Vascular Function and its control

Question 1

Describe what is the central venous pressure? What is the approximate value?

Answer 1

The pressure in the great veins (IVC, SVC) just outside the heart approximately 1-5mmHg

Question 2

What is the mean circulatory filling pressure dependent on?

Answer 2

the compliance of the vessels

Question 3

most of the blood in the circulation is distributed to which area

Answer 3

systemic veins (65%)

Question 3

What effect on the CO and venous pressure would an increase in contractility result in?

Answer 3

Increased CO and a decrease in venous pressure

Question 4

What are the endothelial products that alter smooth muscle contraction

Answer 4

Nitric oxide (vasodilator) endothelin (vasconstrictor) prostaglandins (sometimes vasodilator and sometimes vasoconstrictor)

Question 5

Is the compliance greater in the veins or arteries?

Answer 5

veins (it is why arterial pressure is more sensitive to changes in volume compared to venous)

Question 6

What does the cardiac function curve tell you?

Answer 6

It describes what happens to cardiac output when venous pressure varies (dependent on F-S relationship)

Question 7

What does increased blood volume/vasoconstriction do to the vascular function curve?

Answer 7

moves the curve up and to the right (will get higher CO for a given venous pressure)

Question 8

What does the vascular function curve tell you?

Answer 8

describes what happens to venous pressure when cardiac output varies (independent of F-S relationship)

Question 10

Describe what is the mean circulatory filling pressure and what is the approximate value

Answer 10

the eventual pressure that will be created when the heart stops and blood settles in the vessels. Blood will move from the arteries into the veins. Approximately 7 mmHg

Question 11

How do you clinically assess the central venous pressure?

Answer 11

Jugular venous pressure

Question 12

What will decreased TPR do to the vascular function curve?

Answer 12

It will increase the CO at low venous pressure but effect wears off to normal by high pressures

Question 13

What effect on the CO and venous pressure would an increase in blood volume cause?

Answer 13

Increased CO and increased Venous pressure

Question 14

What effect on the CO and venous pressure would a decrease in TPR cause?

Answer 14

An increase CO and an increase in venous pressure