter
-external anal sphincter
[image]
Term
divisions of the small intestine
 Definition
-duodenum
-jejunum
-ileum
Term
lenth of the GI tract in adults
 Definition
30 feet
Term
some accessory organs for the digestive system
 Definition
-teeth
-tongue
-salivary glands
-liver
-gall bladder
-pancreas
Term
the 4 general layers of the GI tract
 Definition
-mucosa
-submucosa
-muscularis
-serosa
[image][image]
Term
mucosa (mucosal layer)
 Definition
-the layer closest to the lumen, where the food is
-lined with epithelial cells
-lamina propria below the epithelium
-muscularis mucosa below the lamina propria
[image][image]
Term
muscularis mucosa
 Definition
muscular tissue that helps with folding of the gut in the small intestine and the stomach
[image][image]
Term
submucosa
 Definition
-layer of connective tissue below the mucosa
-blood vessels and main lymphatics run thru it
-contains the submucosal plexus
[image][image]
Term
submucosal plexus
 Definition
within the submucosa
[image][image]
Term
myenteric plexus
 Definition
-in the muscularis layer
-between 2 muscular layers
-communicates with neurons
[image][image]
Term
the smooth muscle layers of the muscularis
 Definition
-inner circular layer
-outer longitudinal layer

they're governed by the autonomic and enteric nervous systems
[image][image]
Term
serosa
 Definition
An outer epithelial membrane that covers the surface of a visceral organ
-thinner outside layer
-adjacent to it is the abdominal cavity
[image][image]
Term
mesentary
 Definition
tissue that kinda lines the gut and is where the vessels, lymphatics, and most of the nerves run into the gut
Term
the most diverse layer of the GI tract
 Definition
mucosa, especially the epithelial layer
Term
villi
 Definition
protrusions of the mucosa into the lumen
Term
crypts
 Definition
inpouchings down into the laminar propria
-their main job is to absorb nutrients
Term
protective mucosa
 Definition
-characterized by squamous epithelium
-found in the oral cavity, pharynx, esophagus, and anal canal
Term
secretory mucosa
 Definition
-contains cells that are responsible for the secretion of digestive enzymes
-found only in the stomach
Term
absorptive mucosa
 Definition
-contains crypts and villi
-responsible primarily for absorbing digested nutrients
-found along the entirety of the small intestine
Term
absorptive and protective mucosa
 Definition
-specializes in water absorption and mucous secretion
-found in the large intestine
Term
some general digestive activities in the GI tract
 Definition
-Motility
-Secretion
-Digestion
-Absorption
-Storage
-Elimination
-Regulation
[image]
Term
how the GI tract does Motility
 Definition
-mastication (chewing)
-deglutition (swallowing)
-peristalsis
-segmentation
-haustration
-defecation
Term
how the GI tract does Secretion
 Definition
-endocrine (hormones)
-paracrine
-exocrine (enzymes, electrolytes, HCl & water)
Term
how the GI tract does Digestion
 Definition
breaking down food
Term
how the GI tract does Absorption
 Definition
digested food enters blood or lymph
Term
how the GI tract does Storage
 Definition
stomach and colon
Term
how the GI tract does Elimination
 Definition
bile and indigestible food
-some substances are put into the bile to be eliminated
Term
how the GI tract does Regulation
 Definition
neural (enteric nervous system ENS and ANS) and hormonal
Term
peristalsis
 Definition
Waves of smooth muscle contraction in smooth muscles of the tubular digestive tract. It involves circular and longitudinal muscle fibers at successive locations along the tract and serves to propel the contents of the tract in one direction.
Term
segmentation
 Definition
segments of the gut constricting on food
Term
deglutation
 Definition
swallowing
Term
haustration
 Definition
kinda like peristalsis and segmentation in the colon
Term
endocrine functions in the GI tract
 Definition
hormones
Term
paracrine and exocrine functions in the GI tract
 Definition
enzymes, electrolytes, HCl & water
Term
Digestion
 Definition
breaks down non-absorbable polymers (carbohydrates, fats, and proteins) into absorbable monomer (mostly) building blocks
-obtains basic organic molecules to make ATP, build tissues, and serve as cofactors and coenzymes.
[image]
Term
how digestion degrades non-absorbable molecules into smaller, absorbable molecules
 Definition
Hydrolysis into monomers, aided by specific enzymes
[image]
Term
what the basic molecules obtained by digestion are used for
 Definition
to make ATP, build tissues, and serve as cofactors and coenzymes
Term
function of the oral cavity
 Definition
-chewing
-Mixes food with saliva which contains salivary amylase, mucus, growth factors.
-1st stage of deglutition (oral stage, which is voluntary)
[image]
Term
the function of the pharynx
 Definition
-2nd stage of deglutition (Pharyngeal stage, which is involuntary)
Term
function of the esophagus
 Definition
-Deglutition (swallowing)
-3rd stage of Deglutition (esophageal stage, which is involuntary)
Term
the stages of Deglutition (swallowing)
 Definition
1: Oral stage (voluntary) – bolus moved to pharynx
2: Pharyngeal stage (involuntary) – soft palate covers nasopharynx, vocal folds close and epiglottis covers them (larynx), upper esophageal sphincter relaxes.
3: Esophageal stage (involuntary) – peristalsis moves food down esophagus to stomach.
[image]
Term
the salivary glands in the oral cavity
 Definition
-parotid
-submandibular
-sublingual
[image]
Term
what the soft pallate does during swallowing
 Definition
covers the nasopharynx to keep food and liquid from going into your nasal passages
-the vocal folds close to cover the epiglottis
[image][image]
Term
Oral stage of swallowing
 Definition
-voluntary
–bolus moved to pharynx
[image]
Term
Pharyngeal stage of swallowing
 Definition
involuntary – soft palate covers nasopharynx, vocal folds close and epiglottis covers them (larynx), upper esophageal sphincter relaxes

Bolus is moved out of pharynx --> through upper esophageal sphincter --> into esophagus.
[image]
Term
Esophageal stage of swallowing
 Definition
-involuntary
–peristalsis moves food down esophagus to stomach
[image][image]
Term
the movement of bolus through esophagus before it gets to the lower esophageal sphincter
 Definition
-*Upper third contains skeletal muscle, transitions to smooth m.
-Passes through diaphragm via hiatus.
[image]
Term
the movement of bolus through esophagus when it gets to the lower esophageal sphincter
 Definition
Lower esophageal sphincter
-Relaxes to allow bolus to pass.
-Closed to prevent regurgitation; heart burn – gastroesophageal reflux disease (GERD)
[image]
Term
heart burn (gastroesophageal reflux disease (GERD))
 Definition
when stomach acid goes into the esophagus due to the failure of the lower esophageal sphincter to close properly
-it causes erosions
[image]
Term
Esophageal Peristalsis
 Definition
Series of localized reflexes in response to distention of wall by bolus.
-uses a peristaltic wave
[image]
Term
Peristaltic wave
 Definition
coordinated, wave-like muscular contractions
[image]
Term
how the peristaltic wave occurs in the esophagus
 Definition
-Circular smooth muscle contracts on the proximal side and relaxes on the distal side of the bolus --> followed by longitudinal contraction (shortening) of smooth muscle. -After food passes into stomach, lower esophageal sphincter constricts. -*These principles apply throughout the GI tract. -this is a lot faster in the esophagus than in the small intestine [image]
Term
proximal
 Definition
closer to the mouth
Term
distal
 Definition
closer to the anus
Term
distention
 Definition
The state of being distended, enlarged, swollen from internal pressure
Term
depiction of how deglutition (swallowing) is neurologically controlled
 Definition
[image][image]
Term
the parts of the stomach
 Definition
-Cardia
-fundus
-body
-antrum
-pylorus
-pyloric sphincter
-Gastric glands (deeper in the mucosa)
[image]
[image]
Term
Functions of the stomach
 Definition
-Stores food
-Churns food to mix with gastric secretions
-Initiates digestion of proteins via secretions
-Kills bacteria
-Moves food (chyme) into the small intestine
Term
cardia
 Definition
where the food enters the stomach
[image]
[image]
Term
rugae
 Definition
-in the stomach
-allow the stomach to expand
[image]
[image]
Term
chyme (pronounced "kyme")
 Definition
digested food in the stomach and intestines
-stops being chyme when it gets turned into feces
Term
the 3 muscle layers in the stomach
 Definition
1: inner Oblique
2: Circular
3: outer Longitudinal
[image]
Term
what the stomach does in terms of motility
 Definition
-mixing
-emptying
Term
how the stomach does mixing during motility
 Definition
weak peristaltic constricting waves fundus to antrum
-Food + gastric secretions --> chyme
-Pyloric sphincter “closed”
[image]
Term
how the stomach does emptying during motility
 Definition
strong peristaltic waves starting in antrum to pylorus
-Pyloric sphincter “relaxed” --> chyme enters duodenum.
-Full duodenum --> pressure closes pyloric sphincter
[image]
Term
where gastric glands are found
 Definition
gastric pits; the mucosa contains numerous gastric pits
Term
Gastric glands
 Definition
line the pits and secrete exocrine molecules and water (gastric juice) into lumen, and endocrine and paracrine signaling molecules into interstitial space of mucosa.
[image]
Term
some types of cells within the gastric glands
 Definition
(1) Goblet cells (mucous neck cells)
(2) Parietal cells
(3) Chief cells
(4) Enterochromaffin-like cells (ECL)
(5) G cells
(6) D cells
(7) Ghrelin cells
[image]
Term
Goblet cells (mucous neck cells)
 Definition
cells inside the gastric glands that secrete mucus & bicarbonate as protection against stomach acid
[image]
Term
Parietal cells
 Definition
cells inside the gastric glands that secrete gastric acid (HCl), which breaks down food, and intrinsic factor (IF), which helps absorb vitamin B12, which is used for making heme [image]
Term
Chief cells
 Definition
cells inside the gastric glands that secrete pepsinogen, which is important for protein digestion
[image]
Term
Enterochromaffin-like cells (ECL)
 Definition
cells inside the gastric glands that secrete the paracrine molecules histamine and serotonin to trigger function of neighboring cells
[image]
Term
G cells
 Definition
cells inside the gastric glands that secrete gastrin endocrine hormone
[image]
Term
D cells
 Definition
cells inside the gastric glands that secrete somatostatin – paracrine and endocrine – inhibits secretion of multiple GI hormones
[image]
Term
Ghrelin cells
 Definition
cells inside the gastric glands that secrete ghrelin – ↑ during fasting --> stimulate hunger
[image]
Term
intrinsic factor (IF)
 Definition
the only essential function in stomach – polypeptide that promotes absorption of vitamin B12 in the ileum --> helps prevent pernicious anemia
Term
the reaction that produces H+ in the cytosol of the goblet cells in the stomach
 Definition
CO2 + H2O --> H+ + HCO3- by carbonic anhydrase [image]
Term
transport of ions at the apical membrane in the process of making gastric acid (HCl)
 Definition
H+ is secreted into gastric lumen by primary active transport, through H+/ K+ ATPase (proton pump), Cl- is secreted through facilitated diffusion. [image]
Term
concentration of H+ in lumen vs. that in parietal cells
 Definition
3 x 106 times more H+ in lumen than inside parietal cells [image]
Term
transport of ions at the basolateral membrane in the process of making gastric acid (HCl)
 Definition
HCO3- exits cells against its electrochemical gradient, by coupling its transport with Cl- following gradient – secondary active transport [image]
Term
how gastric acid (HCl) secretion is regulated neurologically
 Definition
enteric and parasympathetic nervous systems (ACh) stimulates parietal & ECL cells.
-Binds muscarinic Rs.
[image]
Term
how gastric acid (HCl) secretion is regulated by endocrine means
 Definition
gastrin from G cells, carried to parietal & ECL cells by blood circulation
[image]
Term
how gastric acid (HCl) secretion is regulated by paracrine means
 Definition
ECL cells secrete histamine --> binds H2 Rs on parietal cells [image]
Term
Enterochromaffin-like (ECL) cells
 Definition
Enterochromaffin-like cells -secrete histamine --> binds H2 Rs on parietal cells [image]
Term
the role of acetylcholine in the regulation of gastric acid (HCl) secretion
 Definition
-binds muscarinic receptors -ultimately triggers intracellular signaling, leading to activity of the H+ / K+ ATPase pump [image]
Term
the 3 phases of regulation of stomach activities
 Definition
-Cephalic phase
-Gastric phase
-Intestinal phase
Term
Cephalic phase of regulation of stomach activities
 Definition
sight, smell, & taste of food --> ↑ vagal tone, gastrin and histamine activation --> ↑ secretion.
-increases tone to the vagus nerve
-"anticipating food"
Term
Gastric phase of regulation of stomach activities
 Definition
food in stomach --> physical distension and chemical nature of chyme (amino acids etc. ) --> ↑ secretion.
-Positive feedback– ↑ secretion of HCl and pepsinogen --> ↑ gastric secretion.
Term
Intestinal phase of regulation of stomach activities
 Definition
gastric activity inhibited when chyme enters the small intestine.
Term
function of stomach
 Definition
digestion and small amount of absorption
Term
function of HCl in the stomach
 Definition
HCl functions to provide an acidic gastric environment
-Denatures ingested proteins
-Activates pepsinogen to pepsin (pH = 2).
-Kills bacteria
Term
how digestion occurs in the stomach
 Definition
-Proteins denatured and partially digested by pepsin  more digestible.
-Carbohydrate digestion by salivary amylase is soon inactivated by acidity.
Term
why carbohydrate digestion by salivary amylase stops in the stomach
 Definition
because it gets inactivated by acidity
Term
some molecules that can get absorbed through the stomach lining
 Definition
-Alcohol (ethanol) – main absorption site is the small intestine.
-Aspirin and salicylates – unionized at gastric pH.
Term
why aspirin and salicylates can get absorbed through the stomach lining
 Definition
because they're unionized at gastric pH
Term
how alkaline mucus functions as a chemical protective mechanism in the stomach
 Definition
it contains HCO3- and forms a barrier against actions of pepsin & acid. [image]
Term
some physical protective mechanisms in the stomach
 Definition
-Tight junctions
-Rapid rate of cell division
[image]
Term
how tight junctions function as a physical protective mechanism in the stomach
 Definition
between adjacent cells; keeps acid from getting between cells
[image]
Term
how rapid rate of cell division functions as a physical protective mechanism in the stomach
 Definition
entire epithelium replaced in 3 days
-they wear out fast
-the new cells work their way up from the gastric pits
[image]
Term
where the new cells for the stomach epithelium come from
 Definition
the gastric pits
Term
how prostaglandins help to protect the stomach epithelium
 Definition
*Prostaglandins E2 (PGE2) and I2 (PGI2) --> ↓ gastric acid & ↑ mucus secretions, ↑ mucosal blood flow. -they're "housekeeping" prostaglandins [image]
Term
how Prostaglandins E2 and I2
 Definition
-helps decrease gastric acid and increase mucus secretions
-nutritive
-helps remove metabolic waste products
Term
Peptic Ulcers
 Definition
Erosions of mucosa of stomach or duodenum
[image]
Term
chemicals that can damage lining to produce an ulcer
 Definition
-HCl
-pepsin
Term
some causes of peptic ulcers
 Definition
-gastrin-secreting tumor -Helicobacter pylori -NSAIDs (aspirin, ibuprofen, etc.)
Term
how NSAIDs (aspirin, ibuprofen, etc.) cause peptic ulcers
 Definition
by inhibiting paracrine secretion of PGE2 & PGI2
Term
some treatments for ulcers
 Definition
-Proton pump inhibitors such as omeprazole (Prilosec) -Histamine receptor (H2) blockers such as famotidine (Pepcid) and ranitidine (Zantac) -Antibiotics
Term
the 3 sections of the small intestine
 Definition
-Duodenum
-Jejunum
-Ileum
[image]
Term
Duodenum
 Definition
–short
-Bile and pancreatic duct empty here
[image][image]
Term
Jejunum
 Definition
2/5 length of small intestine
[image]
Term
Ileum
 Definition
3/5 length of small intestine
-Ileocecal valve into colon
[image][image]
Term
Ileocecal valve
 Definition
the valve through which the chyme goes from the ileum into the colon
[image]
Term
some structural components of the small intestine
 Definition
-Folds (plicae circulares)
-villi
-microvilli (aka the brush border)
-Epithelial cells (enterocytes)
-goblet cells
-intestinal crypts
-Lamina propria
+lymphocytes
+capillaries
+central lacteal
[image]
Term
the structures in the small intestine that increase surface area to let it do its job more efficiently
 Definition
Folds (plicae circulares) --> villi --> microvilli (also known as the brush border) [image]
Term
Epithelial cells (enterocytes) interspersed with...
 Definition
goblet cells
Term
enterocytes
 Definition
epithelial cells of the small intestine
Term
how the epithelial cells at the tips of villi are maintained
 Definition
-exfoliated
-replaced by mitosis in intestinal crypts
Term
where the new enterocytes (epithelial cells of the small intestine) come from
 Definition
intestinal crypts
Term
Lamina propria contains...
 Definition
-lymphocytes
-capillaries
-central lacteal
Term
functions of the small intestine
 Definition
complete digestion and absorption of carbohydrates, proteins, and fats
Term
enzymes needed for digestion in the small intestine
 Definition
-pancreatic enzymes
-brush border enzymes
Term
why absorption in the small intestine is very rapid
 Definition
villi and microvilli
Term
Brush border enzymes
 Definition
attached to surface of microvilli – not secreted
Term
advantage of the brush-border enzymes being attached to the surface of the microvilli instead of floating around
 Definition
makes them last longer due to negating the need to continue synthesizing them
[image]
Term
what the duodenum and jejunum absorb
 Definition
-carbohydrates -amino acids -lipids -iron -Ca2+ -H2O
Term
what the ileum absorbs
 Definition
-bile salts -vitamin B12 -electrolytes -H2O
Term
some ways water gets into the GI tract
 Definition
-Diet
-saliva
-gastric secretions
-bile
-pancreatic juice
-SI secretions
-colonic secretions
[image]
Term
some ways water gets out of the GI tract
 Definition
-SI reabsorption
-colonic reabsorption
[image]
Term
water that enters the GI tract, but does not get reabsorbed, is lost in...
 Definition
feces
[image]
Term
where water gets absorbed in the GI tract
 Definition
-mostly small intestine (all but ~2L)
Term
how water absorption occurs in the small intestine
 Definition
absorbs all but ~ 2 L of ingested H2O, and H2O from GI secretions -Absorbs Na+ and Cl- via facilitated diffusion. -Na+ cotransported with glucose. -Na+, K+ ATPase pump moves Na+ out of enterocytes into interstitial fluid. -Water follows Na+ by osmosis. [image]
Term
how water absorption occurs in the large intestine
 Definition
-absorbs Na+ via facilitated diffusion -H2O follows by osmosis +Roughly 100+ mL H2O remains in feces daily.
Term
the 2 major types of motility patterns derived from contractions in the small intestine
 Definition
-Peristalsis
-Segmentation
Term
Peristalsis
 Definition
-Movement of chyme through the small intestine.
-Slow and weak movement – avg. 1 cm/min.
[image]
Term
Segmentation
 Definition
-Major contractile activity of the small intestine 2-3x/min.
-Strong contraction of circular smooth muscle to mix chyme.
-this is to mix the contents; these muscles can squish forward, backwards, up, and down
[image]
Term
some ways by which humoral regulation of intestinal activity is done
 Definition
-Endocrine regulation
-Paracrine regulation
Term
some things secreted by the enterocytes for endocrine regulation of intestinal activities
 Definition
-Secretin
-Cholecystokinin (CCK), a.k.a. pancreazymin
-Gastric inhibitory peptide or glucose-dependent insulinotropic peptide (GIP)
-Motilin
Term
how paracrine regulation of the intestinal activities is done
 Definition
filling --> ↑ intestinal pressure --> ↑ secretion of serotonin (ECL cells) in intestinal mucosa --> ↑ muscle contractions
Term
Secretin
 Definition
stimulus: drop in pH. -Stimulates HCO3- and H2O secretion in pancreatic juice. -Inhibits gastrin secretion.
Term
Cholecystokinin (CCK), a.k.a. pancreazymin
 Definition
stimulus: presence of partially digested fats and proteins. -Stimulates contraction of gallbladder, thus secretion of bile. -Stimulates enzymatic and HCO3- secretion in pancreatic juice.
Term
Gastric inhibitory peptide or glucose-dependent insulinotropic peptide (GIP)
 Definition
stimulus: proteins, fats, CHOs.
-Stimulates insulin secretion from endocrine pancreas.
-Inhibits gastric motility & HCl secretion --> slows emptying.
Term
Motilin
 Definition
released from M cells during fasting --> stimulates motility
Term
the parts of the small intestine in order
 Definition
cecum --> ascending colon --> transverse colon --> descending colon --> sigmoid colon --> rectum --> anal canal --> anus
[image]
Term
how motility occurs in the large intestine
 Definition
Outer surface bulges outward to form haustra (bag-like structure).
1) Haustrations
2) Mass propulsive movements.
[image]
Term
haustra
 Definition
part of the outer surface of the large intestine that bulges outward to form a bag-like structure
[image]
Term
haustrations
 Definition
mixing movements in the large intestine triggered by chyme
Term
the histological makeup of the large intestine
 Definition
-No plicated folds or villi.
-Thin brush border on epithelial cells.
-Many goblet cells.
[image]
Term
absorbing colon
 Definition
roughly the 1st half of the colon -H2O (most of remaining 10-15%) and electrolytes (Na+, Cl-). -HCO3- secreted to neutralize acidic products of bacterial metabolism. -Production of vitamin B complexes and vitamin K via microbes.
Term
storage colon
 Definition
roughly the 1st half of the colon -Feces with residual H2O
Term
what the microbes in the absorbing colon do
 Definition
-make vitamin K and some B vitamins (riboflavin, thiamin, biotin, pantothenic acid, folic acid) -make short-chain fatty acids (FAs) from cellulose +FAs help absorb Na+, Ca2+, HCO3-, Mg2+, Fe2+ (much less absn. in colon vs. SI). -Beneficial (mutualism) vs. harmful species of bacteria
Term
diversity of microbes in the large intestine
 Definition
> 400 different species of microbes
Term
Disruption of normal microflora leads to...
 Definition
irritable bowel disease
Term
what causes the defecation reflex?
 Definition
Waste material passes to the rectum
Term
the amount of your feces that's composed of bacteria
 Definition
about 30%
Term
the pathway of the defecation reflex
 Definition
Distension of rectum by fecal material --> signals sent to the sacral region of the spinal cord --> induction of defecation reflex --> relaxation of internal anal sphincter (involuntary) and external anal sphincter (voluntary), aided by contractions of abdominal and pelvic muscles which push feces from rectum --> defecation
[image]
Term
why the defecation reflex is called a reflex
 Definition
because part of it goes through the spinal cord and back without going to the brain
[image]
Term
some functions of the liver
 Definition
[image]
Term
largest internal organ
 Definition
liver
Term
why the liver is so good at regenerating
 Definition
Active hepatocytes undergo mitosis --> amazing regenerative abilities
Term
some groups of blood vessels in the liver
 Definition
-hepatic artery
-hepatic portal system
-hepatic veins
[image][image]
Term
Hepatic artery
 Definition
-brings oxygenated blood to liver
-Branches off aorta
[image][image]
Term
Hepatic portal system
 Definition
-brings nutrients and deoxygenated blood from abdominal organs to liver
-Venous return for the abdominal organs
[image][image][image]
Term
hepatic veins
 Definition
multiple hepatic veins take deoxygenated blood from liver to inferior vena cava
[image][image]
Term
depiction of how the hepatic portal system works
 Definition
[image]
Term
why the liver is organized the way it is
 Definition
Organized to filter the blood. Blood percolates through endothelium-lined sinusoids between cords or plates of hepatocytes into the central vein, which then drains into the hepatic vein.
Term
how the liver is organized
 Definition
Lobes --> lobules --> hepatic cords or plates --> hepatocytes
[image]
Term
the histology of the lobule
 Definition
[image]
Term
portal triad in the liver
 Definition
corners at the liver's lobules where the branches of hepatic artery, portal vein, and bile ductules run together
[image]
Term
after the portal triad, the fluid empties into the...
 Definition
central vein, which leads to the bile duct
[image]
Term
Perimeter of each lobule is defined by...
 Definition
portal triads at the corners
Term
the direction everything flows in the portal triad
 Definition
[image]
Term
the flow of oxygen-rich and nutrient-rich blood in the portal triad
 Definition
Oxygen-rich blood from hepatic artery and nutrient-rich blood from hepatic portal vein mix and flow through sinusoids toward central vein in center of each lobule.
[image]
Term
one advantage of the liver's endothelium being fenestrated
 Definition
hepatocytes directly exposed to blood
-this makes it easier for hepatocytes to secrete albumin into the blood stream
Term
the flow of bile through the bile canaliculi in the portal triad
 Definition
collect waste products --> flow in opposite direction (away from central vein) to bile ductules in portal triads --> gall bladder
[image]
Term
bile canaliculi
 Definition
part of the portal triad
-collect waste products --> flow in opposite direction (away from central vein) to bile ductules in portal triads --> gall bladder
[image]
Term
how bile secretion is triggered, and then occurs
 Definition
Bile stored in gall bladder until signaled to release:
-Cholecystokinin – primary signal
-Parasympathetic and enteric nervous system (ACh)
[image]
Term
Cholecystokinin
 Definition
primary signal for bile secretion
[image]
Term
Enterohepatic (re)circulation
 Definition
95% of bile from ileum reabsorbed --> portal vein --> reused
-whatever doesn't get recirculated winds up in the stool
[image]
Term
Bile
 Definition
a collective term, it contains -bile acids -bile salts -Bile pigment – bilirubin (heme without Fe) -Electrolytes -cholesterol -HCO3- -water [image]
Term
Bile acids and bile salts
 Definition
-Precursor – cholesterol.
-Aids digestion of fat.
[image]
Term
Bile pigment aka bilirubin
 Definition
heme without Fe
-Aged RBC --> engulfed by phagocytes mainly in spleen and bone marrow --> … --> liver --> conjugated bilirubin.
[image]
Term
Jaundice or icterus caused by...
 Definition
↑ in blood bilirubin levels
[image]
Term
endocrine functions of the pancreas
 Definition
Islets of Langerhans secrete...
-insulin
-glucagon
-somatostatin
Term
exocrine and digestive function of pancreas
 Definition
pancreatic juice secreted from acinar cells in acini --> pancreatic ducts. -*Contains H2O, HCO3- and digestive enzymes. -Complete digestion of food requires action of both pancreatic and brush border enzyme.
Term
some things that signal for pancreatic juice to be released
 Definition
-Secretin
-Cholecystokinin
-Parasympathetic and enteric nervous systems (ACh)
Term
Most pancreatic enzymes are produced as...
 Definition
inactive precursors called zymogens
Term
Trypsin
 Definition
(when activated by enterokinase in the small intestine)
-triggers the activation of other pancreatic enzymes
-breaks peptide bonds within the aino acid chain
Term
Pancreatic trypsin inhibitor
 Definition
inhibits activation of trypsin in the pancreas
Term
the 3 main enzymes that the pancreas secretes
 Definition
-trypsin
-lipase
-amylase
Term
depiction of the duct of the pancreas that releases enzymes
 Definition
[image]
Term
enterokinase
 Definition
the enzyme that activates trypsinogen into trypsin
[image]
Term
what would happen if the pancreas did not use trypsin inhibitor?
 Definition
trypsinogen could possible turn into trypsin while still in the pancreas
Term
lipase
 Definition
removes FAs from glycerol
Term
Amylase
 Definition
breaks down starch
Term
the role of bicarbonate in the small intestine
 Definition
helps neutralize gastric acid to prevent gastric acid reflux back into the pancreatic ducts
Term
some types of regulation that regulate the digestive system
 Definition
-neural regulation
-hormonal regulation
Term
differences between neural and hormonal regulation of the digestive system
 Definition
-neuronal occurs faster and lasts shorter
-hormonal occurs slower and lasts longer
Term
extrinsic component of the neuronal regulation of the GI activity
 Definition
neuronal input
Term
how the extrinsic parasympathetic component of the nervous system regulates GI activity
 Definition
–generally stimulatory
–vagus nnerves and sacral nerves
Term
how the extrinsic sympathetic component of the nervous system regulates GI activity
 Definition
generally inhibitory (inhibits peristalsis and secretion, stimulates contraction of sphincters)
Term
intrinsic division of the neuronal regulation of the GI system
 Definition
domain of the enteric nervous system (enteric or visceral brain)
Term
Submucosal & myenteric plexi
 Definition
where extrinsic and intrinsic divisions of neuronal regulation of the GI system meet
[image]
Term
depiction of the enteric nervous system (ENS), showing the sympathetic and parasympathetic divisions
 Definition
[image]
Term
Sensory afferent neurons
 Definition
input to ENS, ANS, brain
[image]
Term
Myenteric or Auerbach’s plexus
 Definition
between longitudinal and circular smooth m. – controls GI movements.
-innervates smooth m. of muscular layer from esophagus thru entire GI tract.
(1) ↑ tone (tonic)
(2) ↑ intensity of contractions (phasic)
(3) ↑ rate of contractions (phasic)
(4) ↑ conduction rate of excitatory waves.
[image]
Term
Submucosal or Meissner’s plexus
 Definition
within submucosa – controls GI secretions and local blood flow.
-in SI and LI.
-Innervates mucosal layer.
-Controls local secretion, local absorption, and local contraction of muscularis mucosa.
[image]
Term
Autonomic nervous system (ANS)
 Definition
mainly works through influencing ENS neurons.
[image]
Term
tonic firing of neurons
 Definition
maintaining tone over time
Term
phasic firing of neurons
 Definition
briefer, short-term changes in firing of neurons
Term
types of smooth muscle electrical activity in the GI system
 Definition
(1) Slow Waves
(2) Spike Potentials
Term
Slow Waves
 Definition
not action potentials
-Interstitial cells of Cajal pacemakers.
-Slow, rhythmic, low intensity gradually bring smooth muscle to threshold.
[image][image]
Term
Spike Potentials
 Definition
action potentials
-Slow waves that reach approx. – 40 mV.
-Last longer than neuronal APs.
-Stretch and parasympathetic NS trigger depolarization.
-Sympathetic NS triggers hyperpolarization.
[image][image]
Term
some details about how neural regulation of peristalsis occurs
 Definition
-Presence of food bolus induces contraction and relaxation simultaneously in the same muscle bundles.
-Stretch triggers mechanoreceptors.
-Potential role for chemoreceptors.
[image][image]
Term
the pathway by which neural regulation of peristalsis occurs
 Definition
Stretch triggers mechanoreceptors. Potential role for chemoreceptors. Afferent sensory neurons --> Cholinergic interneurons in ENS --> ACh triggers release of ACh and substance P proximal to bolus --> smooth muscle contraction behind bolus.
-ACh triggers release of NO, VIP, and ATP distal to bolus --> smooth muscle relaxation in front of the bolus.
[image][image]
Term
some short reflexes within the GI tract mediated by ENS
 Definition
-Gastroileal reflex
-Ileogastric reflex
-Intestino-intestinal reflex
[image]
Term
Gastroileal reflex
 Definition
↑ gastric activity --> ↑ motility of ileum --> ↑ movement of chyme through ileocecal sphincter.
[image]
Term
Ileogastric reflex
 Definition
↑ distension of ileum --> ↓ gastric motility.
[image]
Term
Intestino-intestinal reflex
 Definition
↑ distension in one GI segment --> relaxation throughout the rest of intestine.
[image]
Term
Long reflexes in the GI system
 Definition
involve communication through CNS to mediate ENS function.
[image]
Term
table summarizing the GI hormones
 Definition
[image]
Term
some GI hormones you should not forget
 Definition
-ghrelin
-somatostatin
Term
endocrine mediators target...
 Definition
-epithelial cells
-smooth muscle
Term
Paracrine mediators target...
 Definition
-epithelial cells
-neurons
Term
some paracrine mediators involved in the GI system
 Definition
-histamine
-serotonin
Term
sequence of how carbohydrates get digested
 Definition
-Salivary amylase – begins starch digestion.
-Pancreatic amylase – digests starch to oligosaccharides.
-Brush border enzymes – hydrolyzes oligosaccharides into monosaccharides.
[image]
Term
Salivary amylase
 Definition
begins starch digestion.
[image]
Term
Pancreatic amylase
 Definition
digests starch to oligosaccharides.
[image]
Term
Brush border enzymes
 Definition
hydrolyzes oligosaccharides into monosaccharides.
[image]
Term
the carbohydrates that get absorbed
 Definition
only monosaccharides, such as...
-Glucose
-galactose
-fructose
[image]
Term
how glucose is absorbed
 Definition
-by secondary active transport -co-transporting glucose with Na+. [image]
Term
Absorbed monosaccharides goes to...
 Definition
blood (via portal vessel to the liver).
[image]
Term
GLUT2
 Definition
the transporter through which glucose exits enterocytes to interstitial fluid
-this is facilitated transport
[image]
Term
lactose intolerance caused by...
 Definition
lactase insufficiency
Term
Digestion of proteins begins in the stomach when...
 Definition
pepsin digests proteins to form polypeptides.
Term
how digestion of polypeptides occurs in the duodenum and jejunum
 Definition
-Endopeptidases cleave peptide bonds in the interior of the polypeptide
-Exopeptidases cleave peptide bonds from the ends of the polypeptide
[image]
Term
how digestion of polypeptides occurs in the enterocytes
 Definition
Di- and tripeptides --> amino acids.
[image]
Term
Endopeptidases
 Definition
-in the duodenum and jejunum
-cleave peptide bonds in the interior of the polypeptide
+Trypsin
+chymotrypsin
[image]
Term
Exopeptidases
 Definition
-in the duodenum and jejunum
-cleave peptide bonds from the ends of the polypeptide
+Carboxypeptidases
+aminopeptidases
[image]
Term
the endopeptidases in the duodenum and jejunum
 Definition
-Trypsin (pancreatic)
-chymotrypsin (pancreatic)
[image]
Term
the exopeptidases in the duodenum and jejunum
 Definition
-Carboxypeptidases (pancreatic)
-aminopeptidases (brush-border)
[image]
Term
aminopeptidase
 Definition
-cleaves proteins at the amino end
-brush border enzyme in the duodenum and jejunum that helps digest polypeptides.
-The other 3, trypsin, chymotrypsin, and carboxypeptidase, are pancreatic.
[image]
Term
carboxypeptidase
 Definition
-pancreatic enzyme in the duodenum and jejunum
-cleaves proteins at the carboxy end
[image]
Term
how proteins are absorbed
 Definition
1: free amino acids absorbed by co-transport with Na+ (secondary active transport) 2: Di-peptides and tri-peptides transported by secondary active transport using a H+ gradient to transport them into the cytoplasm 3: Facilitated transport of amino acids into interstitial fluid --> portal system --> liver. [image]
Term
the result of lipids entering the duodenum
 Definition
Arrival of lipids in duodenum --> ↑ secretion of bile
[image][image]
Term
Functions of bile acids/salts
 Definition
-Emulsification
-Micelle formation
[image][image]
Term
Emulsification
 Definition
forms smaller fat molecules from big fat droplets --> ↑ surface areas for lipid-lipase contact.
[image][image]
Term
Micelle formation
 Definition
transports digested fat in micelles --> move to brush border for absorption.
[image][image]
Term
how digestion of lipids occurs in the small intestine
 Definition
-Pancreatic lipase + colipase --> triglycerides --> fatty acids + monoglycerides.
-Pancreatic phospholipase digests phospholipids into fatty acids.
[image][image]
Term
Pancreatic lipase
 Definition
Pancreatic lipase + colipase --> triglycerides --> fatty acids + monoglycerides.
[image][image]
Term
Pancreatic phospholipase
 Definition
digests phospholipids into fatty acids.
[image][image]
Term
how lipids are transported in the gut
 Definition
micelles
[image][image]
Term
Micelles contain...
 Definition
-bile salts
-free fatty acids
-monoglycerides
-phospholipids
-cholesterol
[image]
Term
the role of micelles in absorption of fat
 Definition
Micelles allow diffusion of constituents through unstirred water layer on enterocytes -> absorption through apical membranes of epithelium.
[image]
Term
what happens to micelles after they enter the cell?
 Definition
Resynthesize triglycerides and phospholipids within cell --> combine with apolipoprotein to form chylomicrons.
[image]
Term
what happens to chylomicrons after they get secreted out of the cell?
 Definition
chylomicrons --> secrete into central lacteals --> larger lymphatic vessels --> thoracic duct --> mix with venous blood at vena cava --> blood circulation
-indirect trip to the liver
[image][image]
Term
general depiction of what happens with micelles and lipids in lipid absorption
 Definition
indirect trip to the liver
[image]
Term
lipoproteins
 Definition
In blood, lipids + apolipoproteins = lipoproteins
Term
Lipoprotein lipase (LPL)
 Definition
hydrolyzes triglycerides --> free fatty acids + glycerol supplied to tissues
Term
what happens to chylomicrons in the bloodstream?
 Definition
In capillary endothelium of adipose tissue, LPL hydrolyzes triglycerides in chylomicrons --> free fatty acids and glycerol to store in the fat cells
Term
what happens to what's left of the chylomicrons after hydrolysis?
 Definition
After hydrolysis, chylomicron remnants containing cholesterol are taken to the liver. Liver synthesizes and adds cholesterol and triglycerides.
Term
Very low-density lipoprotein (VLDL)
 Definition
triglycerides and cholesterol + apolipoproteins leave liver to deliver triglycerides to organs.
Term
how VLDL gets converted to LDL
 Definition
As triglycerides are removed, VLDLs --> intermediate-density lipoprotein (IDL) --> low-density lipoprotein (LDL). ↓ in triglyceride and ↑ in cholesterol and apolipoproteins content.
Term
low-density lipoprotein (LDL)
 Definition
transport cholesterol to organs. “Bad cholesterol.”
[image]
Term
what happens to excess cholesterol?
 Definition
returned to liver on HDL to prevent atherosclerosis
Term
high-density lipoprotein (HDL)
 Definition
Excess cholesterol is returned to the liver on high-density lipoproteins (HDL), thus preventing atherosclerosis. “Good cholesterol.”
[image]
Term
the types of lipoproteins that can be in chylomicrons
 Definition
-VLDL
-IDL
-LDL
-HDL
Term
the lipoproteins with the most triglycerides
 Definition
VLDL
Term
table summarizing the lipoproteins involved in transport of lipids
 Definition
[image]
Term
the structure of a lipoprotein
 Definition
[image]
Term
depiction of the major pathways of lipid metabolism
 Definition
[image]
Term
Arteriosclerosis
 Definition
hardening of arteries
-the most common form is atherosclerosis
[image]
Term
Atherosclerosis
 Definition
the most common form of arteriosclerosis (hardening of the arteries)
[image]
Term
the pathway that leads to atherosclerosis
 Definition
Arterial endothelial cells contain LDL Receptors --> LDL-LDL R’ --> endocytosis --> oxidized LDL --> oxidative damage and inflammatory response --> formation of atheroma --> atherosclerosis [image]
Term
Atheromas
 Definition
localized plaques of fat that protrude into lumen of arteries
[image]
Term
how atheromas clog arteries
 Definition
Atheromas (localized plaques of fat) protrude into lumen of arteries --> ↓ blood flow --> … --> ↑ clot formation
[image]
Term
substances that can reduce the oxidation of LDL
 Definition
Antioxidants, such as vit C, E, and beta-carotene
Term
do arterial endothelial cells contain HDL or LDL receptors?
 Definition
LDL receptors
Term
the pathway explaining what HDL does with cholesterol
 Definition
HDL carries cholesterol to liver --> formation of bile in liver that contains bile salts and cholesterol --> eliminates excessive cholesterol from the body
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