LESSON 18 - venous return and the pulmonary circulation

Question 1

describe venous circulation :

Answer 1

a conduit return blood to the right side of the heart from the periphery

Question 2

describe the type of blood veins circulate :

Answer 2

veins return oxygenated blood to the heart but deoxygenated blood in rest of the body

Question 3

how many reservoirs for blood volume ?

Answer 3

5

Question 4

what are the 5 reservoirs for blood volume ?

Answer 4

• pulmonary
• veins
• heart
• arteries
• arterioles, capillaries

Question 5

what % of “reservoir” for blood volume is in the pulmonary ?

Answer 5

9%

Question 6

what % of “reservoir” for blood volume is in the veins ?

Answer 6

64%

Question 7

what % of “reservoir” for blood volume is in the arterioles & capillaries ?

Answer 7

7%

Question 8

what % of “reservoir” for blood volume is in the arteries ?

Answer 8

13%

Question 9

what % of “reservoir” for blood volume is in the heart ?

Answer 9

7%

Question 10

what is venous return (VR) ?

Answer 10

volume of blood that returns from the veins to the ratio each minute

Question 11

FILL IN THE BLANK

“venous return = rate of blood return from the ____ to the _____ “

Answer 11

veins to the atrium

Question 12

describe the venous return and cardiac output closed loop :

Answer 12

right ventricle … pulmonary … left ventricle … systemic …

Question 13

where within the closed loop do we see VR (venous return) ?

Answer 13

systemic to right ventricle

Question 14

where within the closed loop do we see CO (cardiac output) ?

Answer 14

right ventricle to pulmonary and left ventricle to systemic

Question 15

FILL IN THE BLANK

venous return = _________ = _________

Answer 15

right ventricle output = left ventricle output

Question 16

TRUE OR FALSE

all pumps have to be operated at the same speed

Answer 16

TRUE

Question 17

why must all pumps have to be operated at the same speed ?

Answer 17

to sustain that high level of cardiac output

Question 18

during exercise, an increase in venous return = ?

Answer 18

increase right ventricle and left ventricle filling

Question 19

how does venous return increase ?

Answer 19

during exercise (think of cardiac output)

Question 20

what is the formula for venous return (VR) ?

Answer 20

VR = ΔP / TVR

Question 21

what is TVR ?

Answer 21

resistance in the large veins and vena cave

Question 22

what is ΔP ?

Answer 22

pressure differential

Question 23

what is P venous (peripheral venous pressure) ?

Answer 23

pressure in the peripheral veins draining tissues

Question 24

which part of the venous return system is the highest point of pressure ?

Answer 24

the beginning of the system

Question 25

which parts of the circulatory system are a high pressure system and high resistance ?

Answer 25

- left ventricle -arteries - arterioles

Question 26

which parts of the circulatory system are a low pressure system and low resistance ?

Answer 26

- venules - veins

Question 27

between arteries and veins which have more smoother muscles ?

Answer 27

arteries

Question 28

within the circulatory system which are the exchange vessels ?

Answer 28

capillaries

Question 29

do we see low or high resistance in the venous circulation ?

Answer 29

low resistance

Question 30

describe the anatomy of veins :

Answer 30

- thinner walls - lack of smooth muscle - lack of sympathetic tone - more compliant

Question 31

describe the anatomy of arteries :

Answer 31

- thicker walls - lots of smooth muscle - more elasticity - easier to return to original state

Question 32

between veins and arteries which are more compliant ?

Answer 32

veins

Question 33

what does compliant mean ?

Answer 33

the ability of a blood vessel to adjust the blood pressure and increase the volume of blood that it can hold

Question 34

between veins and arteries which are more likely to blow open ?

Answer 34

venis

Question 35

between veins and arteries which have a higher resistance ?

Answer 35

arteries

Question 36

does venous return have any effect on stroke volume ?

Answer 36

no

Question 37

why do we see increasing preload ?

Answer 37

to facilitate the rise in venous return

Question 38

what is preload ?

Answer 38

the volume of blood received by the heart during (EDV)

Question 39

what does an increase in venous return mean for preload ?

Answer 39

increase in preload

Question 40

what is after load ?

Answer 40

how much blood is left in the left ventricle

Question 41

TRUE OR FALSE "the preload is the highest amount getting ready for contraction"

Answer 41

TRUE

Question 42

what are the effects of posture on venous pressure ?

Answer 42

when standing from supine, gravitational forced "pull" venous blood to the lower limbs

Question 43

FILL IN THE BLANK "due to the high compliance of veins around ____ mL of blood can redistribute to peripheral veins"

Answer 43

500mL

Question 44

"ever felt light headed when standing" is an example of what topic ?

Answer 44

effect of posture on venous pressure

Question 45

what is adema ?

Answer 45

buildup in blood volume

Question 46

does gravity pull blood volume up or down ?

Answer 46

down (ex. survivor challenge)

Question 47

if you're standing up for too long and feel light headed, what do we do to get rid of that gravitational force and to make the blood flow better ?

Answer 47

laying down

Question 48

is an increase in venous return necessary to increase cardiac output ?

Answer 48

yes, an increase in venous return is necessary to increase cardiac output

Question 49

an increase in what three things leads to an increase in cardiac output

Answer 49

- venous return - EDV - stroke volume

Question 50

how do venous blood flow in one direction ?

Answer 50

valves (prevent back flow, help continuously bring blood, etc)

Question 51

where do veins in the systemic system direct blood ?

Answer 51

direct blood to right atrium

Question 52

describe the valves in veins :

Answer 52

- thin - membranous flap-like valves - spaced at short intervals within veins

Question 53

what is the purpose of having valves ?

Answer 53

permit one way blood flow back to heart

Question 54

describe the pressure of blood in the large veins :

Answer 54

pressure of blood in the large veins is very low (difficult to return blood to heart)

Question 55

what are vessels within nucleus well tethered to ?

Answer 55

surrounding tissues (transmission of forces)

Question 56

when in the upright posture, gravity oppose what type of flow of blood and from where ?

Answer 56

gravity opposes the upward flow of blood from the lower body

Question 57

what are required to help increase venous return (veins/valves) ?

Answer 57

active mechanisms

Question 58

describe a skeletal muscle pump :

Answer 58

the mechanism whereby skeletal muscles aid the return of blood to the heart by compressing embedded veins

Question 59

what happens during exercise if there were no muscle pump ?

Answer 59

high flow of blood through muscle would lead to pooling in compliant vasculature

Question 60

what do muscle pumps prevent ?

Answer 60

pooling by maintaining a low volume of blood volume within muscle veins and displacing it back to heart

Question 61

what does tethering cause with skeletal muscle pump ?

Answer 61

causes negative venous pressure which "sucks" blood through muscle above what could be provided by left ventricle force alone

Question 62

describe veins during muscle contraction :

Answer 62

- muscles shorten - muscle pushes veins (massage like) - helps blood flow

Question 63

describe veins during muscle relaxation :

Answer 63

- muscles are not being pushed - generates forward pressure that shoots blood upwards towards the heart muscle lengthening

Question 64

what is the respiratory muscle pump ?

Answer 64

consists of abdominal and thoracic structures that are important in the expansion and contraction of the lungs

Question 65

what does decent of diaphragm during inspiration do to intra-abdominal pressure and pressure gradient between the thorax and abdomen (causing translation of blood centrally)

Answer 65

increase intra-abdominal pressure and increase in pressure gradient between thorax and abdomen

Question 66

during inspiration how does the diaphragm move ?

Answer 66

moves down

Question 67

during expiration how does the diaphragm move ?

Answer 67

moves up

Question 68

when does inspiration decrease intrathoratic pressure and increase pressure gradient ?

Answer 68

between the RA and system venous circuit (outside thoracic cavity)

Question 69

when the thoracic cavity decreases what does it mean for blood ?

Answer 69

increase in blood

Question 70

what happens to thoracic pressure of abdomen and thoracic cavity when you push diaphragm down ?

Answer 70

increase thoracic pressure of abdomen and thoracic cavity

Question 71

what is driving pressure ?

Answer 71

the difference between plateau pressure and positive end-expiratory pressure

Question 72

TRUE OR FALSE ? the right and left heart both circulate the same volume of blood at the same frequency

Answer 72

TRUE

Question 73

@ rest what is the L/min ?

Answer 73

5

Question 74

with low resistance circulation; pressure generated by RV is much less or much more than the left ?

Answer 74

much less

Question 75

@ severe exercise what is the L/min ?

Answer 75

20+

Question 76

describe the relationship of the Q LV vs Q RV on a graph :

Answer 76

- always the exact same - growing exponentially together

Question 77

describe the relationship of systemic arterial vs pulmonary arterial pressure on a graph :

Answer 77

significantly more pressure is generated on the L side (systemic) over the R side (pulmonary)

Question 78

describe the relationship of systemic peripheral vs pulmonary vascular resistance on a graph :

Answer 78

systemic starts super high and eventually falls way down while pulmonary maintains pretty low down

Question 79

what does greater aerobic fitness mean for resistance ?

Answer 79

less resistance in the pulmonary vasculature