blood pressure and flow

Question 1

what is compliance?

Answer 1

the ability of an organ to distend in response to applied pressure

Question 2

what is resistance?

Answer 2

the ability to oppose a change

Question 3

what is capacitance?

Answer 3

storing blood volume

Question 4

what are large elastic arteries for? muscular arteries and arterioles? capillaries? veins?

Answer 4

large elastic arteries –> for distribution
muscular arteries and arterioles –> resistance
capillaries –> for exchange
veins –> compliance and capacitance

Question 5

rank the arteries and veins from the one that has the most pressure to least.

Answer 5

aorta>arteries>arterioles>capillaries>venules>veins>vena cava

Question 6

what is the mean aortic blood pressure in a healthy individual?

Answer 6

90 mmHg

Question 7

a 50-70% fall in blood pressure occurs Shen the blood reaches which part of the systemic circulation and why?

Answer 7

when blood reaches arterioles and capillaries because they have a high resistance which means a lower blood pressure

Question 8

what is the mean blood pressure in capillaries?

Answer 8

25-30 mmHg

Question 9

does the pulmonary circulation operate at a lower or higher pressure than the systemic circulation?

Answer 9

lower (eventhough it has similar distribution)

Question 10

what is laminar flow? turbulent flow? and does blood generally exhibit laminar or turbulent flow?

Answer 10

laminar flow: each particle of the fluid follows a straight line without interfering with one another and therefore the velocity is the same at any point
turbulent flow: type of flow that can be seen at branching points of blood vessels or as a result of vascular occlusion.
blood generally exhibits laminar flow

Question 11

vascular endothelial cells lining the interior of blood vessels are influenced by 2 distinct hemodynamic forces. what are they?

Answer 11

shear stress: adhesive force that acts between blood and surface of the blood vessel that may cause damage to vessels
cyclical strain due to pressure across the vessel wall

Question 12

what is shear rate?

Answer 12

rate at which fluid layers move past each other

Question 13

how do you calculate shear stress?

Answer 13

shear stress = shear rate x viscosity of fluid

Question 14

what is vascular resistance?

Answer 14

resistance that must be overcome to maintain blood flow

Question 15

how do you calculate the mean blood pressure?

Answer 15

mean blood pressure = cardiac output x resistance

Question 16

how do we calculate cardiac output?

Answer 16

cardiac output = stroke volume x heart rate

Question 17

what are the receptors that maintains blood pressure within the limits?

Answer 17

baroreceptors

Question 18

where are baroreceptors located?

Answer 18

aortic arch, carotid sinsuses, walls of vena cava and RA

Question 19

what do baroreceptor do to regulate blood pressure?

Answer 19

send impulses to the cardiovascular centre

Question 20

how do you calculate mean systemic arterial pressure ?

Answer 20

mean systemic arterial pressure = cardiac output x total peripheral resistance

Question 21

blood pressure is recorded into two separate measurements. what are they? and when do they occur?

Answer 21

systolic blood pressure occurs during cardiac contraction and diastolic blood pressure occurs between heart beats when the heart is not actively contracting

Question 22

how do you calculate pulse pressure?

Answer 22

pulse pressure = systolic pressure - diastolic pressure

Question 23

what is the windkessel effect?

Answer 23

when blood enters aorta and other elastic arteries faster than it leaves them

Question 24

what happens if arterial compliance decreases?

Answer 24

the windkessel effect decreases and the pulse pressure increases.

Question 25

why are baroreceptors located in the aorta and the carotid arteries?

Answer 25

because its function is to respond quickly to pressure changes and these are highly distensible parts of the vasculature