lecture 5: chapter 14/15 Flashcards
where is blood pressure on the circulatory system the highest
in the aorta and largerer arteries
trtue or fals: the pressure stays constant at the aortat
true (relattively contanst)
Why does the pressure drop significantly at the arteriole/capillary junction
They sre area of high resistances
Allows velocity to slow for echange
true or false: the pressure in the systetmoc circulation stays constant throughout the enttire passave
false, it decrases until it is at the lowst velocity and prssure near the capillaries
when the blood returns in the right atrium the pressure is 0 mmHH
true
where are there lower pressure, arteriol orvenous side
venous side
what is perpherial ressitance
the friction between the blood and vessel wall
what is the main determinant of resistance
radius
where is flow faster, larger or smaller vessels
faster in large
explain why a smaller radius means a higher resistance
because there an increased surface area exposed to blood which will increase resistance (look at slie 3 from 14/15)
what is the relationship between resistance and radius
if you increase radius, flow is 16x greater (flow=r4)
Resistamce decreases 4 fold (resistance=1/r4)
what are some ecamples of things that increase resistance
abrupt chagnes in diametter, fatty plaques from atherosceleoriss, braching, or sharp turns
what do abrupt changes in direction, fatty plaquest etc do in tterms of restitsncae
increase resistance and disrup laminar flow and cause turnbeunce flow
what is turbulent flow
irregular fluid motion tthat icreases resistance
explain why people with heart plaque have hypertension
because plaque causes bluid up in arterires with increases resistance and ie need more pressure to overcome
explain laminar flow
during laminar flow all the vectors flow in parallel with the highestt velocity and and least friction in the center of the vessek
what are the 3 main determinatns of resisance
blood viscocity
vessel lengtth
vassel radius
blood is more visouc in whatt season and gender
in men and summer
what is poiseuilles law
flow= (pie)(delta pressure)(radius)^/8nl
what does conductance mean
how easy is is to move blood from point a tob
what is the formular for conductance
1/resistance
what is the problem with circualtion in series
the flow is affected by all resisatnces
where is an area in the body where blood flows in series
in the pulmonary circulation (from heart, to lungs and back to heart)
what is imporant about circulation in parallel
it is imporatnt for how the body regulates where the blood is going in the body
it allows for seperatet resistance paths
what is the difference between Q and F
Q is the flow through the entire circulation
F is the flow through a certain segmaent
what is the formula for flow
q=pressure/resistance
what is the flow through a blood vessel determined by
1) the pressure difference between the two ends of the vessel
2) the resistance of the vessel
if pressure increases (and resistance is constant) what happens to the flow
it increases