Systemic Circulation

Question 1

Which has more volume of blood: veins or arteries?

Answer 1

Veins

Question 2

Where are the pressures higher: veins or arteries?

Answer 2

Arteries

Question 3

Where is compliance higher: veins or arteries?

Answer 3

Veins

Question 4

What is the major resistance vessel?

Answer 4

Arterioles

Question 5

Which vessels have the highest pressure drop?

Answer 5

Arterioles

*****

Question 6

What is compliance?

Answer 6

Compliance is the ability of a vessel to expand or give way to stress

Question 7

How do we determine the pressure in blood vessels?

Not calculation

Answer 7

The volume of blood in the vessel and the compliance of the vessel

Question 8

How do you calculate compliance in a vessel?

Answer 8

C= 🔺V
———
🔺P

(delta V over delta P)

Question 9

Does compliance increase or decrease with age?

Answer 9

Decrease

Question 10

What is the transfer of blood from the arteries to the venous circulation during diastole called?

Answer 10

Peripheral runoff

Question 11

What is the peak pressure in the arteries?

Answer 11

The systolic pressure

Question 12

What is the pressure in the arteries just prior to ventricular ejection?

Answer 12

Diastolic pressure

Question 13

How do you calculate pulse pressure?

Answer 13

Systolic Pressure-diastolic pressure

Question 14

How do you calculate MAP?

Answer 14

MAP= DP + 1/3 PP

Approximately

Question 15

What does the elastic recoil of the arterial walls do?

Answer 15

Converts the stored energy into capillary flow during diastole

Question 16

Is flow through the capillaries pulsatile/cyclical?

Answer 16

No, it is pretty constant.

This is due to the elastic recoil of the arterial walls during diastole

Question 17

What maintains blood flow during diastole?

Answer 17

The elastic recoil of the aorta and large arteries

Question 18

Why do we substitute MAP for the 🔺P?

Answer 18

Because 🔺P represents MAP-RAP, and we assume that the pressure in the right atrium is pretty much 0

Question 19

At a constant compliance, what happens to aortic pulse pressure and systolic pressure if you increase stroke volume

Answer 19

Increase

Question 20

If you increase compliance, what happens to pulse pressure and systolic pressure?

Answer 20

They decrease

Question 21

What happens to diastolic pressure if HR increases? Why?

Answer 21

Diastolic pressure increases, because there is less time between beats for the blood to “run off”

Question 22

What will happen to diastolic pressure if you increase TPR/

Answer 22

Diastolic pressure will rise becasue there is more resistance, and less blood will “run off” between beats

Question 23

Does PP increase when you decrease HR? (Remember DP drops when you decrease HR.)
What would happen to PP if you decreased HR and ALSO increased the SV?

Answer 23

PP will not really increase if you decrease HR only.

If you increase SV and also decrease HR, PP will increase

Question 24

What happens to SP if you decrease compliance?

Answer 24

Increases

Question 25

What is stressed and unstressed blood?

Answer 25

Stressed= atrial Unstressed= venous

Question 26

Where is most of your blood: venous or arterial system?

Answer 26

Venous (up to 70%)

Question 27

Can veins contract?

Answer 27

Yes, they have smooth muscle in their walls

Question 28

What are the pressures like in the veins?

Answer 28

Very low pressure 10 mmHg or less usually

Question 29

What happens to the amount of unstressed blood if venomotor tone increases?

Answer 29

The amount of unstressed blood decreases -the veins contracting would cause decreased venous compliance, and therefore, less blood would be in the veins and would then have to be in the arteries Remeber, unstressed blood=blood in the veins Stressed blood=blood in the arteries

Question 30

What happens to the volume of unstressed blood if venomotor tone decreases?

Answer 30

Unstressed volume will increase | More blood will be in the venous/unstressed side since the compliance will increase

Question 31

Are venous return and CO ever different?

Answer 31

No venous return and CO are always equal It’s a closed system duh

Question 32

If you alter CO, what will happen to venous return?

Answer 32

It will be altered in the same way

Question 33

Why does an increase in right atrial pressure decrease atrial filling?

Answer 33

Because the filling of the R atria is due to the pressure difference between the vena cavae and the atrium, and if you increase RAP, 🔺P will decrease= less filling

Question 34

As RAP increases, what happens to CO?

Answer 34

``` CO increases (Due to increased ventricular filling=increased preload) ```

Question 35

What is the mean systemic pressure?

Answer 35

It is the pressure that would be there if the heart was stopped and the blood volume equalized in all spaces

Question 36

If you increase the contractility/inotropicity of the heart by giving something like Digitalis, it will increase CO. How will the venous return respond, and therefore the RAP?

Answer 36

Venous return will also increase RAP will DECREASE**** (this is because more blood is ejected from the heart with each beat, so pressure in the R atrium will decrease)

Question 37

What will happen to RAP and venous return if you decrease cardiac inotropicity/contractility?

Answer 37

CO will decrease, so venous return will also decrease. RAP will increase, since there is less blood being ejected from the heart with each beat*******

Question 38

What happens to mean systemic pressure if you increase blood volume through a blood transfusion?

Answer 38

Increases

Question 39

Would a decrease in venous compliance have the same effect on mean systemic pressure as a blood transfusion?

Answer 39

Yes it would increase

Question 40

What will happen to RAP and Mean Systemic pressure if you increase blood volume?

Answer 40

RAP increases Mean systemic pressure increases

Question 41

What will happen to CO and RAP if you increase blood volume

Answer 41

Both will increase

Question 42

What will happen to venous return if you decrease venous compliance (e.g., constriction of veins)

Answer 42

It will increase****

Question 43

What are the only two things that mean systemic pressure is dependent on?

Answer 43

Volume Compliance (I think)