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Chapter 16 (VPHY 3100)
Chapter 16 (VPHY 3100)
218
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]
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