CH. 9 Cardiac

Question 1

circlatory system

Answer 1

transport system of the body
three basic components: heart(pump), blood vessels(passageways), blood(transport medium)

Question 2

pulmonary circulation

Answer 2

blood travels between heart and lungs

Question 3

systemic circulation

Answer 3

blood flow between the heart and all body systems

Question 4

Atria

Answer 4

upper chambers (recieve blood)

Question 6

Ventricles

Answer 6

lower chambers (pump blood)

Question 7

Heart valves

Answer 7

ensure blood flows in correct direction
open and close passivley becasue of pressure differences

Question 8

Atrioventricular (AV) valves

Answer 8

between the atria and ventricles on the left and right sides of the heart
blood flows from the atria into the ventricles, valves prevent backflow

Question 9

Three distinct layers of the heart wall

Answer 9

endothelium
myocardium
epicardium

Question 10

endothelium

Answer 10

thin epithelial tissue lining the entire circulatory system

Question 11

myocardium

Answer 11

thick layer of cardiac muscle; constitutes the bulk of the heart wall

Question 12

epicardium

Answer 12

a thin external layer covering the heart

Question 13

intercalated discs

Answer 13

specialized structures where adjacent cardiac muscle cells are joined end-to-end

Question 14

Syncytium

Answer 14

the cells contract in unison to produce the force needed to eject the encolsed blood

Question 15

Organization of cardiac muscle fibers

Answer 15

a. bundles of cardiac muscles are arranged spirally around the ventricle
b. cardiac muscle fibers branch and are interconnected by intercalated discs
c. plasma membranes of adjacent cardiac muscle fibers

Question 16

Automaticity/Autorhythmicity

Answer 16

the heart generates its own action potentials

Question 17

2 types of cardiac muscle cells

Answer 17

contractile cells
autorhthmic cells (pacemaker/noncontractile

Question 18

Contractile Cells

Answer 18

-99% of the cardiac muscle cells
-do the mechanical work of pumping
-they do not initiate own action potentials

Question 19

Autorhythmic cells

Answer 19

-initiate and conduct the action potentials
-responsible for contraction of the contractile cells
-the action potential they initaiate spreads through the heart to trigger the heart beating without nervous stimulation

Question 20

Pacemaker potential

Answer 20

1st half: increased inward Na+, decreased outward K+
2nd half: increased inward Ca2+ movement
Rising phase: opening Ca2+ channels
Falling Phase: opening k+ channels

Question 21

Where are the autorhythmic cells

Answer 21

-Sinoatrial node: right atrial wall near vena cava
-Atrioventricular node: in right wall
-Bundle of His: originates at AV node, split and travels down the ventricles
-Purkinje fibers: spread from Bundle of His throughout the myocardium

Question 22

Electrocardiogram (ECG)

Answer 22

record of the spread of electrical activity through the heart
represents comparisons in voltage detected at two points on the body surface (not actual action potential)

Question 23

drop of blood through a complete circuit of the circulatory system

Answer 23

right atrium, right ventricle, pulmonary arteries, lungs, pulmonary veins, left atrium, left ventricle, aorta, systemic arterial circulation, capillaries for exchange, small veins, large veins, superior and inferior vena cava, right atrium

Question 24

why is the SA node the pacemaker of the heart

Answer 24

it has the fastest rate of autorhythmicity, its pace drives the rest of the heart

Question 25

name the four heart valves+location

Answer 25

-atrioventricular (AV) - [r: tricuspid l:bicuspid] between the atria and ventricles on both sides of the heart -Semilunar valves - [r: pulmonary l:aortic] between the ventricle on each side and the major artery that leaves each ventricle

Question 26

what do the diff valve types do

Answer 26

atrioventricular - prevent eversion through chordar tendae connected to papillary muscle semilunar- prevent eversion bc their edges fit together in deep, leak proof seams

Question 27

describe the spread of cardiac excitation

Answer 27

SA node -> AV node (where av nodal delay happens) -> Bundle of His -> purkinje fibers in ventricular walls

Question 28

what is the significance of the AV node delay

Answer 28

it is significant because the delay allows for the atria to contract and completley fill the ventricles before the ventricles begin contraction so the ventricles have max blood

Question 29

why is tetanus of cardiac muscle impossible

Answer 29

it is impossible in cardiac muscle because of the significantly long refractory period

Question 30

what electrical event does each component of the ECG represents

Answer 30

-p wave: depolarization across atria -QRS complex: depolarization across the ventricles -T wave: ventricular repolarization

Question 31

describe a stenotic valve

Answer 31

stiff, narrow valve that does not open completley. blood needs to be forced through the narrow opening at higher pressures

Question 32

describe an insufficent valve

Answer 32

does not close completely, blood might flow backward through the valve (regurgitation) based on severity

Question 33

ejection fraction

Answer 33

the proportion of blood ejected out of the ventricle during each heartbeat, is equal to the stroke volume divided by end distilic volume

Question 34

cardiac reserve

Answer 34

the difference in cardiac output at rest and the maximal amount of blood the heart can pump in one minute

Question 35

end distolic/ end systolic volume

Answer 35

end distolic volume: amount of blood in the ventricle at the end of distole (before it contracts) end systolic volume: amount of blood in the ventricle at the ned of systole (after it contracts)

Question 36

stroke volume

Answer 36

the amount of blood pumped out of each ventricle per contraction

Question 37

heart rate

Answer 37

the numberof beats per minute

Question 38

cardiac output

Answer 38

the volume of blood pumped by each ventricle per minute

Question 39

describe the autonomic nervous system control of heart rate

Answer 39

sympathetic nervous system increases heart rate parasympathertic system decreases heart rate

Question 40

what are the pathalogical chnages and consenquences of coronary artery disease

Answer 40

it is a pathalogical changes in the coronary arteries and can lead to vascular spasms, formation of atherosclerotic plaques and blood clots. this can lead to decreased blood flow in the vessels supplying cardiac tissue and can lead to tissue death (myocardial infarction or heart attack)

Question 41

sources of cholesterol

Answer 41

dietary intake and manufacture by cells (especially liver cells

Question 42

transport of cholesterol

Answer 42

cholesterol carried by LDL complexes are "bad cholesterol" bc its transoirted to cells including those lining blood vessel walls cholerterol carried by HDL complexes are "good cholesteral" because GDL removes cholesterol from cells and transports it back to the liver for elimination

Question 43

elimination of cholesterol

Answer 43

cholesterol goes to liver for elimination and then the liver adds excess cholesterol to bile where it is secreted into the digestive and eliminated from the body in feces.