Venous Hemodynamics

Question 1

venous system serves as a ___ for blood

Answer 1

reservoir

Question 2

~ ⅔ of total blood volume resides in the ____ venous system

Answer 2

extrapulmonary

Question 3

effective venous return requires (4)

Answer 3

1. central pump
2. pressure gradient
3. peripheral venous pump
4. competent venous valves

Question 4

two main types of pressure in the venous system

Answer 4

dynamic pressure
hydrostatic pressure

Question 5

dynamic pressure generates from ___

Answer 5

cardiac contraction

Question 6

most of dynamic pressure is dissipated in the ___, remaining energy released in the ____

Answer 6

arterial circulation
released in the venous system

Question 7

dynamic pressure when supine

1. ____mmHg in the leg
2. ____mmHg at the right atrium
3. due to low venous pressure, ____ influences venous return

Answer 7

1. 8 mmHg in the leg
2. 0 mmHg at the right atrium
3. due to low venous pressure, respiratory motion influences venous return

Question 8

hydrostatic pressure is the ___ of the column of blood from the heart to any given spot on the body

Answer 8

weight

Question 9

hydrostatic pressure can be determined by considering ___ and the ___

Answer 9

blood density
acceleration of gravity

Question 10

hydrostatic pressure = pgh

p -
g -
h -

Answer 10

p - specific gravity of blood
g - acceleration of gravity
h - height (distance from the heart)

Question 11

the venous system is a ___ pressure system

Answer 11

low

Question 12

inspiration

___ the diaphragm
___ intrathoracic pressure
___ venous return from the lower extremities
___ venous return from the upper extremities

Answer 12

lowers the diaphragm
decreases intrathoracic pressure
decreased venous return from the lower extremities
increased venous return from the upper extremities

Question 13

expiration

___ the diaphragm
___ intrathoracic pressure
___ venous return from the lower extremities
___ venous return from the upper extremities

Answer 13

raises the diaphragm
increases intrathoracic pressure
increased venous return from the lower extremities
decreased venous return from the upper extremities

Question 14

valsalva maneuver increases (2)

Answer 14

intrathoracic and intra-abdominal pressure
ALL venous flow stops

Question 15

valsalva maneuver is used as a proximal augmentation maneuver for evaluation of ___

Answer 15

valve function

Question 16

peripheral pumps propel blood upward to overcome the ___

Answer 16

hydrostatic pressure

Question 17

the most important peripheral pump is the ___ and it is activated with ___

Answer 17

calf muscle
activated with walking

Question 18

without the activation of muscle pumps, ___ is inadequate to return blood from the dependent limb to the heart and ___ results

Answer 18

dynamic pressure
venous hypertension results

Question 19

calf muscle contraction

1. squeeze the ___
2. blood flows ___ the heart in both superficial and deep systems
3. ___ valve are closed
4. valves prevent ___

Answer 19

1. squeeze the deep veins
2. blood flows towards the heart in both superficial and deep systems
3. perforator valve are closed
4. valves prevent venous backflow

Question 20

calf muscle relaxed

1. ___ vein decompresses and expands
2. blood is drawn from the superficial and deep veins through the ____
3. blood is sucked from ___ and ___ through the calf
4. ___ valves are closed, reducing local venous pressure

Answer 20

1. deep vein decompresses and expands
2. blood is drawn from the superficial and deep veins through the perforators
3. blood is sucked from capillaries and venules through the calf
4. upstream valves are closed, reducing local venous pressure

Question 21

ineffective calf muscle pump or outflow obstruction

1. blood flows ___ from deep to superficial veins through incompetent perforators
2. blood flows distally towards the ___
3. ___ circular flow of blood
4. results in ___ and ___

Answer 21

1. blood flows outward from deep to superficial veins through incompetent perforators
2. blood flows distally towards the foot
3. inefficient circular flow of blood
4. results in venous pooling and ambulatory venous hypertension

Question 22

venous valves are one way valves the generally direct flow ___ and ___

Answer 22

inward and upward

Question 23

venous valves are susceptible to (3)

Answer 23

disease
damage
incompetence

Question 24

incompetent venous valves decrease ejection of blood, allow __ to occur

Answer 24

reflux

Question 25

ineffective muscle pump results in increased ___ and ___ leading to ambulatory venous hypertension

Answer 25

venous volume and pressure

Question 26

veins are very ___ and change shape with demand

Answer 26

elastic

Question 27

veins have the property of high ___ and high ___

Answer 27

compliance and capacitance

Question 28

compliance or capacitance ___ is the ability to accommodate a large change in volume with a small change in pressure

Answer 28

compliance **pressure

Question 29

compliance or capacitance ___ is the ability to accommodate a large change in volume in a short period of time

Answer 29

capacitance **time

Question 30

what is transmural pressure?

Answer 30

relative pressure difference from within the vessel to out (intravascular pressure vs tissue pressure)

Question 31

transmural pressure is always references from ___

Answer 31

inside the vessel

Question 32

when tissue pressure exceeds the intravascular pressure, the transmural pressure is considered ___ and the vessel ___

Answer 32

considered low vessel collapses

Question 33

high venous pressure ___ tissue pressure ___ transmural pressure ___ vein ___ resistance

Answer 33

low tissue pressure high transmural pressure distended vein lower resistance

Question 34

low venous pressure ___ tissue pressure ___ transmural pressure ___ vein ___ resistance

Answer 34

high tissue pressure low transmural pressure collapsed vein high resistance

Question 35

veins offer ___ to flow similar to the arteries but can vary significantly due to ___

Answer 35

offer resistance vary due to elasticity

Question 36

a distended vein offers ___ resistance than a flattened vein

Answer 36

lower resistance