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Exercise Physiology > Cardiovascular > Flashcards

Cardiovascular Flashcards

1
Q

what is the sequence of events through the hear in one beat

A

1) SA node
2) Atria
3) AV node
4) AV bundle (of His)
5) Purkinje fibers
6) Ventricles

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2
Q

there is a time delay of __s from atria to ventricle

A

about 0.1second

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3
Q

___ transmits signal __X faster then normal ventricular fibers

A

purkinje fibres

6X

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4
Q

where are most of the parasympathetic nerve endings concentrated in the heart

A

atria

including the SA and AV nodes

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5
Q

the ____ fibres supply the SA and AV nodes and the muscle of the atria and ventricles

A

sympathetic nerve fibers

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6
Q

the contents of the vascular system could wrap around the world ___X

A

4

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7
Q

what are the three most basic roles of the cardiovascular system? provide an example for each

A

1) to transport nutrients to tissues (oxygen, glucose, lipids, amino acids)
2) to remove metabolic by-products from tissue (CO2, H+)
3) to transport hormones so they can exert their effects on target tissues

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8
Q

what are three limitations of the maximal rate of blood flow to metabolically active tissue

A

1) the heart has a limit with respect to the maximal amount of blood that it can pump each min (max CO)
2) there is a limited amount of total blood volume within the circulatory system that must perfuse a lot of different tissues
3) there is a limited density of capillaries in each different type of tissue, which directly limits the perfusion of that tissue

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9
Q

what is the cardiovascular system

A

a series of pipes (arteries, capillaries, veins) that enable the heart to pump blood through the different tissues of the body

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10
Q

what are the cardiovascular system components

A

a pump
a high pressure distribution circuit
exchange vessels
a low pressure collection circuit

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11
Q

the right side of the heart receives oxygen____ blood

A

receives oxygen poor

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12
Q

where does the right side of the heart get its blood

A

gets poor oxygenated blood from the body and pumps it to the lungs

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13
Q

where does the blood come from the body into the right side of the heart

A

superior and inferior vena cava

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14
Q

after flowing through the inferior and superior vena cava where does the blood go

A

into the right atria

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15
Q

from the right atria the blood goes through ___ valve into __

A

tricuspid valve

right ventricle

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16
Q

from the right ventricle the blood goes through ___ valve into the ____

A

pulmonary valve

pulmonary arteries to the lungs

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17
Q

the left side of the heart receives ____ blood

A

oxygenated blood

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18
Q

where does the left side of the heart get its blood

A

the lungs

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19
Q

where does the oxygenated blood come from

A

the pulmonary veins

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20
Q

where does the oxygenated blood go from the pulmonary veins

A

into the left atria

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21
Q

from the left atria the blood goes through __ valve into __

A

mitral valve

left ventricle

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22
Q

from the left ventricle the blood goes through ___ valve into the ___

A

aortic valve

aorta to the body

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23
Q

___ regulate the flow of blood through the chambers of the heart

A

valves

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24
Q

what influences the opening/closing of the valves

A

the pressure the heart creates when it contracts

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25
Q

the opening and closing of valves regulate ____ through the chambers of the heart

A

blood flow

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26
Q

the left ventricle starts to fill with blood when the ____ valve opens

A

mitral (bicuspid) (left side of heart)

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27
Q

it takes a lot of pressure to open the ____ valve

A

aortic

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28
Q

exercise is a good example of how simultaneous changes in factors influence the ___ ____ and ____

A

1) the pressure volume loop
2) affect ventricular pressures
3) affect volumes

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29
Q

during whole body exercise increased ____ to the heart generally causes a small increase in _____ volume

A

venous return

end-diastolic volume

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30
Q

_____ nerve system activates the heart and increases ventricular inotropy which ____ end systolic volume

A

sympathetic

decreases

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31
Q

increased venous return and the activation of the sympathetic nervous system to increase ventricular inotropy and decrease end-SYSTOLIC volume leads to___

A

a small increase in end-DIASTOLIC volume
and
a large reduction (decrease) in end- SYSTOLIC volume

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32
Q

the increase in end-DIASTOLIC volume and the decrease in end-SYSTOLIC volume leads to ___

A

an INCREASE in stroke volume and ejection fraction

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33
Q

why does the increase in atrial pressure that usually increases end-systolic volume and decrease stroke volume NOT occur

A

because the large increase in inotropy is the dominate factor affecting end systolic volume and stroke volume

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34
Q

what does the right coronary artery supply blood to

A

the right atrium right ventricle
the bottom portion of the left ventricle
back of the septum

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35
Q

what does the coronary veins do

A

take oxygen poor blood that has already been used by muscles of the heart and return it to the right atrium

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36
Q

what does the left anterior descending artery supply blood to

A

the front and bottom of the left ventricle

front of the septum

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37
Q

what does the circumflex artery supply blood to

A

the left atrium and the side and back of the left ventricle

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38
Q

what does the left coronary artery do

A

divides into two branches

the circumflex artery and the left anterior descending artery

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39
Q

the heart feeds itself through

A

coronary circulation

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40
Q

what does the great cardiac vein do

A

returns deoxygenated blood from the anterior surfaces of the LEFT ventricle

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41
Q

what does the anterior cardiac veins do

A

group of parallel coronary veins that course over the anterior surface of the right ventricle, draining it and entering directly into the right atrium

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42
Q

what is the coronary sinus

A

the coronary sinus is a collection of veins joined together to form a large vessel that collects blood from the heart muscle (myocardium).

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43
Q

what does the coronary sinus deliver

A

less-oxygenated blood to the right atrium as do the superior and inferior vena cava

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44
Q

myocardium has a very high content of ____ and capillaries density

A

mitochondria

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45
Q

the heart muscle tissue (myocardium) is ____ muscle

A

striated

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46
Q

the arterial system is the ____ pressure distribution circuit

A

HIGH

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47
Q

what does the arterial system compose of

A

arteries

arterioles

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48
Q

conduit artery

A

designed to transport blood to areas of the body

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49
Q

feed artery

A

vascular resistance vessels designed to regulate flow to specific areas of the body

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50
Q

feed arteries account for ____% of TPR

A

50%

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51
Q

terminal arteriole

A

the last control point for regulating blood flow into capillaries. therefore to perfuse a microvascular unit the terminal arteriole MUST be DIALATED

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52
Q

what is the microvascular unit

A

all of the capillaries arising from a common terminal arteriole

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53
Q

do all three energy systems happen in all types of situations

A

YES

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54
Q

_____ are considered to be the primary location where oxygen transfer occurs in muscles

A

capillaries

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55
Q

there is no VSM in capillaries rather there is only an endothelial layer that promotes __

A

diffusion by limiting the distance that oxygen must diffuse

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56
Q

a tubes resistance is inversely proportional to the ___ power of its radius

A

4th power

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57
Q

smooth muscle fibres in arterioles control ____

A

blood flow to capillary beds

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58
Q

osmotic pressure within capillaries ___

A

draws fluid back

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59
Q

____ forces fluid from capillary

A

blood pressure

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60
Q

the precapillary sphincter is

A

a ring of smooth muscle that controls capillary diameter

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61
Q

at rest ___ per min in muscle tissue

A

5 ml/100g

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62
Q

veins are the ___ pressure collection and return circuit

A

LOW

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63
Q

valves are important for

venous return

A

one way flow and important for the milking action produced by skeletal-muscle pump

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64
Q

low pressure of the venous system is potentially problematic for ___ called ____

A

blood return

venous pooling

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65
Q

___ plays a role in venous pooling

A

force of gravity

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66
Q

an issue when standing at attention in an upright posture when skeletal muscle contraction is limited can lead to

A

pooling of blood, reduced return, decreased end diastolic volume which leads to decreased stroke volume and decreased Q which leads to fainting

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67
Q

venous return (low pressure of the venous system) is countered by

A

1) skeletal muscle pump
2) respiratory pump
3) venoconstriction

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68
Q

explain skeletal muscle pump and venous return

A

muscular contractions assist with venous return

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69
Q

explain respiratory pump and venous return

A

changes in pressure gradients

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70
Q

explain venoconstriction and venous return

A

constriction or narrowing of small veins/venules draining muscles ( controversial)

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71
Q

what component has the most influence on blood pressure

A

arterioles

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72
Q

_____ are the last control point for regulating blood flow into capillaries

A

terminal arterioles

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73
Q

to perfuse a MVU the ____ must be ____

A

terminal arteriole

dilated

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74
Q

explain the left ventricle blood pressure

A

swings between a low pressure of 0mmHg during diastole to a high pressure of 120mmHg during systole

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75
Q

in the left ventricle when is the pressure the lowest

A

during diastole

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76
Q

in the left ventricle when is the pressure the highest

A

during systole

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77
Q

arterial blood pressure fluctuates between a peak systolic pressure of ___ and a low diastolic pressure of ___

A

120mmHg

80mmHg

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78
Q

do the large arteries have the same or different magnitude throughout

A

the same

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79
Q

why does the pressure drop precipitously and the systolic to diastolic swings in pressure are converted to nonpulsatile pressure when blood flows through the arterioles

A

because of the arterioles high resistance

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80
Q

the pressure continues to decline but at a slower rate as blood flows through the ___

A

capillaries and venous system (venules and veins)

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81
Q

local blood flow is directly regulated by ___

A

blood pressure and local vascular resistance

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82
Q

what is ohms law

A

increase blood flow= the change in pressure/resistance

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83
Q

what is the change of pressure in ohms law

A

volume pushing against arteriole wall

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84
Q

what is the resistance in ohms law

A

resistance within the vessel is proportional to the size of the arteriole

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85
Q

systemically total peripheral resistance is increased during ___ however local metabolic factors in active tissues promote regional vasodilation therby ____

A

exercise

enhancing local blood flow

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86
Q

what directly influences local blood flow

A

vessel radius

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87
Q

a vessel with a greater radius will have greater blood flow or worse

A

better!

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88
Q

a vessel with greater radius will have more or less resistance then a smaller radius vessel

A

smaller resistance

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89
Q

the diameter of resistance vessels (feed arteries and arterioles) is controlled by __

A

vascular smooth muscle

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90
Q

____ nerve fibres surround feed arteries, primary arterioles and terminal arterioles

A

sympathetic

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91
Q

the systemic increase in total peripheral occurs in response to ____

A

SNS signalling via norepinephrine and epinephrine induced vascocontriction throughout most of the tissues in the body

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92
Q

why do the arterioles in the brain not vasoconstrict

A

do not have alpha1 receptors and will not vasocontrict due to catecholamines

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93
Q

one of the most fundamental principals of circulatory function is the ability of

A

each tissue to control its own local blood flow in proportion to its metabolic demand

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94
Q

does cardiac output increase during exercise

A

yes

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95
Q

the percentage of cardiac output going to the skeletal muscle and heart rises thereby delivering

A

extra o2 and nutrients needed to support these muscles stepped-up rate of ATP consumption

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96
Q

why does a percentage of the cardiac output increase in the skin

A

as a way to eliminate from the body surface the extra heat generated by the exercising muscles

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97
Q

what is the only tissue that the magnitude of blood flow remains unchanged as the distribution of cardiac output is readjusted during exercised

A

the brain

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98
Q

systolic blood pressure is

A

the work of the heart and force that blood exerts against the arteriole walls during ventricular systole

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99
Q

systolic blood pressure is the CLOSING of the ____

A

aortic valve

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100
Q

diastolic blood pressure is

A

an indication of peripheral resistance or ease that blood flows from the arterioles into the capillaries

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101
Q

diastolic blood pressure is the OPENING of the ___

A

aortic valve

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102
Q

mean arteriole pressure is

A

the average pressure in a persons arteries during one cardiac cycle

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103
Q

what is considered a better indicator of perfusion to vital organs; systolic blood pressure or mean arteriole pressure

A

mean arteriole pressure

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104
Q

pulse pressure is

A

the difference between systolic blood pressure and diastolic blood pressure

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105
Q

MAP=

A

diastolic BP + [0.333*(pulse pressure)]

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106
Q

pulse pressure =

A

systolic BP-diastolic BP

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107
Q

does the heart remains in diastole or systole longer

A

diastole by 2/3 longer (which is why there is a 0.333 in MAP equation)

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108
Q

what is normal blood pressure

A 
systolic = 120 
diastolic = 80
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109
Q

what is prehypertension blood pressure

A 
systolic = 120-139
diastolic = 80-89
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110
Q

what is stage 1 hypertension blood pressure

A 
systolic = 140-159
diastolic = 90-99
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111
Q

what is stage 2 hypertension blood pressure

A 
systolic = 160
diastolic = 100
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112
Q

hypertension leads to

A 
atherosclerosis
heart disease
congestive heart failure
kidney disease
myocardial infarction 
stroke
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113
Q

what is treatment of hypertension

medication

A

medication

  • beta blockers (reduce contractility and slow HR)
  • alpha & Ca blockers (dilate blood vessels)
  • diuretics (increase renal excretion)
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114
Q

what is treatment of hypertension

lifestyle changes

A 
exercise 
weight loss
stress management 
cessation of smoking
reduce alcohol intake
reduce sodium intake
ensure adequate potassium 
calcium and magnesium intake
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115
Q

it is the balance of local substances that regulates

A

arteriole diameter and thereby the local tissue perfusion

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116
Q

what are the major factors affecting arteriolar radius

A

local metabolic changes in o2 and other metabolites

sympathetic activity

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117
Q

the sympathetic activity affecting arteriolar radius is ___ control

A

extrinsic

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118
Q

the local metabolic changes in o2 and other metabolites affecting arteriolar radius is ____ control

A

local or intrinsic control

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119
Q

what are extrinsic control mechanisms

A

epinephrine and norepinephrine

angiotensin 2

vasopressin

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120
Q

what are local control mechanisms

A

histamine release

heat, cold application

myogenic responses to stretch

response to sheer stress

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121
Q

what is the difference between thrombus and plaque

A

thrombus= complete blockage

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122
Q

what is the percutaneous transluminal coronary angioplasty

A

double-lumen dilation catheter

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123
Q

what is the revascularization option

A

coronary artery bypass graft surgery

  • mammary artery
  • saphenous vein
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124
Q

the myocardium relies almost exclusively on energy produced through ____ metabolism

A

aerobic (oxygen)

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125
Q

the heart will use ____ fuel source it receives in the blood to fuel aerobic metabolism

A

whatever!

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126
Q

typically at rest ____ are the primary source of fuel

A 
fatty acids (60-65%)
glucose (30%)
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127
Q

after a meal the heart may ____ its use of ____ or fatty acids based on their availability

A

increase

glucose

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128
Q

as exercise intensity increases the myocardium becomes more reliant on ___ because ___ becomes more available in the blood as it is released from working muscles

A

lactate

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129
Q

blood glucose fatty acids and lactate enter the myocardium and are then used in ____ metabolism by entering the ___ in the mitochondria

A

aerobic

TCA (Krebs cycle)

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130
Q

where does the krebs cycle take place

A

mitochondria

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131
Q

myocardial workload is estimated by the

A

rate pressure product

132
Q

what is the rate pressure product equation

A

SBP X HR

133
Q

rate pressure product is a common method used to estimate

A

myocardial workload (or myocardial oxygen utilization)

134
Q

what does the RPP measure

A

myocardial O2 consumption and coronary blood flow in healthy individuals

135
Q

RPP is correlated with the onset of ____ in patients with coronary heart disease

A

angina

136
Q

exercise training lowers ___ and ___ at a specific work rate,

A

HR and SBP

137
Q

why does exercise training lower HR and SBP at a specific work rate

A

because the body adapts to exercise over time and better uses aerobic metabolism which thereby reduces the oxygen needed to conduct the required work rate

138
Q

what is cardiac output =

A

HR x SV

139
Q

increasing exercise intensity causes HR and SV to _____ and there for increase _____

A

increase

cardiac output

140
Q

increasing exercise intensity increases heart rate. how does this happen

A

parasympathetic signalling decreases

sympathetic signalling increases

141
Q

the decrease in parasympathetic happens because the decrease in the ________ nerve stimulation

A

vagal

142
Q

the increase in sympathetic signalling happens because of the increase in _____and ____

A

norepinephrine

epinephrine

143
Q

why does stroke volume increase in response to increasing exercise intensity

A

increase in filling due to venous return

increase in contractility (frank starling)

144
Q

why does blood pressure increase in response to increasing exercise intensity

A

the increase in cardiac output

the increase in systemic total peripheral resistance

145
Q

intrinsic regulation of the heart

A

sinoatrial node

without modulation of the SA node will depolarize 100 times per minute

146
Q

extrinsic regulation of the heart

A

neural output and chemical messengers in the blood both influence the extrinsic regulation of the heart rate and the circulatory system

147
Q

SA node is where in the heart

A

situated in the posterior wall of the right atrium, the SA node is an intrinsic pacemaker

148
Q

the SA node depolarizes and repolarizes to provide

A

constant stimulus to the heart

149
Q

AV node and (bundle of his) is located where

A

situated close to the tri-cuspid valve

150
Q

what does the AV node do

A

transmits the depolarization to the purkinje fibers through both ventricles

151
Q

where are the purkinje fibers and what do they do

A

specialized conducting fibers that transmit the electrical depolarization through the left and right ventricles

152
Q

it takes a small amount of time for the depolarization to move from the SA node to both ventricles because the _____

A

purkinje fibers

153
Q

how long is the delay in the left atria take after the SA node

A

0.03-0.09 seconds

154
Q

how long is the delay in the left ventricle after the SA node

A

0.16-0.22 seconds

155
Q

how long is the delay in the right ventricle after the SA node

A

0.17-0.19 seconds

156
Q

the cardiac rhythm is a complex series of electrical signals that are regulated by the

A

cardiac conduction system

157
Q

what is the sequence of the cardiac conduction system

A 
sinoatrial node 
atrioventricular node
atrioventricular bundle of his
left and right bundle branches
bundle branches
158
Q

what are the points of the (ECG) electrocardiogram

A

P wave
QRS complex
T wave
refractory period

159
Q

what is the P wave

A

represents the depolarization of the atria

160
Q

how long does the p wave last

A

0.15 seconds

161
Q

what does the P wave signal

A

atrial contraction

162
Q

what is the QRS complex

A

follows the P wave and signals electrical changes from ventricular depolarization and ventricles contraction

163
Q

what is the T wave

A

represents ventricular REPOLARIZATION and occurs during ventricular diastole (relaxation)

164
Q

during the T wave can another contraction occur? if not how long till it can contract again

A

no other contractions can occur

for 0.20-0.30 seconds

165
Q

what is the refractory period

A

allows the ventricles time to refill

166
Q

what does the wave form of the ECG does not represent

A

the intrinsic pacemaker activity of a single heart cell

167
Q

what is the ECG

A

the sum of the electrical activity of all cell types in the heart

168
Q

atrial depolarization is recognized by the ____ on the ECG

A

p wave

169
Q

what is the P-R interval

A

the electrical transmission from atria to ventricles

170
Q

ventricular depolarization is recognized by the ___ on the ECG

A

QRS complex

171
Q

what does the R wave indicate

A

the initial positive deflection

172
Q

what does the Q wave indicate

A

the negative deflection before the R wave

173
Q

what does the S wave indicate

A

the negative deflection following the R wave

174
Q

what is the ST segment

A

ventricular repolarization

175
Q

what is the Q-T interval

A

ventricular depolarization

and repolarization

176
Q

what is the stress test on the ECG

A

arrhythmia

S-T segment

177
Q

what does a depressed S-T segment represent on the ECG

A

pre ventricular contraction

178
Q

ECG can be used to identify changes in the electrical rhythm of the heart to identify ___

A

the general area of the heart that is causing the pathological change in electrical rhythm

179
Q

what is a arrhythmias

A

changes in the normal rate or rhythm of heartbeat

180
Q

causes of arrhythmias

A

SA node dysfunction
usually associated with hypothyroidism, advanced liver disease, hypothermia, acute hypertension, and typhoid fever

defects in impulse conduction

181
Q

types of arrhythmias

A 
sinus bradycardia 
sinus tachycardia
conduction defects (heart blocks) 
atrial and ventricular premature complexes
flutter
fibrillation
182
Q

signs and symptoms of arrhythmias

A

fatigue from cardiac output, dizziness, fainting (bradycardia)

irregular heart rate (flutters and fibrillations)

183
Q

medical surgical treatment of arrhythmias

A

implantation of a pacemaker
antiarrhythmic drugs
defibrillators

184
Q

how does heart rate pressure and ECG all fit together

A

if you align the events recorded for ECG, left ventricular pressure and left ventricular volume it is easier to see how these different parameters measure different properties of the same event

185
Q

what factors affect heart rate

A

the autonomic nervous system (PNS + SNS) controls heart rate by modulating the intrinsic pacemaker activity of the heart

186
Q

what influences extrinsic regulation

A

neural input and chemical messengers in the blood that influence the extrinsic regulation of the heart rate and circulatory system

187
Q

what is the extrinsic neural input regulation

A

sympathetic and parasympathetic

188
Q

what are the sympathetic receptors

A

alpha adrenergic and beta adrenergic

189
Q

what are the sympathetic catecholomines

A

epinephrine and norepinephrine

190
Q

what are the neural chronotropic effects

A

increase heart rate by accelerating how easy it is to depolarize the SA node

191
Q

what are the neural inotropic effect

A

increase how strongly the heart contracts to increase stroke volume
also promotes increased vasoconstriction throughout the circulatory system to increase total peripheral resistance

192
Q

parasympathetic input occurs from the

A

vagus nerve

193
Q

what are the parasympathetic catecholomines

A

acetylcholine

194
Q

what does acetylcholine do to the heart rate

A

decreases heart rate by making it more difficult to depolarize the SA node

195
Q

what are chemical messengers

A

factors in the blood influence regulate cardiovascular function

196
Q

the intrinsic pacemaker activity of the heart is usually controlled by the

A

depolarization of SA node pacemaker cells

197
Q

how does the autonomic nervous system influence heart rate

A

by modulating how quickly the different ions move across the cell membrane- which results in a change in heart rate

198
Q

what is the overall membrane potential the sum of

A

the movement of different ions across the cell membrane during each heart beat

199
Q

sympathetic signalling increases how quickly pacemaker cells _____

A

depolarize to increase heart rate

200
Q

parasympatheric signalling slows how quickly pacemaker cells depolarize to

A

reduce heart rate

201
Q

the cardiovascular control center rapidly regulates the functional parameters of the circulatory system by incorporating ____ input from the ______ and feedback from the ____

A

feedforward
central command
periphery

202
Q

where is the cardiovascular center

A

the ventrolateral medulla

203
Q

signals from the ____ central center continually modulate the activity of the cardiovascular control center

A

somatomotor

204
Q

what is a feed forward mechanism that rapidly adjusts the regulation of heart rate and blood vessels to optimize tissue perfusion and blood pressure

A

input from the central command

205
Q

the central command influences the ____ regulation of the cardiovascular system

A

neural

206
Q

how is the preexercise anticipatory response activated

A

activation of the central command from motor cortex and higher area of the brain increase in sympathetic outflow and reciprocal inhibitions of parasympathetic activity

207
Q

how is the pre exercise anticipatory responded to

A

acceleration of heart rate; increased myocardial contractility; vasodilation in skeletal and heart muscle; vasoconstriction in other areas especially skin gut spleen, liver and kidneys; increase in arterial blood pressure

208
Q

what is the feedback from the periphery

A

the cardiovascular center receives reflex sensory feedback from the periphery through a variety of sensors in blood vessels, joints and muscles

209
Q

what are baroreceptors

A

sense the blood pressure (stretch) and relay the information to the brain so that a proper blood pressure can be maintained

210
Q

baroreceptors are a type of what sensory neuron

A

mechanoreceptors

211
Q

where are arterial baroreceptors located

A

in the aortic arch and in the carotid arteries

212
Q

what do the arterial baroreceptors do

A

reflex acts to influence sympathetic nerve signalling when blood pressure needs to be regulated

213
Q

operating points for the arterial baroreceptors reset during exercise to accommodate

A

central blood pressure to sufficiently perfuse metabolically active tissue

214
Q

where are cardiopulmonary baroreceptors located

A

in the left ventricle, right atrium, and large veins

215
Q

what do the cardiopulmonary baroreceptors do

A

monitor changes in pressure in the heart chambers and pulmonary vasculature

216
Q

what is carotid artery palpitation

A

external pressure against the carotid artery sometimes slows heart rate due to the addition of pressure to the carotid baroreceptor

217
Q

why might the carotid artery palpitation give an inaccurate reading in comparison to the radial artery

A

the external pressure against the artery sometimes causes the heart rate to slow down so after exercise if someone checks their carotid artery pulse they might get a lower then accurate HR

218
Q

what are the three skeletal muscle ergoreceptors

A

mechanoreceptors
chemoreceptors
metaboreflex

219
Q

what are mechanoreceptors

A

sense the physical state of muscle (determine if it is contracting)

220
Q

what are chemoreceptors

A

sense metabolites that are created during contractions

221
Q

what are metaboreflex

A

turned on when metabolites accumulate in the interstitial space of muscle during contractions

222
Q

what do all three ergorecpeptors influence

A

parasympathetic and sympathetic signalling

223
Q

what do all three ergoreceptors feedback to the cardiovascular control center is mediated by group of

A

iii and iv afferents

224
Q

what does the exercise pressor reflex refer to

A

these neural regulatory mechanisms that sense muscle activity and use that information to provide feedback to better match sympathetic and parasympathetic signalling with the required level of cardiovascular control

225
Q

what is the activator of the neural regulation of the cardiovascular system during exercise

A

parasympathetic withdrawal at onset and during low intensity exercise
sympathetic stimulation
reflex feedback from peripheral mechanical and chemical receptors ect..

226
Q

what is the response of neural regulation of the cardiovascular system during exercise

A

further dilation of muscle vasculature

constriction of vasculature in inactive tissues to maintain adequate perfusion pressure throughout arterial system

vasoconstriction, muscle pump ect…

227
Q

what is Poiseuille’s law

A

flow= Blood pressure gradient x vessel radius^4/vessel length x fluid viscosity

228
Q

a small change in blood vessel radius has a very large impact on

A

flow

229
Q

what factors stimulate a vasodilation of arterioles to increase blood flow

A

metabolite accumulation or the lack of oxygen in muscle

hormonal factors such as catecholomines

shear stress flow causing things to rub against the endothelial wall

230
Q

the exchange system is in the

A

capillary bed

231
Q

at rest how many capillaries are open

A

1 out of every 30

232
Q

during exercise the pre-capillary sphincters open in response to what

A

local metabolite accumulation

233
Q

what does the open sphincters and the local metabolite accumulation lead to

A

increased tissue blood flow (perfusion)
delivers a large volume of oxygenated blood with minimal changes in cardiovascular regulation
increases the surface area for exchange of gases, nutrients and waste

234
Q

what are the roles of nitric oxide

A

vasodilation occurs when nitric oxide penetrates smooth muscle cells

235
Q

where does nitric oxide come from

A

ycern elial cells within blood vessels release nitric oxide gas- its either released by autonomic neurons or from drugs like Viagra or ntrg

236
Q

how does sheer stress stimulate the release of nitric oxide from the cells

A

the red blood cells bumping into the epithelial cells cause the cell to deform which triggers the release of nitric oxide

237
Q

normally nitric oxide is able to promote vasodilation when will this not occur

A

in many disease states causes nitric oxide to be reduced due to an accumulation of oxidative stress which impairs vasodilation

238
Q

what are some example pathological conditions that reduce nitric oxide

A

hypercholesterolemia
atherosclerosis
peripheral artery disease
coronary artery disease

239
Q

what is nitric oxide bioavailability

A

the total amount of nitric oxide that is biologically active and is the difference between the total production of nitric oxide minus the total amount of nitric oxide destroyed by other processes

240
Q

the excess O2 combines with NO (nitric oxide) to create___ what is it

A

ONOO

damages cellular proteins

241
Q

exercise training and some other medical treatments enhance endothelial function by promoting what

A

an increase in nitric oxide bioavailability

242
Q

exercise increases eNOS (endothelial nitric oxide synthase) protein expression that leads to

A

enhanced NO bioavailability (increased vasodilation)

243
Q

exercise may reduce the amount of ____ made by NADP(H) oxidase

A

reactive oxygen

244
Q

exercise enhances ____ protein expression which reduces oxidative stress

A

SOD

superoxide dismutase

245
Q

why does HR not very much in a heart transplant patient

A

because the neurons don’t connect like they use to

there is no more neural innervation

246
Q

how is heart rate regulated in a heart transplant patient

A

hormonal feedback from circulating catecholamines

247
Q

patients who receive a heart transplant tend to have higher VO2max post surgery why

A

because the healthy heart tends to have higher stroke volume then the original diseased heart so the transplant heart tends to increase stroke volume in a linear way throughout exercise

248
Q

a typical VO2max for patients who require a heart transplant is 10-15l O2/kg/min after transplantation the VO2max tends to increase by roughly

A

50-60%

249
Q

what is cardiac output

A

can be thought of as the flow of blood from the heart or as the amount of blood pumped out of the heart during a 1 min period

250
Q

what does Q represent

A

flow or cardiac output

251
Q

what is the cardiac output equation

A

cardiac output = HR x SV

252
Q

what are three other methods also typically used to determine cardiac output

A

direct fick
indicator dilution
CO2 rebreathing
(none of these methods use heart rate or stroke volume to determine Cardiac Output)

253
Q

what is the principle of the Fick Equation

A

if you know the average difference between oxygen content of arterial and venous blood and how much oxygen was utilized by that working muscle

254
Q

what is the only thing not known in the fick equation

A

how much blood was delivered to the working muscle to supply that amount of oxygen

255
Q

what is the direct fick equation

A

Q= [VO2/a-v O2 difference]x100

256
Q

what is the indicator dilution method

A

determining flow through a tube. the volume per min flowing in the tube equals the quantity of indicator injected divided by the average dye concentration at the sample site multiplied by the time between the appearance and disappearance of the dye

257
Q

what is the indicator dilution method equation

A

Q= [quantity of dye injected/(average concentration of the dye in the blood for duration of curve x duration of curve)]

258
Q

what is CO2 rebreathing

A

the use of a rapid CO2 gas analyzer to measure mixed venous and arterial CO2 levels
breath by breath analysis
non-invasive (bloodless)
however this test is only useful when the person is doing steady state exercise

259
Q

what is the CO2 rebreathing equation

A

Q= [VCO2/v-a CO2 didderence]x100

260
Q

cardiac output will provide blood flow in proportion to the bodys

A

metabolic demands

261
Q

with increase in metabolic demand cardiac output _______

A

increases linearly with oxygen uptake

262
Q

women typically have cardiac output and stroke volume that are about ____% lower then men

A

25

263
Q

what is cardiac output for sedentary individual

A

25Lmin-1

264
Q

what is cardiac output for the well trained individual

A

30-35Lmin-1

265
Q

what is the cardiac output for the world class athletes

A

35-40Lmin-1

266
Q

cardiac output increases directly with _____ until when

A

exercise intensity

until the delivery of oxygen matches the metabolic demands of the metabolically active tissue

267
Q

what is the average persons stroke volume at rest

A

80mLbeat-1

268
Q

what does the average persons stroke volume reach during intense physical activity

A

130mLbeat-1

269
Q

in elite athletes what is the resting stroke volume

A

averages 110mLbeat-1

270
Q

what can elite athletes (cross country skiers) increase their stroke volume to at peak exercise

A

200mLbeat-1

271
Q

what factors have positive effects controlling cardiac output (Q) at rest and during exercise

A

parasympathetic (negative effect)

sympathetic

venous return

end diastolic volume

heart rate

stroke volume

272
Q

what does the cardiac output reflect

A

the functional capacity of the cardiovascular system

273
Q

what is cardiac output at rest for males

A

5L
average HR of 70beats.min and
average SVof 71.4mL

274
Q

what is cardiac output at rest for women

A

4L
average HR of 70beats.min
and
average SV of 50-60mL

275
Q

what do heart rates in healthy endurance athletes generally average at rest

A

50beats.min

276
Q

what is the average resting stroke volume in healthy endurance individuals

A

100mL

277
Q

what are some of the factors that explain why endurance athletes have a large stroke volume and low heart rate

A

increased vagal tone and decreased sympathetic drive both of which slow the heart

increased blood volume myocardial contractility and compliance of the left ventricle all of which augment the hearts stroke volume

278
Q

cardiac output increases rapidly during the transition from rest to steady rate exercise and then rises gradually until it plateaus when

A

blood flow meets the exercise metabolic requirements

279
Q

the endurance athlete achieves a large maximal cardiac output solely through a

A

large stroke volume

280
Q

enhancing stroke volume by….

A

diastolic filling versus systolic emptying

281
Q

what are the mechanisms that increase the hearts stroke volume during exercise

A

1) enhanced cardiac filling in diastole followed by a more forceful systolic contraction
2) greater systolic emptying- normal ventricular filling with a subsequent forceful ejection and emptying during systole
3) training adaptations that expand blood volume and reduce resistance to blood flow in peripheral tissues

282
Q

the stroke volume is affected by changes in ___,_____ and ____

A

preload
afterload
inotropy (contractility)

283
Q

in normal hearts the SV is not strongly influenced by afterload. Is this the same for failing hearts

A

no, the SV is highly sensitive to afterload changes

284
Q

what is the stroke volume equation

A

SV= end diastolic volume - end systolic volume

ie) volume when filled with blood - volume after contraction

285
Q

what factors affect the end diastolic volume (volume when filled with blood)

A

size of the heart
filling pressure
compliance of the LV (left ventricle)

286
Q

what factors affect the end systolic volume (volume after contraction)

A

afterload

LV contractile force

287
Q

exercise does what to the stroke volume

A

increase frank starling mechanism (contraction strength)

increase venous return (PRELOAD) and filling pressure
- end diastolic volume

decrease in afterload due to vasodilation (mean arterial pressure!)

288
Q

enhanced diastolic filling leads to

A

stronger contractions

289
Q

any factor that increases venous return or slows the heart produces greater ______ during the cardiac cycles diastolic phase

A

preload

290
Q

an increase in end diastolic volume stretches ___ fibers and initiates a powerful ___

A

myocardial
ejection stroke during contraction
this ejects normal SV plus additional blood that entered the ventricles in diastole

291
Q

the frank starling law of the heart states that the

A

force of contraction of the cardiac muscle remain s proportional to its initial resting length

292
Q

exercise training further improves what that contributes to the larger stroke volumes observed in athletes

A

ca2+ sensitivity of the contractile proteins

293
Q

the increase of the left ventricle during diastole = what

A

increase stretch and increase calcium sensitivity of the myocardium = increase force of contraction

294
Q

the heart create pressure as it contracts that pressure leads to

A

influence the open/closing of valves which regulate blood flow through the chambers of the heart

295
Q

the left ventricle starts to fill with blood when the ___ valve opens

A

mitral (tricuspid)

296
Q

pre load is what

A

end diastolic volume

297
Q

increase preload leads to

A

increased SV and ejection fraction

MORE BLOOD IN VENTRICLE BEFORE CONTRACTION

298
Q

starlings law in simple terms

A

ventricle more stretched, more forceful, and more blood ejected

299
Q

after load (aortic pressure) opens at the same or different pressure then pre load

A

same

300
Q

greater systolic ejection occurs despite

A

increased resistance to blood flow in the arterial circuit from exercise induced elevation of systolic blood pressure

301
Q

enhanced systolic ejection occurs because

A

The ventricles always contain a functional residual blood volume

302
Q

catecholamine release in exercise enhanced ______ to augment stroke power and facilitate systolic emptying

A

myocardial contractile force

303
Q

the end systolic pressure volume relationship describes what

A

the maximal pressure that can be developed by the ventricle at any given LV volume

304
Q

the increase in contractility =

A

ventricle contracts more forcefully

it changes neither preload nor afterload
increase SV and EJ
DECREASE end systolic volume

305
Q

training adaptations that expand blood volume and reduce resistance to blood flow in peripheral tissues which is

A

redistribution of blood to working tissues

neural and hormonal (sympathetic and parasympathetic)

long term adaptation in blood volume
- endurance trained larger plasma volume and more RBCs

306
Q

what is cardiovascular drift

A

describes the gradual time dependent downward drift in several cardiovascular responses, most notably stroke volume with concomitant heart rate increase, during prolonged steady rate exercise

307
Q

what does cardiovascular drift affect

A

decrease in volume return during prolonged exercise at submaximal effort

progressive decrease in SV
progressive increase in HR

therefore Q maintained over time

308
Q

submaximal exercise for more then 15 mins decreases plasma volume which ______

A

decreases stroke volume

309
Q

was does a decrease in tissue O2 cause for the vessels

A

a potent vasodilator stimulus

310
Q

what causes local dilation

A

increase blood flow temperature CO2 K NO Mg acidity and adenosine

311
Q

at rest the myocardium uses about ____% of the oxygen in the blood flowing through the coronary circulation

A

75%

312
Q

during exercise how much does coronary circulation increase

A

four-fivefold increase

313
Q

cerebral blood flow increases during exercise by about ____% compared with resting flow

A

25-30%

314
Q

arterial blood carries ____mL of oxygen per liter

A

200

315
Q

if resting cardiac output each min equals 5L potentially how much mL of oxygen will become available to the body

A

1000mL

316
Q

the resting oxygen consumption typically averages 250-300mLmin allowing ___mL of oxygen to return to the heart unused

A

750mL

317
Q

the extra oxygen circulating above the resting requirement represents what

A

oxygen in reserve

318
Q

a low maximal oxygen consumption corresponds with what

A

a low maximum cardiac output

319
Q

a 5-6L increase in blood flow accompanies each 1Lincrease in oxygen consumption above resting value; this relationship remains essentially

A

unchanged regardless of exercise mode

320
Q

exercise O2 consumption increases by what 2 mechanisms

A

increased cardiac output

greater usage of O2 by metabolically active tissue (greater a-v O2 difference)

321
Q

VO2 = Q x a-v O2 difference which means

A

cardiorespiratory fitness = O2 transport x O2 use

322
Q

red blood cells in the circulation sense local tissue ___ through their degree of deoxygenation

A

hypoxia

323
Q

a-v O2 difference between rest and exercise

A

rest

  • 20mL of O2 in each dL of arterial blood (200 ml of O2 per L)
  • at rest only 5mL of O2 is extracted per dL

exercise

  • 20mL of O2 in each dL of arterial blood
  • during maximal exercise only 16 to 18 mL of O2 is extracted per dL
324
Q

O2 difference during exercise increases in arterial O2 capacity due to

A

increase in capillary hydrostatic pressure

osmotic pressure that draws fluid from plasma into tissue spaces

325
Q

arms vs legs vo2

A

arms seems to have a higher oxygen consumption

326
Q

cardiovascular adaptations include

A

increase ejection
increase contractility
increased blood volume

327
Q

do athletes have bigger hearts

A

yes (left ventricular mass)

Exercise Physiology (13 decks)

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