Chapter 23 Venous Hemodynamics

Front 1

How much of total blood volume resides in the extrapulmonary venous system?

Back 1

Approximately 2/3. The venous system serves as a blood reservoir

Front 2

An effective venous return requires?

Back 2

Central Pump

Pressure Gradient

Peripheral Venous Pump

Competent Venous Valves

Front 3

What are the two types of pressure in the venous system? $$

Back 3

Dynamic Pressure

Hydrostatic Pressure

Front 4

Dynamic Pressure$$

Back 4

Occurs from cardiac contraction but most is lost through arterial circulation

Front 5

Hydrostatic pressure$$$

Back 5

The weight of the column of blood from the heart to any given spot on the body

Front 6

Hydrostatic pressure above the right atrium?

How about standing at the ankle? $$$

Back 6

Would be -50mmHg. But veins collapse at 0mmHg. So that is the lowest

Approx 100mmHg

Front 7

Normal venous flow pattern is$$

Back 7

Spontaneous with respiratory phasicity

Front 8

What happens during inspiration?$$$

Back 8

Lowers diaphragm

Intra abdominal pressure increases

Intra thoracic pressure decreases

Venous return from lower extremities decreases

Venous return from upper extremities increases

Front 9

What happens during expiration? $$$

Back 9

Raises diaphragm

Intra abdominal pressure decreases

Intra thoracic pressure increases

Venous return from lower extremities increases

Venous return from upper extremities decreases

Front 10

What does the valsalva maneuver do?

Back 10

It increases the thoracic and abdominal pressure. Stopping all venous flow.

Can be used as a proximal augmentation maneuver for evaluation of valve function

Front 11

What is used to overcome hydrostatic pressure?

Back 11

The peripheral muscular pumps overcome the hydrostatic pressure.

Front 12

What happens without the activation of the muscle pumps?

Back 12

Venous hypertension will result as blood is unable to return to the heart

Front 13

An ineffective calf muscle pump occurs when. . .

Back 13

Blood flow does not flow in the right direction. Example. Poor working valves resulting with backwards flow into the superficial system instead of the deep

Front 14

When calf muscles relax. . .$$$

Back 14

Blood is drawn from superficial to deep veins through the perforators

Front 15

Cardiac output equals venous return therefore the volume of blood carried by the arteries and veins is the

Back 15

Same. But venous stores more blood.

Front 16

Cardiac output equals venous return therefore the volume of blood carried by the arteries is the . . .

Back 16

Same

Front 17

Veins have the properties of high compliance and high capacitance, allowing the system to serve as a . . .$$$

Back 17

Reservoir for blood volume, primary in the lower extremities

Front 18

Compliance $$$@

Back 18

The ability to accommodate a large change in volume with small change in pressure

Front 19

Capacitance$$@

Back 19

Ability to accommodate a large change in volume in a short period of time

Front 20

Transmural pressure

Back 20

Relative intravascular to extravascular pressure difference

Front 21

What happened with low transmural pressure? $$

Back 21

Low, collapse.

Front 22

Transmural pressure

Back 22

Front 23

Venous resistance relationship to transmural pressure

Back 23

Indirect

High transmural pressure = low resistance

Low transmural pressure = high resistance