Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
10 Cards in this Set
- Front
- Back
|
1) What is the proportionality equation of blood flow? 2) What is the pressure gradient s3 |
1) Proportional to change in pressure/resistance. Inversely proportional to the resistance to flow. 2) The higher the pressure gradient, the higher the fluid flow. P1 (pressure at beginning) - P2 (at end) needs to be positive for blood flow. Only the pressure change is important. |
|
|
1) Where is the greatest blood pressure gradient in blood vessels and how does it change? s6 |
1) Greatest in the aorta decreases as goes through arteries -> arteries -> arterioles -> capillaries -> venules -> veins -> venae cavae Cross sectional area of arteries and then arterioles increases. From venae cavae, blood comes into heart at diastole. |
|
|
1) How does the blood flow in veins work. 2) If resistance increases, flow _______ and vice versa s8,9 |
1) Veins use milking action of muscles to help move blood. Pressure is small in comparison to heart, as valves in veins prevent backflow; when skeletal muscle compress veins, force blood towards the heart (skeletal muscle pump) 2) decreases |
|
|
1) What is Poiseuille's Law? s10 |
1) R = 8Lη/πr4 or R ∝ Lη/r4
8 x length of tube x viscosity of blood / pi x r x 4 Resistance increases as length increases Resistance increases as viscosity increases Resistance decreases as radius increases |
|
|
1) Is the flow rate same as the velocity? What is the equation 2) What is the velocity of flow dependant on? 3) where is the velocity lowest? s12 |
1) No. Flow rate has volume/min units e.g. cm3/min Velocity = Flow rate / Cross sectional area (A) e.g. cm/min 2) depends on total cross sectional area of all the vessels (aorta all the way to venae cavae) -> high velocity at first and decreases as it goes on. 3) Capillaries have most total cross sectional area, so its lowest velocity here. and velocity increases at the veins. |
|
|
1) describe vasoconstriction and vasodilation 2) Why is myogenic autoregulation important? s14 |
1) -> Vasoconstriction: decrease in blood vessel diameter/radius and decreases blood flow. -> Vasodilation: Increase in blood vessel diameter/radius and increases blood flow. 2) Lowering blood vessel pressure to avoid damaging brain or kidney, etc. or increasing pressure when too low |
|
|
1) What are the paracrine effects on arteriolar resistance? s19 |
1) Local chemical way to regulate blood flow
-> Active Hyperemia: When increase in tissue metabolism , releases metabolic vasodilators (stimulators are adenosine, when low O2, high CO2, acidic)into ECF -> arterioles dilate, lowers their resistance, increases blow flow in -> O2 and nutrient supply increases as long as metabolism is increased -> Reactive Hyperemia: When decreased blood flow to tissue due to occlusion (e.g. clot). -> Metabolic vasodilators accumulate in ECF -> arterioles dilate but occlusion still prevent blood flow -> When occlusion removed (mechanically) -> Resistance decreases and blood flow increases -> As vasodilators wash away, arterioles constrict and blood flow returns to normal |
|
|
1) What are the sympathetic control factors? s19 |
1) Brain connected to resistant arterioles by sympathetic nervous system. NE coming out at synaptic clefts onto vascular smooth muscle cells in arterioles. when high sympa, telling skin vessels to close down -> from adrenal medulla: Epinephrine can act on receptors on individual smooth muscle cells to give control -> When increase in activity, NE releases onto alpha receptors (G protein coupled) and as AP signal rate increases, blood vessels constrict. As signal rate decreases, blood vessels dilate. (caused by parasympathetic system) |
|
|
1) What are the chemicals that regulate arteriolar resistance and what do they do |
1) -> NE: baroreceptor reflex -> Angiotensin II: increases BP -> Epinephrine: increase blood flow to skeletal muscle, heart, liver -> Adenosine: increases BP -> the metabolic markers -> Natriuretic peptides: reduce BP |
|
|
1) Which ventricle more important for generating blood pressure gradient. |
1) wall of left ventricle is thicker than that of right ventricle; generating greater force to pump blood to the body. |
