12/8/2014 Medical Physiology Vascular Control II Amit S. Dhamoon

Question 1

At low preload, SV and CO are?

Answer 1

Low

Question 2

At high preload, SV and CO are?

Answer 2

High

Question 3

As cardiac function goes up, is CO or venous return, central venous pressure does what?

Answer 3

Goes up and then levels off (see notes page 340).

Question 4

Give an example of a pathologic negative inotropic effect, where the CO vs CVP graph shifts downward from normal?

Answer 4

Heart attack, see page 341 in notes.

Question 5

Tachycardia is an example of the body trying to increase CO when it has a decreased ______.

Answer 5

preload.

Question 6

What is the effect of venous vasoconstriction?

Answer 6

The blood normally pooling is mobilized –> venous return increases –> SV increases

Question 7

Preload is the same as:

Answer 7

left ventricular end diastolic volume

Question 8

What is the effect of digitalis?

Answer 8

Increase contractility

Question 9

At steady state, CO = what quantity?

Answer 9

Venous return

Question 10

What three elements of cardiac and vascular function are interdependent?

Answer 10

Cardiac Output
Right Atrial Pressure (same as Central Venous Pressure)
Venous Return
Changes in these quantities are quickly resolved.

Question 11

A transient increase in the right atrial pressure would lead to?

Answer 11

Increase in CO
Decrease in VR
However, since CO > VR, RAP would fall until they were equal again.

Question 12

If VR > CO, what will change to rebalance them?

Answer 12

RAP will increase so CO = VR

Question 13

The cardiovascular system only operates stable when:

Answer 13

CO = VR

Question 14

What is the one parameter that can change both the Starling curve and the VR curve?

Answer 14

TPR (affecting the arterioles)

Question 15

Pulse pressure is determined by:

Answer 15

SV

Question 16

Pulse pressure is proportional to:

Answer 16

SV/C

Question 17

Digitalis is what kind of drug?

Answer 17

Cardiac glycoside

Question 18

What things could elevate the cardiac function curve?

Answer 18

Increase in HR
Increase in SV (increase in CO)
Digitalis

Question 19

Give an example of how sympathetic stimulation could be inhibited.

Answer 19

Anesthesia

Question 20

Give an example of where CO and VR can both increase substantially, but leave RAP (CVP) unchanged.

Answer 20

Exercise. Heart is beating faster, but no change in pressure in right atrium (see page 347 in notes).

Question 21

During exercise, sympathetic ____ increases the mean systemic filling pressure because the blood volume is now contained in a smaller cardiovascular system.

Answer 21

venoconstriction

Question 22

Why does venoconstriction increase mean systemic filling pressure, but not arteriolar constriction?

Answer 22

Because the veins can hold a much larger amount of blood.

Question 23

Spinal anesthesia results in:

Answer 23

inhibited sympathetic drive –> venodilation, lower CVP, lower VR, lower CO.

Question 24

What does spinal anesthesia do to the mean systemic filling pressure?

Answer 24

Lowers it (venodilation)