Continuous and intermittent Flow

Question 1

What is the role of elastic arteries

Answer 1

convert the pumping of the heart into continuous blood flow

• dampening the pressure changes
• distribution of blood

Question 2

What is the composition of the elastic arteries

Answer 2

endothelium, elastin, smooth muscle, collagen

Question 3

What is the role of elastin

Answer 3

allows the walls of the arteries to expand as well as storing potential energy for expansion during systole
- allowing all the blood flow to all the tissues that needs the blood and other stuff

Question 4

What is the role of collagen

Answer 4

during diastole, the potential energy would be released to keep the blood flow going on

Question 5

how does the arteries convert the pumping into the continuous flow

Answer 5

1. mid systole - energy used to stretch the walls
2. end of systole, energy stored in elastin
3. mid diastole - energy released during elastin recoil
4. end diastole - elastin return to OG shape

Question 6

What is ABP determined by

Answer 6

in the elastic arteries and is the driving force for the blood flow
-SP AND DP too

Question 7

how to calculate pulse pressure

Answer 7

systolic P - diastolic P

Question 8

how to calculate mean arterial blood pressure

Answer 8

DP +((SP -DP)/3) so aorund 93mmHg

Question 9

What does MAP determine

Answer 9

diffusion of substances across the tissues

Question 10

factors affecting SP, DP, MAP

Answer 10

elastin content, stroke vol and peripheral R

Question 11

factors affecting SP

Answer 11

• SV ejected into the aorta
• aorta distensibility ( how elastic )
• ejection Velocity
• DP of prevoius beat
• contractility

Question 12

factors affecting DP

Answer 12

• arteriolar R - vasoconstriction or dilation
• arterial distensibility
• HR

Question 13

how does ageing have an effect on arterial distensibility

Answer 13

• as the age increases, the it becomes less elastic

Question 14

why does SP increases if the elasticity is reduced

Answer 14

the arteries wont be elastic so it wont recoil therefore, the pressure need to be increases to accommodate the flow

Question 15

why does DP decrease if the elasticity is reduced

Answer 15

less energy is stored in the elastin so when less energy is released too

Question 16

what happens to the SP, DP and MAP during MAP

Answer 16

-SP- increased due to increased SV
-TPR - decreased due to muscles dilation so
DP is decreased
-MAP same for sufficient diffusion

Question 17

how is the alveolar gas composition constane

Answer 17

• the ventilation and the metabolism is matched
• so O2 and CO2 entering and leaving is the same in RS
• this is important so the arterial blood environment is constant too

Question 18

what is the function of capillaires

Answer 18

exchange of substance

Question 19

composition of capillaries

Answer 19

purely endothelium so one cell thick

Question 20

types of capillaries

Answer 20

continous and fenesrated

Question 21

what happens to the CSA and velocity in the capillaries

Answer 21

CSA increases as it branches into smaller ones so the velocity decreases
- flow is slow so the substances can be exchanged

Question 22

forces involved fluid filtration in the capillaries

Answer 22

-capillary hydrostatic P
-interstitial oncotic P
interstitial hydrostaic P
plasma oncotic p

Question 23

work out net filtration?

Answer 23

Kf x(forces favouring filtration ) - (forces favouring reabsorption)

Question 24

how is the fluid filterated and reabsorbed in peripheral capillaries

Answer 24

• the hydrostatic pressure is higher than oncotic P at the arterial end so the fluid leaves
• the hydrostatic P is lower than the oncotic P so the fluid is reabsorbed
• filtration = reabsorption so no net filtration

Question 25

what is the net movement of fluid during vasoconstriction

Answer 25

-net reabsorption because the TPR is increased, leading to lower hydrostatic P

Question 26

what is the net movement of fluid during vasodilation

Answer 26

Net filtration becuase the TPR is lower and the hydrostatic pressure is higher due to less energy being lost