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PHYSL 212 > Unit 6 - Cardiovascular Physiology > Flashcards

Unit 6 - Cardiovascular Physiology Flashcards

1
Q

why do we have a cardiovascular system?

A
  • diffusion is not adequate to exchange nutrients/ waste to cells because the distance is too large
  • circulation provides a steep concentration gradient in close proximity to every cell allowing for RAPID exchange of materials
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2
Q

what are hemodynamics?

A

looks at the laws that govern blood flow

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3
Q

what is the equation for flow?

A

F = (delta)P / R
where:
- F = flow
- (delta)P = pressure difference between two fixed points
- R = resistance to flow

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4
Q

true or false: to have flow, pressure must be greater than resistance

A

true

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5
Q

pressure exerted by a fluid

A

hydrostatic pressure

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6
Q

what happens if there is no pressure difference?

A

there will not be any flow. it is the pressure difference, not the absolute pressure, that creates flow

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7
Q

what creates blood flow?

A

a pressure gradient

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8
Q

cardiovascular pressure is created from:

A

contraction of heart chambers and pressure of blood on walls of blood vessels and heart chambers

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9
Q

friction between molecules of a flowing fluid

A

viscosity

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10
Q

determines the amount of contact between moving blood and stationary wall of vessel

A

length and diameter

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11
Q

in small blood vessels, there is less blood in the _______ and on the ________

A

center, vessel wall

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12
Q

in large blood vessels, there is more blood in the ______, which creates ______

A

center, less friction

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13
Q

what is poiseuilles equation?

A

R = (8nl) / (pi*r^4)
where:
- R = resistance to blood flow
- n = viscosity of blood
- l = length of vessel
- r = radius of vessel

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14
Q

true or false: poisseuilles equation applies to all types of blood flow

A

false, it only applies to laminar (smooth) blood flow

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15
Q

in fluid dynamics, __________ is characterized by fluid particles following smooth paths in layers, with each layer moving slowly

A

laminar flow

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16
Q

at forks in the blood vessels, is flow more laminar or turnbulent?

A

turbulent

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17
Q

what are the four main functions of the cardiovascular system?

A

1) delivery of oxygen and nutrients and removal of waste products
2) fast chemical signalling to cells by circulating hormones and neurotransmitters
3) thermoregulation
4) mediation of inflammatory and host defense responses against invading microorganisms

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18
Q

what are the three main components of the cardiovascular system?

A

1) the heart
2) blood vessels
3) blood

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19
Q

small branching vessels with high resistance

A

arterioles

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20
Q

transport blood between small arteries and venules; exchange of materials

A

capillaries

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21
Q

carries blood with a mostly high oxygen content away from the heart

A

arteries

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22
Q

carries blood with mostly low oxygen content towards the heart

A

veins

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23
Q

what does it mean to have a closed circulatory system?

A

blood never leaves the vessels/ chambers of the heart

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24
Q

how many chambers are in the heart?

A

four. two atria, two ventricles

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25
Q
  • thin-walled
  • low pressure chambers
  • receive blood returning to the heart
A

atria

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26
Q

responsible for the forward propulsion of blood

A

ventricles

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27
Q

the two sides of the heart are divided by the:

A

septa

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28
Q

separates the left and right atria

A

interatrial septum

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29
Q

separates the left and right ventricles

A

interventricular septum

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30
Q

the circulatory system consists of two circuits. what are they?

A
  • pulmonary circulation
  • systemic circulation
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31
Q
  • blood to and from the gas exchange surfaces of the lungs
  • blood entering lungs = poorly oxygenated blood
  • oxygen diffuses from lung tissue to blood
  • blood leaving lungs= oxygenated blood
    these are all chracteristics of:
A

pulmonary circulation

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32
Q
  • blood to an from the rest of the body
  • blood entering tissues = oxygenated blood
  • oxygen diffuses from blood to body tissues
  • blood leaving tissues = poorly oxygenated bloos
A
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33
Q
  • blood to and from the rest of the body
  • blood entering tissues = oxygenated blood
  • oxygen diffuses from blood to body tissues
  • blood leaving tissues = poorly oxygenated blood
    These are all characteristics of:
A

Systemic circulation

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34
Q

Receives blood from pulmonary circulation and pumps to systemic circulation

A

Left heart

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35
Q

Receives blood from systemic circulation and pumps to pulmonary circulation

A

Right heart

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36
Q

Blood flows in a _____

A

Series/ sequence

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37
Q

Blood must pass through the pulmonary and systemic circuits in _________

A

Sequence

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38
Q

What is parallel flow within the systemic circuit?

A
  • each organ is supplied by a different artery
  • independently regulate flow to different organs
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39
Q

What is the exception to parallel flow?

A

The digestive system. Blood flows from the aorta to the digestive system and then to the liver (about 75% of the blood that the liver receives is from the digestive system).

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40
Q

At rest, the body pumps the entire blood volume in a loop every minute. How much blood is this?

A

5L/min

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41
Q

During strenuous exercise, the body pumps your entire blood volume around the circuits 3.5 times per minute. How much blood is this?

A

17.5L/min

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42
Q

Fibrous sac surrounding the heart and roots of great vessels

A

Pericardium

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43
Q

What are the four main functions of the pericardium?

A

1) holds the heart in place in the thoracic cavity
2) protection of the heart from mechanical trauma and infection
3) secretes pericardial fluid to reduce friction
4) limits overfilling of the chambers, prevents sudden distension

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44
Q

What are the three layers to the pericardial structure?

A

1) fibrous pericardium
2) parietal pericardium
3) visceral epicardium

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45
Q

How much fluid does the pericardial cavity hold?

A

15-20mL

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46
Q

Pericardial fluid decreases _______

A

Friction

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47
Q

The “organ” attached to the heart

A

The visceral layer

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48
Q

Inflammation of the pericardium

A

Pericarditis

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49
Q

Compression of heart chambers due to excessive accumulation of pericardial fluid

A

Cardiac tamponade

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50
Q

True or false: the left ventricular wall is thicker than the right ventricle

A

True

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51
Q

covers the outer surface of heart

A

epicardium

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52
Q

the muscular wall, contains myocytes, blood vessels, nerves

A

myocardium

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53
Q

endothelium covering inner surfaces of the heart and heart valves

A

endocardium

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54
Q

cardiac muscle cells

A

myocyte

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55
Q
  • branched and joined longitudinally
  • striated
  • one nucleus per cell
  • many mitochondria
    these are characteristics of:
A

myocytes

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56
Q

interdigitated region of attachment (desmosomes and gap junctions)

A

intercalculated disk

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57
Q

anchor calls together in tissues subject to considerable stretching, mechanically couples cells

A

desmosomes

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58
Q

transmembrane channels linking adjacent cells, used for communication between cells

A

gap junctions

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59
Q

allows the passage of small molecules and ions, spreading action potentials across the atria/ ventricles

A

gap junctions

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60
Q

consists of interlacing bundles of muscle fibers arranged spirally around the circumference of the heart?

A

myocardium

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61
Q

why do the myocardium muscle fibers have a spiral arrangement?

A

when the cardiac muscles contract, a wringing effect occurs, which efficiently pushes heart up to exit the heart

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62
Q

thin flaps of flexible, endothelium-covered fibrous tissue attached at the base to rings

A

valves

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63
Q

made of cartilage and are the site of attachment for the heart valves

A

valve rings

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64
Q

how do the valves function to provide unidirectional flow of blood through the heart?

A
  • forward pressure gradient opens the one-way valve
  • backward gradient closes the one-way valve but it cannot open in the opposite direction
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65
Q
  • between the atria and ventricles
  • prevent backflow of blood into the atria when ventricles contract
    these are characteristics of the:
A

atrioventricular valves

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66
Q

what is the tricuspid valve?

A

the right atrioventricular valve that is made up of three leaflets (or cusps)

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67
Q

what is the bicuspid/ mitral valve?

A

the left atriventricular valve that is made of of two leaflets

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68
Q

what components make up the AV valve apparatus?

A

cusps, chordae tendineae and papillary muscles

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69
Q

tendinous type tissue which extends from the edges of each leaflet of the AV valves to the papillary muscle

A

chordae tendineae

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70
Q

cone shaped muscles which cause the chordae tendineae to become taut when contracting

A

papillary muscles

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71
Q

what is the function of the AV valve apparatus?

A

prevents the AV valves from turning inside out during contraction of the ventricles

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72
Q

true or false: valves open and close due to contraction and relaxation of the papillary muscles

A

false: they open and close due to pressure gradients

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73
Q
  • located between the ventricles and arteries
  • prevent backflow of blood from the arteries into ventricles when the ventricles relax
A

arterial (semilunar) valves

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74
Q

how many cusps does each semilunar valve have?

A

three

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75
Q

where is the pulmonary valve located?

A

between the pulmonary trunk and the right ventricle

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76
Q

where is the aortic valve located?

A

between the aorta and the left ventricle

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77
Q

do the semilunar valves have chordae tendineae and papillary muscles?

A

no

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78
Q

movement of blood through the tissues of the heart

A

coronary circulation

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79
Q

originate at aortic sinuses at the base of the ascending aorta

A

coronary arteries

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80
Q

drain into the coronary sinus, which empties into the right atrium

A

coronary veins

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81
Q

where does the coronary sinues empty?

A

the right atrium

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82
Q

collection of veins joined together to form a large vessel that collects blood from the myocardium of the heart

A

coronary sinus

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83
Q

in coronary circulation, at what point does myocardial blood flow almost cease?

A

systole (contraction)

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84
Q

in coronary circulation, at what point does myocardial blood flow peak?

A

diastole (relaxation)

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85
Q

a condition where arteries supplying blood to the heart become hardened and narrow due to plaque in the arterial walls

A

atherosclerosis

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86
Q

a condition where blood flow to the heart muscle is reduced, causing chest pain or discomfort

A

angina

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87
Q

a condition where blood supply to the heart is completely blocked and the muscle dies

A

myocardial infarction (heart attack)

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88
Q
  • dense connective tissue between the valve rings
  • separates atria from ventricles
  • electrically inactive
  • provides support for the heart (point of attachment for valve leaflets)
    these are characteristics of the:
A

cardiac skeleton

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89
Q

myocytes communicate with one another, and this arrangement is called a:

A

syncytium

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90
Q

what is a syncytium?

A

a set of cells that act together

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91
Q

in a functional syncytium, if one cell is excited, the excitation spreads over:

A

both ventricles/ atria

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92
Q

how many syncytia systems are there?

A
  1. an atrial syncytium and a ventriculat syncytium
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93
Q

true or false: the cardiac sycytium has an all-or-none property

A

true

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94
Q

the heart is capable of generating its own ________ without nervous or hormonal stimulation

A

action potentials

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95
Q

what are the two types of myocytes?

A

contractile cells and conducting cells

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96
Q

myocytes which do the mechanical work of pumping, propel blood; do not initiate action potentials

A

contractile cells

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97
Q

myocytes which initiate and conduct the action potentials responsible for contraction of the contractile cells

A

conducting cells

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98
Q

what are the six key components of the conducting system?

A

1) sinoatrial (SA) node
2) internodal pathways
3) atrioventricular (AV) node
4) bundle of His (AV bundle)
5) bundle branches (left and right)
6) purkinjie fibers

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99
Q

the only electrical connection between the atria and ventricles

A

AV node and bundle of His

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100
Q

known as the cardiac pacemaker which initiates action potentials and sets the heart rate

A

sinoatrial (SA) node

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101
Q

passes stimuli to the contractile cells of both atria and to the AV node

A

internodal pathways

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102
Q

how long is the AV nodal delay?

A

100 msec

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103
Q

what is the purpose o the AV nodal delay?

A

ensures that the atria depolarize and contract before the ventricles, and gives the ventricles time to fill completely before they contract

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104
Q

where do the bundle branches travel along?

A

the interventricular septum

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105
Q
  • large number
  • diffuse distribution
  • fast conduction velocity
    these are all properties of the:
A

purkinjie fibers

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106
Q

the purkinjie fibers ensure that the right and left ventricles contract _______

A

simultaneously

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107
Q

what is the sequence of the conducting system?

A

SA node –> internodal pathway –> atrial myocardium –> AV node –> bundle of His –> right and left bundle branches –> purkinjie fibers –> ventricular myocardium

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108
Q

provides another electrical pathway where stimulus can pass backwards into the atria

A

the accessory pathway

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109
Q

irregular heart rate which doesn’t allow the chambers to fill with blood

A

arrhythmia

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110
Q

how many types of action potentials are in the cardiovascular system?

A

two

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111
Q

where does the fact action potential occur?

A

atrial myocardium, ventricular myocardium, bundle of His, bundle branches, purkinjie fibers, and internodal pathways

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112
Q

where does the slow action potential occur?

A

SA node, and AV node

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113
Q

phases of the cardiac action potential are associated with changes in permeability of the cell membrane mainly to what ions?

A

Na+, K+, and Ca2+

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114
Q

what is the function of the pacemaker potential?

A

allows the heart to generate its own action potential

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115
Q
  • slow depolarization to threshold
  • regular spontaneous generation of action potentials
    these are characteristics of:
A

the pacemaker potential

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116
Q

list the channels involved in the pacemaker potential

A
  • K+ channels: iK
  • F-type channels (funny): iNa
  • T-type channels (transient): iCa
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117
Q

what are the ion channels involves in SA node depolarization?

A

L-type channels (long lasting): iCa.

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118
Q

which is open longer: T-type or L-type channels?

A

L-type

119
Q

during the slow action potential, the depolarization phase is slow due to:

A

slow movement of Ca2+

120
Q

which rises to threshold quicker, the SA node or the AV node?

A

SA node

121
Q

during ventricular muscle cell action potential, the “notch” occurs due to:

A

transient opening of K+ channels (slight repolarization)

122
Q

during ventricular muscle cell action potential, the plateau occurs due to:

A

Ca2+ entering through L-type channels and slow oppening of K+ channels that will repolarize the cell

123
Q

during ventricular muscle cell action potential, repolarization occurs due to:

A

opening of K+ channels and closing of Ca2+ channels

124
Q

during ventricular muscle cell action potential, the stable resting phase occurs due to:

A

the Na+/K+ pump continuously pumping ions in and out of the cells

125
Q

during ventricular muscle cell action potential, depolarization occurs due to:

A

opening of fast voltage-gated Na+ channels at threshold

126
Q

what is responsible for AV nodal delay?

A
  • no fast voltage-gated Na+ channels in AV node
  • depolarization slow due to L-type Ca2+ channels
127
Q

what is an electrocardiogram (ECG)?

A

a graphical recording of elevtrical activity of the heart detected on the surface of the body

128
Q

voltage gradients in the heart may be as much as ____mV, this is translated to changes of up to ____mV at the skin surface

A

100mV, 1mV

129
Q

in an ECG recording, what does the P-wave represent?

A

the spread of depolarization across the atria

130
Q

in an ECG recording, what does the QRS complex represent?

A

spread of depolarization across ventricles

131
Q

in an ECG recording, what does the T-wave represent?

A

ventricular repolarization

132
Q

why doesn’t the SA node action potential show up on an ECG?

A

the signal isn’t strong enough to get to the surface of the skin

133
Q

why doesn’t atrial repolarization show op on an ECG?

A

it is too smal of an electrical event to be recorded

134
Q

in an ECG recording, what does the PR interval respresent?

A

atrial depolarization and physiological delay of the stimulus in the AV node

135
Q

in an ECG recording, what does the QR interval represent?

A

ventricular depolarization and repolarization

136
Q

in an ECG recording, what does the ST-segment represent?

A

isoelectric period of depolarized ventricles; end of QRS to beginning of T-wave

137
Q

in an ECG recording, what does it mean if every second P-wave is not followed by a QRS complex?

A

there is a partial AV node block

138
Q

in an ECG recording, what does it mean if there is no synchrony between atrial and ventricular electrical activities

A

there is complete AV node block

139
Q

the cell membrane of the muscle cell

A

sarcolemma

140
Q

stores calcium ions for contraction (acts like smooth ER)

A

sarcoplasmic reticulum

141
Q

invaginations of the sarcolemma; transmit depolarization of membrane into interior of muscle cell

A

T-tubules

142
Q

what are myofibrils made of?

A

contractile proteins

143
Q

what regulates the contraction of cardiac muscle?

A

calcium ions

144
Q

what is a calcium-dependent calcium release?

A

calcium ions bind to ryanodine receptors, releasing calcium from the sarcoplasmic reticulum

145
Q

contains binding sites for calcium and tropomyosin, and regulates access to myosin binding sites

A

troponin

146
Q

partially cover the myosin binding sites on actin at rest, preventing cross-bridges from making contact with actin

A

tropomyosin

147
Q

how is Ca2+ returned to the sarcoplasmic reticulum?

A

Ca2+ ATPase

148
Q

how does Ca2+ leave the cardiac muscle cell?

A

through an Na+/Ca2+ exchanger

149
Q

a period of time in which a new action potential cannot be initiated

A

refractory period

150
Q

how long does the absolucte refractory period in a cardiac muscle cell last?

A

~250 msec

151
Q

a pro-longed, smooth contraction; great for skeletal muscle, not good for cardiac muscle

A

tetanic contraction

152
Q

how is tetanus prevented?

A

the refractory period

153
Q

true or false: the AV node can act as a pacemaker if SA node becomes damaged

A

true

154
Q

true or false: long absolute refractory period in myocytes prevents summation of contraction

A

true

155
Q

true or false: if the fast Na+ current fails, the L-type Ca2+ current can cause depolarization

A

true

156
Q

true or false: IK1 keeps resting potential more negative so that more stimulus is needed to reach threshold, preventing spontaneous activity

A

true

157
Q

ventricular/atrial contraction and ejection

A

systole

158
Q

ventricular/atrial relaxation and blood filling

A

diastole

159
Q

why is diastole longer than systole?

A

because you have to ensure the chamber fills with blood

160
Q

all heart valves closed, blood volume in ventricles remains constant, pressures rise. muscle develops tension but cannot shorten.

A

isovolumetric contraction

161
Q

pressure in ventricles exceeds that in arteries, semilunar valves open and blood ejected into the artery. muscle fibers of ventricles shorten

A

ventricular ejection

162
Q

volume of blood ejected from each ventricle during systole

A

stroke volume

163
Q

how much blood is ejected in the stroke volume?

A

~70 - 75mL

164
Q

true or false: during ejection, the chambers of the heart are completely emptied of blood

A

false

165
Q

all heart vavles closed, blood volume remains constant, pressures drop

A

isovolumetric ventricular relaxation

166
Q

AV valves open, blood flows into ventricles from atria, ventricles receive blood passively.

A

ventricular filling

167
Q

atria contract at the end of ventricular filling in order to top up the blood volume in the ventricle

A

atrial kick

168
Q
A
169
Q

true or false: Wigger’s diagram represent the left side of the heart due to increased pressure

A

true

170
Q

_________ is the key to understanding blood flow patterns and opening/closing of valves

A

pressure

171
Q

blood flows from regions of _________ to regions of ________

A

higher pressure, lower pressure

172
Q

the amount of blood in each ventricle at the end of ventricular diastole

A

end-diastolic volume

173
Q

the amount of blood in each ventricle at the end of ventricular systole

A

end-systolic volume

174
Q

what is the equation for stroke volume?

A

SV = EDV - ESV

175
Q

during systole, which ventricle develops lower pressure?

A

the right ventricle

176
Q

what does the “lub” sound of the heart represent?

A

closure of the AV vlaves

177
Q

what does the “dub” sound of the heart represent?

A

closure of the semilunar valves

178
Q

what does it mean for the heart to “murmur”?

A

turbulent blood flow that makes a sound

179
Q

blood flows rapidly through a narrowed valve; leaflets do not open completely

A

stenosis

180
Q

blood flows backward through leaky valve; leaflets do not close completely

A

insufficiency

181
Q

the ability of a blood vessel to stretch

A

compliance

182
Q

what is the formula for compliance?

A

compliance = (change in volume) / (change in pressure)

183
Q

large arteries function as pressure reservoirs due to:

A

elastic recoil

184
Q

what does elastic recoil of arteries do?

A

pushes blood forward

185
Q

where does the sympathetic nervous system act in the heart?

A

atria, ventricles, SA node, AV node

186
Q

where does the parasympathetic nervous system act in the heart?

A

atria, SA node, AV node

187
Q

what does parasympathetic innervation do to the SA node?

A

decreases the rate of depolarization to threshold; decreasing heart rate

188
Q

what does parasympathetic innervation do to the AV node?

A

decreases conduction; increases AV nodal delay

189
Q

what does parasympathetic innervation do to the artial muscles?

A

decreases contractility

190
Q

what does parasympathetic innervation do to the ventricular muscles?

A

no effect

191
Q

what does sympathetic innervation do to the SA node?

A

increases the rate of depolarization to threshold; increases heart rate

192
Q

what does sympathetic innervation do to the AV node?

A

increases conduction; decreases AV nodal delay

193
Q

what does sympathetic innervation do to the atrial muscles?

A

increases contractility

194
Q

what does sympathetic innervation do to the ventricular muscles?

A

increases contractility

195
Q

the amount of blood pumped by each ventricle in one minute

A

cardiac output

196
Q

what is the equation for cardiac output?

A

cardic output (CO) = heart rate (HR) * stroke volume (SV)

197
Q

what are the two main factors that affect cardiac output?

A
  • altering the activity of the SA node
  • altering the contractility of the ventricular myocardium
198
Q

heart rate is increased by:

A

increasing sympathetic activity

199
Q

heart rate is decreased by:

A

parasympathetic activity

200
Q

sympathtic stimulation to the heart increases _____ and ____ channel permeability

A

L-type, T-type

201
Q

parasympathetic stimulation to the heart deacreases ______ channel permeability

A

F-type

202
Q

what are the three main factors that affect stroke volume?

A

1) end-diastolic volume (EDV)
2) contractility of ventricles
3) afterload

203
Q

the tension or load on the myocardium before it begins to contract. aka: the amount of filling of ventricles at the end of diastole

A

preload

204
Q

what does the Frank-Starling mechanism measure?

A

the relationship between EDV and SV

205
Q

the main determinent of the length of the cardiac muscle fiber (sarcomere) is:

A

the degree of diastolic filling (aka: preload)

206
Q

the strength of contraction at any given EDV

A

contractility

207
Q

the fraction of the EDV that is ejected

A

ejection fraction

208
Q

what is the equation for the ejection fraction?

A

EF = SV / EDV

209
Q

how does sympathetic stimulation affect contractility?

A

it increases contractility

210
Q

do epinephreine/norepinephrine increase or deacrease contractility of the heart?

A

increase

211
Q

tension (or arterial pressure) against which the ventricles contract

A

afterload

212
Q

what happens to the stroke volume as the afterload increases?

A

SV decreases

213
Q

any factor that restricts blood flow through the arterial system will ________ afterload

A

increase

214
Q

the endothelium of vessels is continuous with:

A

the endocardium of the heart

215
Q

smooth, single-celled layer of endothelial cells

A

endothelium

216
Q
  • many elastic fibers, few smooth muscle cells
  • expand and recoil in response to pressure changes
    these are characteristics of:
A

elastic arteries

217
Q
  • many smooth muscle cells, few elastic fibers
  • distribute blood
    these are characteristics of:
A

muscular arteries

218
Q
  • 1-2 layers of smooth muscles
  • resistance vessels
    these are characteristics of:
A

arterioles

219
Q

which is higher: pulmonary vascular resistance or systemic vascular resistance

A

systemic vascular resistance

220
Q

what are the two main functions of the arterioles?

A

1) regulate blood flow to organs
2) determine mean arteriole pressure (MAP)

221
Q

relaxation of arteriolar smooth muscle; increases blood flod to organs

A

vasodilation

222
Q

contraction of arteriolar smooth muscle; decreases blood flow to organs

A

vasoconstriction

223
Q

arterioles are high resistance vessels due to:

A

their small size

224
Q

true or false: both extrinsic and intrinsic factors can alter basal tone

A

true

225
Q

what are the extrinsic factors which can alter basal tone?

A

nerves and hormones

226
Q

what are the intrinsic factors which can alter basal tone?

A

local controls: organs and tissues alter their own arterioloar resistances independent of nerves/hormones

227
Q

norepinephrine causes _______ in the arterioles

A

vasoconstriction

228
Q

nitric oxide causes _______ in the arterioles

A

vasodilation

229
Q

epinephrine from the adrenal medulla can cause _______ or ______ in the arterioles

A

vasoconstriction, vasodilation

230
Q

arteriolar smooth muscle is sensitive to local chemical changes, which are the result of:

A

chances in metabolic activity

231
Q

what is hyperemia?

A

an excess of blood in the blood vessels

232
Q

increased metabolic activity results in _______ of arterioles and _______ blood flow

A

vasodilation, increased

233
Q

arterioles change theri resistance to maintain constant blood flow in the presence of a:

A

pressure change

234
Q

what are the two local controls which alter arteriolar resistance?

A
  • active hyperemia
  • flow autoregulation
235
Q

flow autoregulation may also be mediated by the:

A

myogenic response

236
Q

direct response of arteriolar smooth muscle to stretch

A

myogenic response

237
Q

how thick are capillaries?

A

one endothelial cell thick

238
Q

is there smooth muscle or elastic tissue in capillaries?

A

no

239
Q

what is the function of capillaries?

A

the site of exchange of material between blood and interstitial fluid

240
Q

narrow, water-filled space at the junctions between cells

A

intercellular clefts

241
Q

made up of glycoproteins, provides support and capillary attachment

A

basement membrane

242
Q

true or false: capillaries can be made up of one or more endothelial cells

A

true

243
Q

what are the three types of capillaries?

A

1) continuous capillaries
2) fenestrated capillaries
3) sinusodal capillaries

244
Q

the type of capillary where endothelial cells form an uninterrupted tube, surrounded by complete basement membrane

A

continuous capillaries

245
Q

the continuous capillaries are the site of exchange of:

A

water, small solutes, and lipid-soluble materials

246
Q

where are continuous capillaries present?

A

most tissues

247
Q

pores that penetrate the endothelial lining

A

fenestrae

248
Q

fenestrated capillaries are surrounded by a:

A

complete basement membrane

249
Q

fenestrated capillaries are the site of rapid exchange of:

A

water and solutes

250
Q

where are fenestrated capillaries present?

A

endocrine organs, choroid plexus, GI tract, kidneys

251
Q

discontinuous capillaries; flattened and irregularly shaped capillaries

A

sinusoids

252
Q

where are sinusodal capillaries located?

A

liver, bone marrow, and spleen

252
Q

sinusodal capillaries are the site of exchange of:

A

water, solutes (red blood cells, debris, proteins)

253
Q

the use of vesicles to cross endothelial cells

A

transcytosis

254
Q

transcytosis occurs at the:

A

intercellular clefts, fenestrae, and fused vesicle channels

255
Q

movement of protein-free plasma across the capillary wall

A

bulk flow

256
Q

movement of protein-free plasma from capillary ro interstitial fluid

A

filtration

257
Q

movement of protein-free plasma from interstitial fluid to capillary

A

reabsorption

258
Q

pressures that drive fluid movement into and out of the capillary

A

hydrostatic pressure

259
Q

fluid pressure exerted on the outside of the capillary wall by itnerstitial fluid, favours fluid movement into the capillary

A

interstitial fluid hydrostatic pressure

260
Q

which is negligible, capillary hydrostatic pressure or interstitial fluid hydrostatic pressure

A

IF hydrostatic pressure

261
Q

osmotic pressure due to non-permeating plasma proteins inside the capillaries, favours fluid into capillaries

A

blood colloid osmotic pressure

262
Q

small amount of plasma proteins may leak out of the capillaries into the interstitial space (negligible)

A

interstitial fluid collid osmotic pressure

263
Q

positive filtration pressures favour:

A

filtration

264
Q

negative filtration pressures favour:

A

absorption

265
Q

transition point between filtration and reabsorption lies closer to ________ end of capillary

A

venous

266
Q

the pressure needed to drive blood into tissues

A

mean arterial pressure (MAP)

267
Q

how is mean arterial pressure calculated?

A

MAP = diastolic pressure + (pulse pressure/3)
OR
MAP = cardiac output (CO) * total peripheral resistance (TPR)

268
Q

what is the average arterial pressure during one cardiac cycle

A

~90 mmHg

269
Q

is there enough pressure to move blood at 60 mmHg?

A

no

270
Q

pulse pressure ________ as distance from the heart ________

A

decreases, increases

271
Q

mean arterial pressure _______ as distance from heart _______

A

decreases, increases

272
Q

largest drop in pressure occurs across the ________

A

arterioles

273
Q

why is there such a dramatic decrease in pressure at the arterioles?

A

parallel flow

274
Q

what is the average systolic/diastolic pressure?

A

120/80 mmHg

275
Q

how is pulse pressure calculated?

A

pulse pressure = systolic - diastolic

276
Q

maximum blood pressure during ventricular systole?

A

systolic pressure

277
Q

minimum blood pressure at the end of ventricular diastole?

A

diastolic pressure

278
Q

a condition characterised by chronically increased arterial blood pressure

A

hypertension

279
Q

a condition characterized by abnormally low blood pressure

A

hypotension

280
Q
  • seconds to hours
  • baraoreceptors reflexes
  • adjusts cardiac output and total peripheral resistance
    these are characteristics of:
A

short-term regulation of MAP

281
Q
  • adjust blood volume
  • restore normal salt and water balance through mechanisms that regulate urine output and thirst
    these are characteristics of:
A

long-term regulation of MAP

282
Q

mechanoreceptors found in major artery walls

A

baroreceptors

283
Q

respond to changes in pressure when walls of vessel stretch/relax

A

baroreceptors

284
Q

when looking at baroreceptor action potential frequency, the rate ofdischarge is proportional to:

A

the mean arterial pressure

285
Q

the medullary cardivascular center (medulla oblongata) receives input from:

A

baroreceptors

286
Q

the medullary cardiovascular center alters _______ stimulation to the heart and _______ stimulatio to the heart, arterioles and veins

A

parasympathetic (vagal), sympathetic

287
Q

baroreceptors adapt to sustained changes in:

A

arterial pressure

288
Q

pressure volume loops are generated by real-time measurement of pressure and volume within the:

A

left ventricle

289
Q

on a pressure volume loop, the slope of the line tangential to the point where the aortic valve closes is the:

A

end-systolic pressure-volume relation (ESPVR)

290
Q

describes the maximal pressure that can be developed by the ventricle at any given left ventricular volume

A

end-systolic pressure-volume relation (ESPVR)

291
Q

does increasing the preload increase the ESPVR?

A

no

292
Q

does increasing contractility increase the ESPVR?

A

yes

293
Q

does increasing the afterload increase ESPVR?

A

no

PHYSL 212 (8 decks)

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