Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIOL 2010 > Cardiovascular System: Blood Flow & Pressure > Flashcards

Cardiovascular System: Blood Flow & Pressure Flashcards

1
Q

what tissue(s) are present in artery walls; purpose?

A
  • elastic and fibrous
  • provides stiffness and flexibility
  • act as pressure reservoirs allowing for smooth blood flow
  • elastin can act like springs (elastic force stored and passive recoil)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

how can arteries act like pressure reservoirs

A
  • arteries have low compliance
  • large ↑ in pressure won’t lead to large degree of expansion of vessel wall
  • ensures smooth flow of blood even when heart is in diastole
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

how can veins act like volume/blood reservoirs

A
  • veins have high compliance
  • large ↑ in pressure leads to large ↑ in vessel wall expansion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

define compliance

A

measure of how pressure of a vessel will change with a change in volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

how are systolic and diastolic blood pressure different

A

systolic = maximum; diastolic = minimum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what causes systolic blood pressure

A

ejection of blood into aorta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what causes diastolic blood pressure

A

elastic recoil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what does diastolic blood pressure refer to

A

slow decline in pressure to minimum right before the next systole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

define MAP

A
  • mean arterial pressure
  • average pressure in arteries that occurs during one cardiac cycle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

how do we measure blood pressure

A
  • arterial pressure estimated using brachial artery
  • systolic (SP)/diastolic (DP)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what does korokoff sound refer to

A

“vibrations” made from pressure in artery when checking blood pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how can we determine pulse pressure (PP)

A

systolic (SP) - diastolic (DP)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is the importance of pulse pressure

A

high pulse pressure (especially amongst older individuals) can indicate hardening of the arteries (thickened and rigid from plaque) leading to a decrease in stretch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how can we find MAP

A

[SP + (2*DP)] / 3

MAP is weighted mean (single cardiac cycle is at maximum for short amt of time whereas minimum is at twice the amt of time)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

describe arterioles

A
  • smaller than arteries
  • aka resistance vessels
  • connectors of arteries to capillaries or metarterioles
  • have rings of smooth muscle that regulate radius and resistance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how are arterioles and resistance related

A
  • arterioles are best site where resistance to flow can be regulated
  • > 60% of total peripheral resistance attributed to arterioles
  • largest pressure drop in vasculature occurs along here since they have greatest resistance to blood flow
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

define TPR

A
  • total peripheral resistance
  • combined resistances of all blood vessels with the circuit in the systemic system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

how is resistance in arterioles regulated by

A

contraction/relaxation of circular smooth muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what are the main functions of arterioles

A
  • control blood flow to individual capillary beds
  • regulate MAP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how can arteriole radius change

A
  • dependent on contraction state of smooth muscle in arteriole wall
  • arteriolar tone
  • vasoconstriction
  • vasodilation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

how does vasodilation affect arteriole radius

A

↑ radius due to ↓ contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

how does vasoconstriction affect arteriole radius

A

↓ radius due to ↑ contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

define arteriolar tone

A

when contraction level (radius) is independent of extrinsic influences

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

describe hyperemia

A

higher than normal blood flow rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

list the ways that intrinsic control of arteriole smooth muscle happens

A
  • changes in metabolic activity
  • changes in blood flow
  • stretch of smooth muscles in arterioles
  • local chemical messengers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

describe how changes in metabolic activity affect arteriole smooth muscle

A
  • vasodilation generally happens with ↑ metabolic activity
  • vasoconstriction generally happens with ↓ metabolic activity
  • smooth muscle sensitive to ECF conditions and respond to CO2, K+, H+ concentrations
  • EX active hyperemia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

how does active hyperemia happen

A

changes from O2 and CO2 in response to metabolic activity change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

how does reactive hyperemia happen

A

changes from O2 and CO2 in response to blood flow change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

arterial blood pressure refers to pressure in

A

aorta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

draw out the flow of smooth muscle stretch in arterioles

A

Increase in perfusion pressure → arteriolar smooth
muscles contract → vasoconstriction → increased
resistance → decreased flow

31
Q

describe myogenic response of smooth muscle in arterioles

A
  • reflex response of afferent arterioles to changes in blood pressure
  • some tissues have stretch-sensitive fibres that stretch when BP in arterioles ↑
32
Q

which local chemical messengers are important for intrinsic control of arteriole smooth muscle and why

A
  • nitric oxide and prostacyclin (vasodilation)
  • endothelin-I (vasoconstriction)
33
Q

what are some extrinsic factors of arteriole smooth muscle control

A
  • sympathetic nerves
  • epinephrine
  • vasopressin (ADH)
  • angiotensin II
34
Q

how do sympathetic nerves affect arteriole radius, and how does that affect MAP

A

vasoconstriction; ↑ MAP

35
Q

how does epinephrine affect arteriole radius, and how does that affect MAP

A
  • depends on the receptor
  • α adrenergic: vasoconstriction
  • β2 adrenergic: vasodilation
  • ↑ MAP bc α is dominant
36
Q

how does vasopressin affect arteriole radius, and how does that affect MAP

A

vasoconstriction; ↑ MAP

37
Q

how does angiotensin II affect arteriole radius, and how does that affect MAP

A

vasoconstriction; ↑ MAP

38
Q

how does blood flow regulate in microcirculation

A

through arterioles, metarterioles, precapillary sphincters

39
Q

define microcirculation

A
  • simplest way to regulate exchange of material across capillary walls
  • arterioles to precap sphincter to metarterioles/capillaries to venules
40
Q

describe precapillary sphincter

A

rings of smooth muscle before capillary bed

41
Q

what are the transport mechanisms of capillary wall material exchange

A
  • simple diffusion
  • mediated transport
  • transcytosis
42
Q

describe metarterioles

A
  • intermediate structure between arterioles and capillaries
  • rings of smooth muscle
  • acts like shunts from arterioles to venules
43
Q

why are precapillary sphincters important

A
  • they regulate flow thru capillary bed
  • contraction leads to capillary contraction leading to ↓ in flow thru capillary bed
44
Q

when there is high or low resistance to flow in metarterioles, where does blood flow occur

A

inc in capillary beds; dec in capillary beds

pulsing manner between metarterioles and capillary beds based on conditions

45
Q

what are the transport mechanisms of capillary wall material exchange

A
  • simple diffusion thru membrane cells and pores
  • mediated transport
  • transcytosis
46
Q

describe bulk flow across capillary walls

A
  • capillary walls are water- and small solute permeable
  • fluids are able to move from blood to interstitial fluid (vice versa)
47
Q

what is filtration

A

blood to interstitial fluid material transport

48
Q

what is absorption

A

interstitial fluid to blood material transport

49
Q

define edema

A

shift of fluid from plasma to interstitial fluid (ie swelling)

50
Q

define starling forces; what are some examples

A
  • forces that drive movement of fluid in/out of cell
  • capillary hydrostatic pressure (P CAP)
  • interstitial fluid hydrostatic pressure (P IF)
  • capillary osmotic pressure (π CAP)
  • interstitial fluid osmotic pressure (π IF)
51
Q

draw out material exchange b/w plasma and interstitial fluid

A

…

52
Q

define capillary hydrostatic pressure (P CAP) and its direction of force

A

hydrostatic pressure exerted by presence of fluid inside the capillary; filtration

53
Q

define interstitial fluid hydrostatic pressure (P IF) and its direction of force

A

hydrostatic pressure exerted by presence of fluid outside the capillary; absorption

54
Q

define capillary osmotic pressure (π CAP) and its direction of force

A

osmotic force due to presence of proteins in plasma; absorption

55
Q

define capillary osmotic pressure (π IF) and its direction of force

A

osmotic force due to presence of proteins in interstitial fluid; filtration

56
Q

define net filtration pressure (NFP) and its direction of force

A
  • difference bw forces for filtration and absorption (eqn = filtration pressure - absorption pressure);

Answer is + then filtration occurs at arteriole end, - then absorption occurs at venule ends

57
Q

why is P cap displayed as a range in values

A
  • pressure varies across capillary beds
  • initial value represents venous ends
  • end value represents arteriole ends
58
Q

list factors that influence venous pressure and return

A
  • skeletal muscle pump
  • respiratory pump (inspiration/exhalation)
  • blood volume
  • venomotor tone
59
Q

how do skeletal muscle pumps affect venous pressure and return

A
  • skeletal muscles contract (squeezing of veins, blood flows to heart) and relax (blood flows to veins)
  • there are one-way valves in peripheral veins, whereas none in central veins
60
Q

describe inspiration

A
  • diaphragm moves down which ↓ pressure in thoracic cavity and ↑ pressure in abdominal cavity
  • gradient is made to favour blood movement in TC
  • blood moves from abdominal veins to central veins in TC which causes blood to flow towards the heart
61
Q

describe exhalation

A

reversal of pressure and creates pressure gradient that would favour bkwd movement of blood (but doesn’t happen)

62
Q

why does bkwd movement of blood from exhalation not happen

A

due to the one-way valves

63
Q

what is the relationship b/w blood volume and venous pressure

A

directly proportional (inc leads to inc, dec leads to dec)

64
Q

what is venomotor tone

A

smooth muscle tension in veins

65
Q

what are the effects of increased venomotor control

A
  • constriction of veins ↑ venous pressure which makes blood move towards heart
  • ↑ wall tension reduces compliance which ↑ venous pressure and ↑ stroke volume
66
Q

define stroke volume

A

volume of blood ejected from each ventricle during a single heartbeat

67
Q

describe the flow of oxygenated blood in the heart

A
  • arteries carry oxygenated blood to arterioles then capillary beds
  • gas exchange occurs
  • blood flows to venules then veins then vena cava then back to heart to be oxygenated again
68
Q

what is the significance of large arteries

A

have little resistance to flow

69
Q

how is it that the diameter and thickness of the veins is so low

A

the pressure of blood flowing thru it is much lower, which allows it to withstand the flow

70
Q

what is the importance of valves in veins

A

prevent back flow since it’s going upward

71
Q

draw out the generic vasculature of blood flow to and away from heart

A

…

72
Q

what is diastole

A

small period of time when the heart is not pumping

73
Q

what is the importance of elastin fibres in vessel walls

A
  • act like a spring
  • during systole, pressure of left ventricle is greater than pressure in arteries
  • this causes blood to flow into arteries which leads to a stretch to compensate for increased volume
  • in diastole, valves close and allow walls to passively recoil inwards to help push blood along (result of stored elastic force)
74
Q

define elasticity

A

resistance to change

BIOL 2010 (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions