CHAPTER 25 VENOUS HEMODYNAICS

Question 1

What is intraluminal pressure?

Answer 1

Pressure exerted on the venous wall from WITHIN THE VEINS.

Question 2

What is interstitial pressure?

Answer 2

The pressure exerted on the venous walls from OUTSIDE THE VEINS.

Question 3

What is transmural pressure??

Answer 3

The difference between intraluminal and interstitial pressure.

intraluminal-interstitial = transmural

Question 4

How is transmural pressure related to intraluminal pressure.

Answer 4

Directly

Question 5

What is known as “across the wall” pressure?

Answer 5

Transmural

Question 6

What does transmural pressure determine?

Answer 6

The cross-sectional shape of the veins.

Question 7

Elliptical or dumbbell shape vein has what 3 things?

Answer 7

1. Lower blood volume
2. Lower intraluminal pressure
3. Low transmural pressure

Question 8

Does an elliptical shaped vein have a higher or lower resistance?

Answer 8

Higher resistance

Question 9

A circular shaped vein has what 3 things?

Answer 9

1. higher intraluminal pressure
2. Higher blood volume
3. Higer transmural pressure

Question 10

Does a circular shaped vein higher or lower resisant?

Answer 10

Lower resistant

Question 11

How are volume and transmural pressure related?

Answer 11

directly

Question 12

What does compliance within the veins allow for?

Answer 12

Maintains pressure gradient for blood to flow.

Allows for an increase in blood without an increase in blood pressure.

Question 13

What is hydrostatic pressure?

Answer 13

Pressure within a column of fluid extending from the heart to the level where the pressure is being measured.

Question 14

What is the formula for hydrostatic pressure?

Answer 14

Hp=pgh

Question 15

What is the hydrostatic pressure of a supine individual?

Answer 15

0mmHg

Question 16

What is the hydostatic pressure at the ankles of a standing individual?

Answer 16

100mmHG

Question 17

Above the heart, what is hydrostatic pressure?

Answer 17

Negative

Question 18

In calves with competent venous valves which way will blood flow?

Answer 18

One way, or unidirectional.

Question 19

With an effective calf muscle pump, how much of the blood will be ejected?

Answer 19

> = to 60%

Question 20

In calves with incompetent venous valves, what way will blood flow?

Answer 20

antegrade and retrograde

Question 21

Incompetent valves will have increased what?

Answer 21

1. pressure
2. pooling

Question 22

Incompetent venous valves will have decreased what?

Answer 22

1. venous return
2. cardiac output

Question 23

Veins at rest (post contraction) act as what?

Answer 23

reservoirs for blood collection, with competent valves, maintain unidirectional movement of blood.

Question 24

What is referred to as the “venous heart”

Answer 24

Calf muscles

Question 25

During inspiration the diaphragm does what?

Answer 25

Descends

Question 26

During inspiration there is a decrease in what?

Answer 26

intrathoracic pressure (in the arms, head and neck). ***** Blood loves to go the way of less pressure****

Question 27

During inspiration there is an increase in what?

Answer 27

intra-abdominal pressure

Question 28

During inspiration, blood increases where?

Answer 28

in the arms, head, and neck veins.

Question 29

During expiration, there is an increase where?

Answer 29

in the intra-abdominal pressure

Question 30

During expiration, there is a decrease in what?

Answer 30

intrathoracic pressure

Question 31

During expiration, blood flow increases where?

Answer 31

in the lower extremity

Question 32

Portal vein flow has what 2 qualities?

Answer 32

1. minimially phasic 2. almost no variation with respiration

Question 33

What does a valsalva maneuver cause?

Answer 33

1. increased intrathoracic pressure 2. increased intra-abdominal pressure

Question 34

During a valsalva maneuver what is halted?

Answer 34

Venous return is halted.

Question 34

What is normal venous flow called?

Answer 34

spontaneous

Question 35

What is flow with alternating respirations?

Answer 35

Phasic flow

Question 36

Visible flow with hand compression is what?

Answer 36

augmentable

Question 37

Vessels close to the heart are what?

Answer 37

1. Pulsatile 2. bidirectional