Chapter 13 Flashcards

1
Q

The heart contains

A

blood vessels and blood

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2
Q

What substances does the heart transport

A
  • Oxygen and nutrients to cells
  • Wastes from cells to liver and kidneys
  • Hormones, immune cells, and clotting proteins to specific target cells
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3
Q

Label heart diagram

A
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4
Q

heart-> _____-> ____-> ____-> ____-> veins

A

arteries; arterioles; capillaries; venules

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5
Q

Arteries

A

large, branching vessels taking blood away from the heart

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6
Q

Arterioles

A

small branching vessels with high resistance

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7
Q

Capillaries

A

site of exchange between blood and tissue

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8
Q

Venules

A

small converging vessels

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9
Q

Veins

A

relatively large converging vessels that conduct blood to the heart

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10
Q

Pulmonary circuit

A
  • Supplied by right heart
  • Blood vessels from heart to lungs, and from lungs to heart
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11
Q

Systemic circuit

A
  • Supplied by left heart
  • Blood vessels from heart to systemic tissues, and from tissues to heart
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12
Q

how does oxygenation of blood occur?

A
  • Exchange between blood and tissue occurs in capillaries
  • Pulmonary capillaries
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13
Q

Blood entering lungs =

A

deoxygenated blood

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14
Q

Blood leaving lungs =

A

oxygenated blood

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15
Q

Blood entering tissues =

A

oxygenated blood

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16
Q

O2 diffuses from

A

blood to tissues

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17
Q

Blood leaving tissues =

A

deoxygenated blood

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18
Q

Cardiovascular system is a ____ system

A

closed

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19
Q

Path of blood flow

A

Left ventricle->aorta-> systemic circuit- >vena cavae- >right atrium- >right ventricle- >pulmonary artery-> pulmonary circuit- >pulmonary veins ->left atrium - >left ventricle

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20
Q

Coronary circulation

A
  • Parallel with other organs in the systemic circuit
  • Blood in chambers does not supply nutrients to cardiac cells
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21
Q

Heart has its own set of

A

capillaries

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22
Q

Heart capillaries are supplied by

A

coronary arteries (left and right) that arise from the aorta

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23
Q

The heart is located in what cavity

A

thoracic

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24
Q

What separates the abdominal cavity from the thoracic

A

diaphragm

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25
Q

Pericardium

A
  • Membranous sac surrounding the heart
  • Lubricates the heart and decreases friction
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26
Q

Pericarditis

A

inflammation of pericardium

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27
Q

label heart and lungs diagram

A
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28
Q

Three layers of the heart wall

A
  • Epicardium (outer)
    *External membrane
  • Myocardium (middle)
    *Cardiac muscle
  • Endothelium (inner)
    *Layer of endothelial cells
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29
Q

Pressure within chambers of the heart varies with

A

heartbeat cycle

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30
Q

Normal direction of flow

A

Atria to ventricles
Ventricles to arteries

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31
Q

What do valves prevent

A

backward flow of blood

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32
Q

All valves open ______based on pressure gradient

A

passively

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33
Q

Right AV valve =

A

tricuspid valve

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34
Q

Left AV valve =____ =____

A

bicuspid valve = mitral valve

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35
Q

function of Papillary muscles and chordae tendinae

A

Keep AV valves from everting

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36
Q

Semilunar valves

A

Aortic valve
Pulmonary valve

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37
Q

Autorhythmicity

A

the ability to generate own rhythm

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38
Q

Autorhythmic cells provide what

A

pathway for spreading excitation through the heart

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39
Q

Pacemaker cells

A
  • Spontaneously depolarizing membrane potentials generate action potentials
  • Coordinate and provide rhythm to heartbeat
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40
Q

Conduction fibers

A

Rapidly conduct action potentials initiated by pacemaker cells to myocardium

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41
Q

Pacemaker cells of the myocardium

A
  • Sinoatrial node (Pacemaker of the heart)
  • Atrioventricular node
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42
Q

Conduction fibers of the myocardium

A
  • Internodal pathways
  • Bundle of His
  • Purkinje fibers
43
Q

Know the firing rates of Autorhythmic cells

A
44
Q

Cardiac cells are linked by

A

gap junctions

45
Q

Fastest cells = _____ = ______

A

pacemaker; set rate for rest of heart

46
Q

Atria contract, then ____ contract

A

ventricles

47
Q

Intercalated disks

A
  • Junctions between adjacent myocardial cells
  • Desmosomes to resist mechanical stress
  • Gap junctions for electrical coupling
48
Q

Initiation and conduction of an impulse

A
  1. AP initiated in SA node; signals spread through atrial muscle via interatrial pathways
  2. Signal travels to AV node via internodal pathway; AV nodal delay
  3. Atrioventricular bundle (bundle of His)
  4. Splits into left and right bundle branches
  5. Purkinje fibers
49
Q

label heart conduction diagrams

A
50
Q

Ionic Basis of Electrical Activity in the Heart

A

Spontaneous depolarizations caused by closing K+channels and opening two types of channels

51
Q

Depolarizing to threshold consists of

A
  • Open fast Ca 2+ channels—action potential
  • cell with a less negative charge than the outside (+)
52
Q

Repolarization of the heart

A

Open K+ channels
- return to a negative value

53
Q

Five phases of electrical activity in cardiac contractile cells

A

Phase 0: increased permeability to Na+
Phase 1: decreased permeability to Na+
Phase 2: increased permeability to Ca2+, decreased permeability to K+
Phase 3: increased permeability to K+ , decreased permeability to Ca2+
Phase 4: resting membrane potential

54
Q

look at table 13.2

A
55
Q

properties of excitation-contraction coupling in cardiac contractile cells: skeletal

A
  • similar to skeletal muscle
  • T tubules
  • Sarcoplasmic reticulum Ca2+
  • Troponin-tropomyosin regulation
56
Q

properties of excitation-contraction coupling in cardiac contractile cells: smooth muscle

A

Gap junctions
Extracellular Ca2+

57
Q

First three steps of excitation-contraction coupling:

A
  1. Depolarization of cardiac contractile cell to threshold via gap junction
  2. Opening of calcium channels in plasma membrane
  3. AP travels down T tubules
58
Q

Steps 4-7 of excitation-contraction coupling

A
  1. Calcium is released from sarcoplasmic reticulum
  2. Calcium binds to troponin, causing a shift in tropomyosin
  3. Binding sites for myosin on actin are exposed
  4. Crossbridge cycle occurs
59
Q

Relaxation of cardiac muscle

A
  • Removes calcium from cytosol
  • Ca2+ ATPase in sarcoplasmic reticulum
  • Ca 2+ATPase in plasma membrane
  • Na+ -Ca2+ exchanger in plasma membrane
  • Troponin and tropomyosin return to their positions covering myosin-binding sites on actin
60
Q

Electrocardiogram

A
  • Can be recorded from electrodes on the skin
  • Noninvasive technique
  • Used to test for clinical abnormalities related to conduction of electrical signals in the heart
61
Q

Distance and amplitude of spread depend on two factors:

A

Size of potentials
Synchronicity of potentials from other cells

62
Q

P wave:

A

atrial depolarization

63
Q

QRS complex

A

ventricular depolarization and atrial repolarization

64
Q

T wave

A

ventricular repolarization

65
Q

PQ segment

A

AV nodal delay

66
Q

QT segmant

A

ventricular systole

67
Q

QT interval

A

ventricular diastole

68
Q

First-degree heart block

A
  • Slowed/diminished conduction through AV node occurs in varying degrees
  • Increases PQ segment duration
  • Increases delay between atrial and ventricular contraction
69
Q

Second-degree heart block

A
  • Slowed, sometimes stopped conduction through AV node
  • Lose 1-to-1 relationship between P wave and QRS complex
  • Lose 1-to-1 relationship between atrial and ventricular contraction
70
Q

Third-degree heart block

A
  • Loss of conduction through the AV node
  • P wave becomes independent of QRS
  • Atrial and ventricular contractions are independent
71
Q

Extra contraction

A
  • Results in an extra systole
  • Premature atrial contraction (PAC), followed by an extra ventricular contraction
72
Q

Ventricular fibrillation

A
  • Loss of coordination of electrical activity of heart
  • Death can ensue within minutes unless corrected
73
Q

Cardiac Cycle

A
  • Events associated with the flow of blood through the heart during a single complete heartbeat
  • Two main periods of cardiac cycle
74
Q

systole

A

ventricle contraction
- Aortic valve opens
- Pressure rises rapidly with ejection
- Highest point = systolic pressure
- Aortic valve closes
- Backflow of blood causes slight increase—dicrotic notch

75
Q

diastole

A

ventricle relaxation
- Aortic valve closes
- Blood is still leaving aorta, so pressure falls
- Lowest point = diastolic pressure

76
Q

Phases of Cardiac Cycle

A
  1. ventricular filling
  2. Isovolumetric ventricular contraction
  3. Ventricular ejection
  4. Isovolumetric ventricular relaxation
77
Q

What occurs during ventricular filling

A
  • Middle of ventricular diastole
  • Venous return
  • AV valve opens
  • Blood moves from atria to ventricle
  • Pulmonary and aortic valves are closed
  • Passive until atrium contracts
78
Q

What occurs during Isovolumetric ventricular contraction

A
  • Start of systole
  • Ventricle contracts—increases pressure
  • AV and semilunar valves closed
  • No blood entering or exiting ventricle
79
Q

What occurs during Ventricular ejection

A
  • Remainder of systole
  • Pressure in ventricles > pressure in arteries
  • Semilunar valves open
  • Ventricular pressure < aortic pressure
  • Semilunar valves close
80
Q

What occurs during Isovolumetric ventricular relaxation

A
  • Onset of diastole
  • Ventricle relaxes—decreases pressure
  • AV and semilunar valves closed
  • No blood entering or exiting ventricle
81
Q

Atrial and Ventricular Pressure : Phase 1

A
  • Atrial pressure rises slowly with filling of blood
  • Ventricular pressure is low
  • Small rise in VP at end due to atrial contraction
82
Q

Atrial and Ventricular Pressure: Phase 2

A
  • Rapid rise in ventricular pressure
  • Atrial pressure falls
  • Phase 3
  • Ventricular pressure falls
  • Atrial pressure falls further until late systole
83
Q

Aorta (and large arteries)

A
  • Pressure reservoir
  • Stores energy during systole as walls expand
  • Releases energy during diastole as walls recoil inward
  • Aortic pressure maintains blood flow through the entire cardiac cycle
84
Q

EDV

A
  • end-diastolic volume
  • Volume of blood in ventricle at the end of diastole
85
Q

ESV

A
  • end-systolic volume
  • Volume of blood in ventricle at the end of systole
86
Q

SV

A

stroke volume
Volume of blood ejected from ventricle each cycle
SV = EDV – ESV

87
Q

Ejection fraction (EF)

A
  • fraction of end-diastolic volume ejected during a heartbeat
  • EF = stroke volume/end diastolic volume
  • EF = 70 mL/130 mL = 0.54
88
Q

First heart sound

A
  • Soft “lubb”
  • AV valves close simultaneously
89
Q

Second heart sound

A
  • Louder “dupp”
  • Semilunar valves close simultaneously
90
Q

Cardiac output (CO)

A

SVxHR

91
Q

Extrinsic

A

neural and hormonal

92
Q

Intrinsic

A

autoregulation

93
Q

Heart rate

A
  • determined by SA node firing frequency
  • SA node intrinsic firing rate = 100/min
94
Q

during rest what system dominates

A

parasympathetic system dominates; HR = 75

95
Q

During excitement what system dominates

A

sympathetic system takes over; HR increases

96
Q

Epinephrine

A
  • Same effect as sympathetic nervous system
  • Increases action potential frequency at SA node
  • Increases velocity of action potential conduction in muscle fibers
97
Q

Activity of sympathetic neurons projecting to SA node does what?

A

raises HR

98
Q

Activity of parasympathetic neurons projecting to SA node does what?

A

lowers HR

99
Q

Levels of circulating epinephrine

A

raises HR

100
Q

Epinephrine binds to

A

B1 adrenergic receptors

101
Q

Thyroid hormones, insulin, and glucagon increase

A

force of contraction

102
Q

Starling’s law

A
  • Increased EDV stretches muscle fibers
  • Fibers closer to optimal length
  • Optimal length → greater strength of contraction
  • Result → increased SV
103
Q

Factors affecting end-diastolic volume

A
  • End-diastolic pressure =preload
    *Filling time
    *Atrial pressure
    *Central venous pressure
  • Afterload = pressure in aorta during ejection