Term
| The rate of blood flow to each tissue of the body is almost precisely controlled in relation to what? |
|
Definition
|
|
Term
| When tissue is metabolically active, it needs more __ and therefore more blood supply than when at rest. |
|
Definition
|
|
Term
| When a tissue is metabolically active it can have needs up to __X than when at rest. |
|
Definition
|
|
Term
| The heart is only able to increase CO up to _X. |
|
Definition
|
|
Term
| Since tissues can sometimes need blood supply up to 30X than at rest, and CO can only go up 7X, simply increasing blood flow to every tissue is __ sufficient to meet demand. |
|
Definition
|
|
Term
| Local Stimuli (name 2) trigger local responses in vessels (name 2) to control local blood flow precisely to meet demands. |
|
Definition
02 and CO2 Levels
Dilation or constriction |
|
|
Term
| Controlled mainly by the sum of all the local tissue flows. |
|
Definition
|
|
Term
| The heart pumps out what is returned to it from the _ through _. |
|
Definition
|
|
Term
| __ is an automatic response, but it can be augmented by the nervous system to adjust the total output. |
|
Definition
|
|
Term
| Arterial pressure regulation is generally __ of either local blood flow control or CO control. |
|
Definition
|
|
Term
| Name 3 factors that actually control the arterial pressures. |
|
Definition
Reflexes
Autonomics
Renal Regulation |
|
|
Term
| Basically means that your body is putting out what is coming to it. |
|
Definition
|
|
Term
|
Definition
|
|
Term
| The movement of blood; always from high pressure to low pressure. |
|
Definition
|
|
Term
| The quantity of blood that passes a certain point in the circulation in a given time. |
|
Definition
|
|
Term
| Normal blood flow in total circulation in what? |
|
Definition
5L/min (100ml/sec)
This is CO |
|
|
Term
| What is the equation for calculating flow? |
|
Definition
|
|
Term
| The force exerted by the blood |
|
Definition
|
|
Term
| Blood between the 2 ends of a vessel |
|
Definition
| Pressure difference/gradient |
|
|
Term
| A force generated by the heart that pushes blood thru a vessel |
|
Definition
|
|
Term
| Difference of pressures is not an absolute pressure? why? |
|
Definition
| Because if pressure at both ends of a vessel is 100 mmHg, then the pressure difference is 0. So there will be no blood flow. |
|
|
Term
| What unit is pressure almost always measured in? |
|
Definition
|
|
Term
| Impediment to blood flow thru the vessel. |
|
Definition
|
|
Term
| The measure of friction that impedes flow. |
|
Definition
|
|
Term
| Results from friction between blood and intravascular endothelium that lines the inside of the vessel. |
|
Definition
|
|
Term
| Name 5 factors that influence resistance. |
|
Definition
1. Diameter of tube
2. Length of tube
3. Peripheral Resistance Unit
4. Total Peripheral Resistance
5. Effect of pressure |
|
|
Term
| If you incease the diameter of a tube, what happens to resistance? |
|
Definition
|
|
Term
| If you decrease tube diameter, then resistance __ |
|
Definition
|
|
Term
| If you increase the length of a tube, what happens to resistance? |
|
Definition
|
|
Term
| Decreased length of tube = __ resistance |
|
Definition
|
|
Term
| The calculation from flow and pressure difference measurements |
|
Definition
| Peripheral Resistance Unit (PRU) |
|
|
Term
| The (R) for the entire systemic circulation |
|
Definition
| Total Peripheral Resistance (TPR) |
|
|
Term
| Normal flow is approximately how many ml/sec? |
|
Definition
|
|
Term
| The change in P between systemic arteries and systemic veins is approximately what? |
|
Definition
|
|
Term
| Normal flow is approximately how many ml/sec? |
|
Definition
|
|
Term
| Decreased hematocrit does what to viscosity? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| Increased viscosity does what to resistance? |
|
Definition
|
|
Term
| Decreased resistance does what to flow? |
|
Definition
|
|
Term
| When vessels become strongly constricted, then the change in pressure __, so TPR __ |
|
Definition
|
|
Term
| When vessels dilate, what happens to TPR? |
|
Definition
|
|
Term
| What is the effect of pressure on vascular resistance? |
|
Definition
| Increase is pressure is usually autoregulated and controlled for in vascular beds, so it does not result in a proportionate increase in flow. |
|
|
Term
| The measure of blood flow thru a vessel for a given change in P. |
|
Definition
|
|
Term
| The inverse of resistance |
|
Definition
|
|
Term
| The amount of pressure required to force whole blood thru a vessel as compared to water. |
|
Definition
|
|
Term
| Whole blood normal viscosity is about what? |
|
Definition
| 3=3X more pressure needed to force blood thru a vessel as water |
|
|
Term
| Blood plasma viscosity is about what? |
|
Definition
|
|
Term
| How does hematocrit effect viscosity? |
|
Definition
| Viscosity of blood increases drastically as hematocrit increases (polycythemia) and flow is then decreased |
|
|
Term
| What is another factor, besides hematocrit, that affects viscosity? |
|
Definition
| Plasma protein concentrations and types |
|
|
Term
| The amount a vessel can accommodate in increase in pressure by increasing volume within the vessel. |
|
Definition
| Vascular Distensibility (Compliance) |
|
|
Term
| The ability of a vessel to stretch when blood volume is increased |
|
Definition
| Distensibility (Compliance) |
|
|
Term
| Are arteries or veins more compliant? |
|
Definition
| Veins, b/c arteries are thicker |
|
|
Term
| Transports blood under high pressure |
|
Definition
|
|
Term
| Have strong vascular walls due to blood flowing at high velocities |
|
Definition
|
|
Term
| Function as low-resistance conduits and as pressure reservoirs |
|
Definition
|
|
Term
| Maintain blood flow to the tissues during ventricular relaxation |
|
Definition
|
|
Term
| What is the formula for compliance? |
|
Definition
|
|
Term
| Because blood pumps continually into the aorta, pressure in the aorta is continually high, averaging about __mmHg. |
|
Definition
|
|
Term
| Because the heart pumping is pulsatile, the systemic arterial pressure alternates between __ (systolic) and __ (diastolic) |
|
Definition
120 (systolic)
80 (diastolic) |
|
|
Term
| Pulmonary artery systolic is __ and diastolic is __ |
|
Definition
|
|
Term
| The max arterial pressure at the peak of systole (120 is normal) |
|
Definition
|
|
Term
| The min arterial pressure during diastole (80 is normal) |
|
Definition
|
|
Term
| Systolic/Diastolic (120/80 is normal) |
|
Definition
|
|
Term
| Systolic - Diastolic (40 is normal) |
|
Definition
|
|
Term
| What is the formula for Mean Arterial Pressure (MAP)? |
|
Definition
|
|
Term
| The average of the arterial pressure measured millisecond by millisecond over a period of time. |
|
Definition
|
|
Term
| MAP is not simply an average of DP and SP because of what? |
|
Definition
| More time is spent in diastole during the cardiac cycle than systole |
|
|
Term
| A homeostatic adjustment to MAP in the short term (seconds to hours) |
|
Definition
|
|
Term
| Can cause dilation or constriction of vessels as necesary, like whant arterial pressures change. |
|
Definition
|
|
Term
| Name the primary atrial baroreceptors |
|
Definition
2 carotid sinuses (head)
Aortic arch (heart) |
|
|
Term
| Proportional to MAP and PP |
|
Definition
| Firing rate of baroreceptors |
|
|
Term
| Why is homeostasis so important in the head? |
|
Definition
| Because the head does not have room for much constriction or dilation of vessels to occur |
|
|
Term
| This atrial baroreceptor has symp and para symp innervation from Dorsal Vagal Nuclei |
|
Definition
|
|
Term
| Name 3 other places in which other baroreceptors are located? |
|
Definition
Large systemic veins
Pulmonary vessels
Walls of the heart |
|
|
Term
| Short term regulators of arterial pressure but adapt to a maintained change in pressure. |
|
Definition
|
|
Term
| What is the most important long term regulator of arterial pressure? |
|
Definition
|
|
Term
| Walk thru the Medullary Cardiovascular Center (Doral Vagal nuclei) |
|
Definition
| Increased P = Increased Firing = Increased PSNS output / decreased SNS = decreased CO and TPR = decreased MAP |
|
|
Term
| The smallest branches of the arterial system, act as control conduits thru which blood is released into capillaries. |
|
Definition
|
|
Term
| The dominant site of resistance to flow in the vascular system |
|
Definition
|
|
Term
| Have a major role in determining MAP and in distributing flow to organs and tissues |
|
Definition
|
|
Term
| Since MAP is identical throughout the body, __ use vasodilation and vasoconstriction of smooth muscle walls to alter resistance to flow. |
|
Definition
|
|
Term
| Function as conduits for transport of blood back to the heart |
|
Definition
|
|
Term
| Low resistance conduits for venous return |
|
Definition
|
|
Term
| Very compliant and contain most of the blood in the vascular system: serve as a major reservoir of extra blood. |
|
Definition
|
|
Term
| Name 3 determinants of venous pressure |
|
Definition
SNS
Skeletal Muscle Pump & Respiratory pump
Venous Valves |
|
|
Term
| Causes vasoconstriction to maintain pressure and venous return |
|
Definition
|
|
Term
| Increase venous pressure locally and enhance venous return by contraction fo muscles. |
|
Definition
| Skeletal muscle and respiratory pump |
|
|
Term
| Allow pressure to produce flow toward the heart. Prevents backward flow. |
|
Definition
|
|
Term
| Small vessels that collect blood from capillaries and gradually coalesce as veins |
|
Definition
|
|
Term
| Pressure in the right atrium because all venous blood flows into the right atrium. |
|
Definition
| Right Atrial Pressure (Cenral Venous Pressure) |
|
|
Term
| What is normal Right Atrial Pressure? |
|
Definition
|
|
Term
| Right atrial pressures are regulated by a balance between what? |
|
Definition
| The ability of the heart to pump blood out of the right atrium and ventricle into the lungs and the tendency of blood to flow in from peripheral veins into the right atrium |
|
|
Term
| What elevates right atrial pressure? |
|
Definition
|
|
Term
| What decreases right atrial pressure? |
|
Definition
|
|
Term
| Rapid inflow of blood into the right atrium increases right atrial pressure. Venous return can be increased by what 3 things? |
|
Definition
1. Increased BV
2. Increased Peripheral Venous Pressures
3. Dilation of arterioles, which decreases peripheral resistance and allows rapid flow of blood from the arteries to the veins |
|
|
Term
| What was dilation of arterioles do to blood flow? |
|
Definition
|
|
Term
| Normal right artrial pressure is 0 mmHg, which is equal to what? |
|
Definition
| Atmospheric pressure around the body |
|
|
Term
| What are the lower limits of right atrial pressure? |
|
Definition
|
|
Term
| What would happen if right atrial pressure were to rise to 4 to 6 mmHg? |
|
Definition
| Blood would begin to back up into the large veins. This would enlarge veins, and even normal collapse points will open up. As P continues to rise, peripheral venous pressure rises too |
|
|
Term
| Name 3 normal collapse points? |
|
Definition
over 1st rib
Axilla
Root of neck |
|
|
Term
| A key determinant of peripheral venous pressures |
|
Definition
|
|
Term
| Pressure in the peritoneal cavity |
|
Definition
|
|
Term
| What is normal intraabdominal pressure? |
|
Definition
|
|
Term
| Intraabdominal pressures can rise to 15-30 mmHg, as a result of what 4 things? |
|
Definition
Pregnancy
Large Tumors
Abdominal Obesity
Excessive Fluid |
|
|
Term
| Why is P in the legs always at least equal to P in the intraabdominal cavity? |
|
Definition
| Because when intraabdominal pressure rises, pressure in the veins have to rise above it before the veins will open and allow blood to flow from the legs to the heart. |
|
|
Term
| Caused by the weight of blood within the vessels. |
|
Definition
|
|
Term
| When standing, right atrial pressure remains zero because the heart pumps into the arteries any excess blood that attempts to accumulate. This is due to what? |
|
Definition
|
|
Term
| Due to gravitational pressures, when a person is standing and absolutely still, the pressure in the veins at the feet is about __ mmHg because of the graviational weight of the blood in the veins between the heart and the feet. |
|
Definition
|
|
Term
| Veins of the neck have 0 pressure and __ when standing upright. If pressure rises above 0 then the veins __ which causes blood to flow and drives P back down to 0. |
|
Definition
|
|
Term
| These veins have negative pressure and are not collapsable because of their attachment to the bony skull. |
|
Definition
|
|
Term
| Does gravitational pressure apply to veins only? |
|
Definition
| no they apply to arteries and arterioles too |
|
|
Term
| MAPs are described at the level of the heart. Pressure at the feet is actually much __ |
|
Definition
|
|
Term
| Work to ensure a one way flow of blood toward the heart |
|
Definition
|
|
Term
| With any movement of tension of skeletal muscle within the legs, veins are __ which squeezes blood toward the heart. |
|
Definition
|
|
Term
| Helps to regulate gravitational pressures |
|
Definition
|
|
Term
| With prolonged standing, blood will accumulate in the legs and feet and increase the __ pressure of the capillaries. This will force fluid out of the blood and into the tissues and cause what? |
|
Definition
|
|
Term
| Some valves become incompetent or destroyed. Characterized by large bulbous protrusions of the veins beneath the skin of the entire leg. |
|
Definition
|
|
Term
| Sites where nutrients and waste products are exchanged between blood and tissues. |
|
Definition
|
|
Term
| Main function is to exchange fluids, nutrients, electrolytes, hormones and other substances between the blood and interstitial |
|
Definition
|
|
Term
| Thin walled tubes of endothelial cells one layer thick |
|
Definition
|
|
Term
| Numerous __ pores are permeable to water and other small molecule substances. |
|
Definition
|
|
Term
| Do capillaries have smooth muscle or elastic tissue? |
|
Definition
|
|
Term
| Capillary cells are separated by what? |
|
Definition
|
|
Term
| Can capillaries contract? |
|
Definition
| No because they do not have any smooth muscle |
|
|
Term
| Flow of blood in capillaries is __, turning off and on every few seconds |
|
Definition
|
|
Term
| Constriction of metarterioles and precapillary sphincters |
|
Definition
|
|
Term
| The fact that flow of blood capillaries is intermittent is due to what? |
|
Definition
|
|
Term
| What is the most important factor that regulates vasomotion? |
|
Definition
| 02 concentration in the tissues |
|
|
Term
| Flow increases thru capillaries with an increase in the demand of what? |
|
Definition
|
|
Term
| Blood flow and pressure in capillaries is expressed as __ |
|
Definition
|
|
Term
| What determines the velocity of capillary blood flow? (2) |
|
Definition
1. R of arterioles
2. Number of open capillary sphincters |
|
|
Term
| When capillary sphinters are closed, what happens to blood flow? |
|
Definition
|
|
Term
| Increased resistance does what to blood flow? |
|
Definition
|
|
Term
| The most important means by which substances are transferred between plasma and interstitial fluids |
|
Definition
|
|
Term
| Can diffuse freely thru the membrane across the epithelial wall |
|
Definition
|
|
Term
| Cannot diffuse freely thru membrane, so they diffuse thru pores in the capillaries |
|
Definition
| Water soluble (H20, Na, Cl, glucose) |
|
|
Term
| Some molecules are too large to diffuse thru the pores, name one. |
|
Definition
|
|
Term
| Ions and polar molecules move thru what? |
|
Definition
|
|
Term
| Why do plasma proteins move out of the capillaries very slowly? |
|
Definition
| Because they are large, sometimes too large like albumin |
|
|
Term
| Determined by the need/use/metabolism of a substance in the tissue |
|
Definition
|
|
Term
| Fluid filtration across capillaries is determined why what 2 things? |
|
Definition
| Hydrostatic and colloid osmotic pressure |
|
|
Term
| Pressure that forces fluid out of capillary |
|
Definition
|
|
Term
| Pressure that forces fluid into capillaries if positive and out if negative. |
|
Definition
| Interstitial fluid pressure |
|
|
Term
| Pressure that forces osmosis into capillary |
|
Definition
| Capillary plama colloid osmotic pressure |
|
|
Term
| Pressure that forces osmosis out of capillary |
|
Definition
| Interstitial fluid colloid osmotic pressure |
|
|
Term
| The sum of capillary p, interstitial fluid p, capillary plasma colloid osmotic p, and interstitial fluid colloid osmotic p. |
|
Definition
|
|
Term
| If net filtration pressure is negative, what will happen? |
|
Definition
| There will be fluid absorption from the interstitial spaces |
|
|
Term
| If net filtration pressure is negative, what will happen? |
|
Definition
| There will be fluid absorption from the interstitial spaces |
|
|
Term
| Provides a one-way route for movement of interstitial fluid to the cardiovascular system |
|
Definition
|
|
Term
| Returns the excess fluid and proteins filtered from the blood vessel capillaries. |
|
Definition
|
|
Term
| Lymph flow is driven mainly by what? |
|
Definition
| Smooth muscle action and valves |
|
|
Term
| The collection of lymph in the interstitial fluids |
|
Definition
|
|
Term
| Any factor that increases interstitial fluid pressure also increases lymph flow. Name 4 factors. |
|
Definition
1. Elevated capillary hydrostatic pressure
2. Decreased plasma colloid osmotic pressure
3. Increased plasma colloid osmotic pressure
4. Increased permeability of the capillaries |
|
|
Term
| Achieved by rapid changes in local vasodilation or vasoconstriction of the arterioles, metaarterioles, and precapillary sphincters. |
|
Definition
|
|
Term
| Acute control occurs within seconds to minutes to provide very rapid maintenance of what? |
|
Definition
|
|
Term
| Increase in __ metabolism = increase in blood flow. |
|
Definition
|
|
Term
| Increased blood flow due to increased activity |
|
Definition
|
|
Term
| Increased bloow flow in reaction to lack of flow |
|
Definition
|
|
Term
| Tissue metabolism is mainly driven by demand for O2 in the tissues. There are 2 theories that prevail as to the mechanisms: |
|
Definition
1. Vasodilator theory
2. Oxygen (nutrient) lack theory |
|
|
Term
| Theory that states that a decrease in O2 increases formation of vasodilator substances. Leads to increase in blood flow. |
|
Definition
|
|
Term
| This theory states that a lack of oxygen prevents muscle contraction, so vessels would naturally dilate |
|
Definition
| Oxygen (nutrient) lack theory |
|
|
Term
| The vasodilator theory states that a decrease in O2 increases formation of vasodilator substances. Name 4 of those substances. |
|
Definition
1. Adenosine
2. CO2
3. Histamine
4. K+ and H+ ions |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| Slow, controlled changes in flow over a period of days, weeks, or even months. |
|
Definition
|
|
Term
| Provide even better control of the flow in proportion to the needs of the tissues. Occur as a result of an increase or decrease in the physical sizes and numbers of actual blood vessels supplying the tissues. |
|
Definition
|
|
Term
|
Definition
|
|
Term
| Occurs in response to prolonged O2 availability and metabolic demands of the tissue |
|
Definition
|
|
Term
| Control of the circulation by substances secreted or absorbed into the body fluids such as hormones or locally produced factors. |
|
Definition
|
|
Term
| Name 4 vasoconstrictor agents |
|
Definition
1. Norepi
2. Epi
3. Angiotensin II
4. Vasopressin |
|
|
Term
| Name 2 vasodilator agents |
|
Definition
1. Bradykinin
2. Histamine |
|
|
Term
| Increase in Ca++ causes vaso___ due to general effect on smooth muscle contraction |
|
Definition
|
|
Term
| Increase in K+ causes vaso___ due to inhibition of smooth muscle contraction |
|
Definition
|
|
Term
| Increase in magnesium causes powerful vaso__ due to smooth muscle inhibition |
|
Definition
|
|
Term
| Increase in hydrogen ions (decreased pH) causes ___ of the arterioles. Conversely, slight decrease causes ateriolar ___ |
|
Definition
|
|
Term
| Increase in CO2 causes moderate vaso___ most tissues but marked vaso__ in the brain. |
|
Definition
|
|
Term
| Increased CO2 in the blood acts on brain vasomotor center and has an extremely powerful indirect effect transmitted via ___. It causes widespread vasoconstriction throughout the body. |
|
Definition
|
|
