Physio Ch 09 Flashcards

1
Q

pumps blood through the lungs

A

right heart

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2
Q

pumps blood through the peripheral organs

A

left heart

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3
Q

pulsatile two-chamber pump

A

heart

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4
Q

weak primer pump for the ventricle, helping to move blood into the ventricle

A

Atrium

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5
Q

Ventricles supply the main pumping force that propels the blood either

A
  1. through the pulmonary circulation by the right ventricle
  2. through peripheral circulation by the left ventricle
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6
Q

continuing succession of heart contractions transmitting action potentials throughout the cardiac muscle to cause the heart’s rhythmical beat

A

cardiac rhythm

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7
Q

Three major types of cardiac muscle

A
  1. atrial muscle
  2. ventricular muscle
  3. specialized excitatory and conductive muscle fibers
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8
Q

provide excitatory system that controls the
rhythmical beating of the heart

A

excitatory and conductive
fibers

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9
Q

dark areas crossing the cardiac muscle fibers

A

intercalated discs

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10
Q

cell membranes that separate individual cardiac muscle cells from one another

A

intercalated discs

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11
Q

At each intercalated disc the cell membranes fuse with one another and form this structure that allow rapid diffusion of ions

A

gap junctions

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12
Q

causes ventricular contraction to last as much as 15 times as long in cardiac muscle as in skeletal muscle

A

plateau

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13
Q

.

A

.

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14
Q

velocity of conduction in the specialized heart conductive system

A

4 m/sec

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15
Q

interval time which a normal cardiac impulse cannot reexcite an already excited area of cardiac muscle

A

refractory period

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16
Q

normal refractory period of the ventricle

A

0.25 to 0.30 secs

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17
Q

period which muscle is more difficult than normal to excite but can be excited by very strong excitatory signal

A

relative refractory period

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18
Q

refractory period of atrial muscle

A

0.15 seconds

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19
Q

refractory period of ventricular muscles

A

0.25 to 0.30 seconds

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20
Q

mechanism by which the action potential causes the myofibrils of muscle to contract

A

excitation-contraction coupling

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21
Q

velocity of conduction of the excitatory action potential signal along both atrial and ventricular muscle fibers

A

0.3 - 0.5 m/sec or 1/250 in large nerve fibers or 1/10 in skeletal muscle fibers

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22
Q

calcium entering the cell activates these channels to release calcium from sarcoplasmic reticulum

A

calcium release channels, ryanodine receptor channels

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23
Q

Inside is a large quantity of mucopolysaccharides that are electronegatively charged and bind an abundant store of calcium ions

A

T tubules

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24
Q

Transport of calcium back into
the sarcoplasmic reticulum is achieved with the help of a

A

calcium-ATPase pump

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25
Q

cardiac events that occur from the beginning of one heartbeat to the beginning of the next are called

A

cardiac cycle

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26
Q

Each cardiac cycle is initiated by spontaneous generation of an action potential in the?

A

sinus node

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27
Q

act as primer pumps for the ventricles

A

atria

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28
Q

period of relaxation during which the heart fills with blood

A

diastole

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29
Q

total duration of the cardiac cycle, including systole and diastole, is the reciprocal of the?

A

heart rate

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30
Q

At a normal heart rate of 72 beats/min, systole comprises about ____ of the entire cardiac cycle.

A

0.4

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31
Q

At three times the normal heart rate, systole is about ____ of the entire cardiac cycle.

A

0.65

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32
Q

a wave in the electrocardiogram caused by spread of depolarization through the atria

A

P wave

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33
Q

How many seconds will the QRS waves appear after the onset of the P wave?

A

0.16 sec

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34
Q

appear as a result of electrical depolarization
of the ventricles

A

QRS waves

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35
Q

this complex begins slightly before the onset of ventricular systole

A

QRS

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36
Q

represents the stage of repolarization of the ventricles when the ventricular muscle
fibers begin to relax

A

ventricular T wave

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37
Q

a wave is caused by

A

atrial contraction

38
Q

During pressure change, right atrial pressure increases ______ during atrial
contraction, while left atrial pressure increases _____

A

4 to 6 mm Hg; 7 to
8 mm Hg

39
Q

c wave occurs when the ventricles begin to?

A

contract

40
Q

pressure change wave caused partly by slight backflow of blood into the atria
mainly by bulging of the A-V valves backward toward the atria due to
increasing pressure in the ventricles

A

c wave

41
Q

pressure change wave which occurs toward the end of ventricular contraction that results from slow flow of blood into the atria from the veins

A

v wave

42
Q

It is the filling of ventricles due to pressure accumulated in the atrium during ventricular systole which pushed the AV valves open

A

period of rapid filling of the ventricles

43
Q

during this period, contraction is occurring in the ventricles, but there is no emptyingq

A

Period of isovolumic (isometric) contraction

44
Q

the tension is increasing in the muscle but little or no shortening of the muscle fibers is occurring

A

isovolumic or isometric contraction

45
Q

How many % of blood is poured out of the ventricles on the first third or period of rapid ejection?

A

70%

46
Q

This the remaining 30% of blood emptied at the ventricles during the next two thirds of ejection

A

period of slow ejection

47
Q

When ventricular relaxation occurs after the end of systole, this pressure decreases rapidly

A

intraventricular pressures

48
Q

During this period, the intraventricular pressures decrease rapidly back to their low diastolic levels

A

isovolumic or isometric relaxation

49
Q

During diastole, normal filling of the ventricles increases the volume of each ventricle to how many ml

A

110 to 120 ml

50
Q

as the ventricles empty during systole, the volume decreases about 70 ml, which is
called …..

A

stroke volume output

51
Q

normal filling of the ventricles which increases the volume of each ventricle, called as?

A

end diastolic volume

52
Q

remaining volume in each ventricle after systole, about 40 to 50 ml, is called

A

end systolic volume

53
Q

It is the fraction of the end-diastolic volume that is ejected

A

ejection fraction

54
Q

When the heart contracts strongly, the end-systolic volume can be decreased to as little as

A

10 to 20 ml

55
Q

In a healthy heart, when large amounts of blood flow into the ventricles during diastole, the ventricular end-diastolic volumes can
become as great as

A

150 to 180 ml

56
Q

prevent backflow of blood from the
ventricles to the atria during systole

A

AV valves

57
Q

prevent backflow from the aorta and pulmonary arteries into the ventricles during diastole

A

semilunar valves

58
Q

occurs in the aortic pressure curve
when the aortic valve closes

A

incisura

59
Q

pull the vanes of the valves
inward toward the ventricles to prevent their bulging too far backward toward the atria during ventricular contraction

A

papillary muscle

60
Q

What is the diastolic pressure of the aortic pressure before the ventricle contracts again?

A

80 mm Hg

61
Q

Sound of closure of the A-V valves with its low vibration and relatively low lasting

A

first heart sound

62
Q

aortic and pulmonary valves close at the end
of systole bearing a rapid snap because the valves close rapidly

A

second heart sound

63
Q

amount of energy that the heart converts to work during each heartbeat while pumping blood into the arteries

A

stroke work output

64
Q

total amount of energy converted to work in 1 minute

A

minute work output

65
Q

Two forms of work output of the heart

A
  1. volume-pressure work or external work
  2. kinetic energy of blood flow
66
Q

major proportion is used to move the blood from the low-pressure veins to the high-pressure arteries

A

volume-pressure work

67
Q

form of output which minor proportion of the energy is used to accelerate the blood to its
velocity of ejection through the aortic and pulmonary valves

A

kinetic energy of blood flow

68
Q

determined by filling the heart with progressively greater volumes of blood

A

diastolic pressure curve

69
Q

It is the measuring of the diastolic pressure immediately before ventricular contraction occurs

A

end diastolic pressure

70
Q

determined by recording the systolic pressure achieved during ventricular contraction at each volume of filling

A

systolic pressure curve

71
Q

What is the maximum systolic pressure for the normal left ventricle

A

250-300 mm Hg

72
Q

What is the maximum systolic pressure of a normal right ventricle?

A

60-80 mm Hg

73
Q

Phase I or Period of filling in the volume-pressure diagram begins at a ventricular volume of about ____ and diastolic pressure of ____ ?

A

50 ml and a diastolic pressure of 2 to 3 mm Hg

74
Q

The amount of blood that remains in the ventricle after the previous heartbeat, 50 ml, is called

A

end systolic volum

75
Q

Phase of cardiac cycle wherein the pressure inside the ventricle increases to equal the pressure in the aorta, at a pressure value of about 80 mm Hg

A

Period of isovolumic contraction

76
Q

the LOAD considered to be the end-diastolic pressure when the ventricle has become filled

A

preload

77
Q

what type of load describes by the pressure in the aorta leading from the ventricle

A

afterload

78
Q

Enumerate the sources of energy of heart muscles with their respective %

A
  1. Oxidative metabolism of fatty acids - 70-90%
  2. Lactate and glucose - 10-30%
79
Q

represents additional work that could be accomplished by contraction of the ventricle if the ventricle should empty completely all
the blood in its chamber with each contraction

A

potential energy

80
Q

Basic means by which the volume pumped
by the heart is regulated (2)

A

(1) intrinsic cardiac regulation of pumping in response to changes in volume of
blood flowing into the heart
(2) control of heart rate and strength of heart pumping by the autonomic nervous system

81
Q

During heart muscle contraction, most of the expended chemical energy is converted into ____ and a much smaller portion into _____-

A

heat; work output

82
Q

ratio of work output to total chemical energy
expenditure is called

A

efficiency of cardiac contraction or efficiency of the heart

83
Q

Maximum efficiency of the normal heart is between ……

A

20-25%

84
Q

In heart failure, maximum efficiency of the heart can decrease to as low as ____

A

5-10%

85
Q
A
86
Q

heart is composed of two syncytiums;

A

atrial syncytium and ventricular syncytium

87
Q

constitutes the walls of the two atria

A

atrial syncytium

88
Q

constitutes the walls of the two ventricles

A

ventricular syncytium

89
Q

a bundle of conductive fibers several millimeters of ventricular contraction. they are conducted only by way of a specialized conductive system

A

A-V bundle

90
Q

also called calcium-sodium channels

A

slow calcium channels

91
Q

the atria act as ___________ for the ventricles, and the ventricles in turn provide the major source of power for moving the blood through the body’s vascular system

A

primer pumps