L07: Aterial Vessels And Haemodynamics

Question 1

What is the function of elastic arteries

Answer 1

Determine ABP

Question 2

Give an example of an elastic artery

Answer 2

Aorta

Question 3

What are the 2 function of elastic arteries

Answer 3

1) Dampen the pulsatile flow of blood in aorta so continuous flow occurs in the rest of the circulation
2) level of arterial pressure is maintained in the aorta at diastole

Question 4

What does ejection of blood into the aorta result in

Answer 4

A pressure wave

Question 5

What is the maximum pressure developed in systole

Answer 5

120 mmhg

Question 6

What is the minimum value of pressure in diastole

Answer 6

80 mmhg

Question 7

What is the difference in systolic and diastolic pressure

Answer 7

Pulse pressure

Question 8

What is mean abp

Answer 8

Time average value that takes into account that arterial pressure rises and falls throughout cardiac cycle

Question 9

What happens to the walls of the aorta when it receives blood from the ventricle

Answer 9

Expand to maintain blood pressure

Question 10

What happens to the walls of the aorta during diastole

Answer 10

Walls recoils

Question 11

What does the recoiling of the aortic walls do to the blood

Answer 11

Propel it forward

Question 12

How does the blood become propelled during recoiling

Answer 12

Energy is released that was stored during systole

Question 13

What is the effect of blood propelling forward called

Answer 13

Windkessel effect

Question 14

What does the windkessel effect enable

Answer 14

Continuous blood flow even during diastole

Question 15

Which type of vessel has the greatest pressure change as it enters to another vessel type

Answer 15

Arterioles

Question 16

What are another name for arterioles

Answer 16

Resistance vessels

Question 17

What happens to elastic arteries as you age

Answer 17

Elastic properties degenerate

Question 18

What does degeneration of elastic properties in elastic vessels mean in terms of pressure

Answer 18

Lower diastolic pressure

Question 19

Why is there a lower diastolic pressure when there is a loss of elastic

Answer 19

Reduced elastic recoil

Less blood propelled, less blood volume, less blood pressure

Question 20

What is the loss of elasticity with age known as

Answer 20

Arteriosclerosis

Question 21

When does blood flow

Answer 21

When there is difference in pressure

Question 22

Why do we need pressure for flow to occur

Answer 22

To overcome resistance

Question 23

Is flow equal to resistance or irreversible to resistance

Answer 23

Irreversible

Question 24

What is resistance determined by

Answer 24

Length
Blood viscosity
Radius

Question 25

What happens to the resistance as length of a vessel increases

Answer 25

Resistance increases

Question 26

What happens to resistance as blood viscosity increases

Answer 26

Resistance increases

Question 27

What happens to resistance as radius increases

Answer 27

Resistance decreases

Question 28

What is laminar flow

Answer 28

Flow of blood in most vessels | Blood flows in layers that slip over each other

Question 29

In laminar flow where is the fastest flow found

Answer 29

In the centre

Question 30

In laminar flow where is the slowest flow found

Answer 30

On the sides of the wall

Question 31

What law does the laminar flow follow

Answer 31

Poiseuilles law

Question 32

What is turbulent flow

Answer 32

Ineffienct blood flow

Question 33

When does turbulent flow occur

Answer 33

When flow velocity is high

Question 34

What does the blood flow in turbulent flow cause that we can hear

Answer 34

Vibrations

Question 35

What is the equation for ABP

Answer 35

Cardiac output x TPR

Question 36

If the systolic pressure is the pressure in the aorta during systole, what gives rise to a high systolic pressure

Answer 36

High stroke volume

Question 37

What is systolic pressure determined by

Answer 37

High stroke volume Aortic distensibility Ejection velocity Dystolic pressure of previous beat

Question 38

Therefore when do we get an increased SP

Answer 38

Increased venous return Exercise Ageing

Question 39

What is dystolic pressure determined by

Answer 39

Arteriolar resistance | Heart rate

Question 40

What is arteriolar resistance increased by

Answer 40

Vasoconstriction Arteriosclerosis Atherosclerosis

Question 41

What type of heart rate increases dystolic pressure

Answer 41

Very high

Question 42

Overall what is systolic pressure determined by

Answer 42

Cardiac output

Question 43

Overall what is diastolic pressure determined by

Answer 43

Total peripheral resistance

Question 44

When there is a high TPR what is the diastolic pressure like

Answer 44

High

Question 45

Why is there a high diastolic pressure when there is a high TPR

Answer 45

A high TPR makes it difficult for the blood to run away so pressure is maintained at a higher level so you have more blood/pressure that is detected .

Question 46

Why is there a low diastolic pressure when the TPR is low

Answer 46

A low TPR means the blood can run away easily and less of it is detected and this makes it become a low DP