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APHY 164 > AnP Chapter 15 (LO6) > Flashcards

AnP Chapter 15 (LO6) Flashcards

1
Q

The human heart beats about —— times in one day, about ——— times in a year and more than—– times during an average lifetime

A

The human heart beats about 100,000 times in one day, about 35 million times in a year and more than 2.5 billion times during an average lifetime

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2
Q

Mediastinum

A

a space between the lungs and beneath the sternum

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3
Q

Base

A

where are the great vessels enter and leave the heart

the produce part of the heart at the upper right

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4
Q

apex

A

the point of maximum impulse where the strongest be can be felt or heard

The pointed end at the lower left

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5
Q

Key structures of the heart

A

include the pericardium, the heart wall, the chambers, and the valves

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6
Q

Pericardium

A

A double walled sac that surrounds the heart

Anchored by ligaments and tissues to surrounding structures

Has two layers the fibrous pericardium in the Serous pericardium

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7
Q

fibrous pericardium

A

loose fitting sack of strong connective tissue

the outer most layer

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8
Q

serous pericardium

A

consists of two layers

covers the hearts surface

It folds back on itself at the hearts base to form the parietal layer and visceral layer

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9
Q

Parietal layer

A

lions inside of the fibrous pericardium

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10
Q

Visceral layer

A

covers the hearts surface

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11
Q

Pericardial cavity

A

cavity contains a small amount of serous fluid which helps prevent friction is the heartbeats

Between the parietal layer and visceral layer

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12
Q

The heart wall

A

Consists of three layers

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13
Q

Endocardium

A

lines the heart chambers, covers the valves, and continues into the vessels

Very smooth which helps keep blood from clotting as it fills the hearts Chambers

it consists of a thin layer of squamous epithelial cells

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14
Q

Myocardium

A

composed of cardiac muscles, formed the middle where

it’s the thickest of the three layers and performs the work of the heart

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15
Q

Epicardium

A

consists of a thin layer of squamous epithelium cells, covers a hard surface ‘

Also known as the visceral layer of the serous pericardium

the epicardium is closely integrated with the myocardium

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16
Q

The heart contains four hollow chambers

A

the two upper chambers are called atria or atrium for singular

the two lower chambers are called ventricles

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17
Q

great vessels

A

several large vessels attached to the heart that transport blood to and from the heart

Includes the superior and inferior vena, pulmonary artery (which branches into a right and left pulmonary artery), four pulmonary veins (two for each lung) and the aorta

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18
Q

Atria

A

Serve primarily as reservoirs receiving blood from the body or lungs

Interatrial septum: a common wall of the myocardium that separates the right and left atria

Don’t have to generate much force because only moves blood a short distance

The walls of the atria not very thick

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19
Q

Ventricles

A

Service pumps receiving blood from the atria and then pumping it either to the lungs (right ventricle) or the body (left ventricle)

Interventricular septum separates the right and left ventricles

Generates more force than the atria because they pump blood rather than receive

The walls of the ventricles are thicker

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20
Q

heart valves

A

To ensure that blood moves in a forward direction the heart contains four valves

One between each atrium and it’s ventricle and another at the exit of each ventricle each valve is formed by two or three flats of tissue called cusps or leaflets

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21
Q

atrioventricular (AV) valves

A

regulate flow between the atria in the ventricles

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22
Q

The right AV valve

A

prevents backflow from the right ventricle to the right atrium

Also called the Tricuspid valve because it has three leaflets

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23
Q

The left AV valve

A

prevents backflow from the left ventricle to the left atrium

Commonly known as the mitral valve

Also known as the bicuspid valve because it has two leaflets

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24
Q

The semilunar valves

A

regulate flow between the ventricles in the great arteries there are two semi lunar valves: pulmonary and aortic

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25
Q

Pulmonary valve

A

prevents backflow from the pulmonary artery to the right ventricle

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26
Q

Aortic valve

A

prevents backflow from the aorta to the left ventricle

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27
Q

Skeleton of the heart

A

semi rigid fibrous connective tissue that in circles each valve

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28
Q

functions of skeleton of heart

A

Offer support for the heart,

keeps the valves from stretching,

acts as an insulating barrier between the atria in the ventricles preventing electrical impulses from reaching the ventricles other than through a normal conduction pathway

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29
Q

Where the sounds can be heard the loudest in heart

A
  1. Aortic area: second intercostal space, right sternal border
  2. Pulmonary valve: second intercostal space, left sternal border
  3. Tricuspid area: fourth (or fifth) intercostal space, left sternal border
  4. Mitral area: fifth intercostal space, left midclavicular line
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30
Q

Valvular insufficiency

A

a heart valve that fails to prevent the backflow of blood during contraction it’s called incompetent

Valvular insufficiency allows blood to leak backward or regurgitate into the chamber from which it was just pumped

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31
Q

Valvular stenosis

A

A stenotic valve that’s become narrowed such as from scar tissue

Force the heart to work harder causing it to strain

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32
Q

Heart mummur:

A

abnormal sound from turbulence as a result of the backflow of blood through an incompetent valve are the force of blood moving through a stenotic valve

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33
Q

Blood Flow through the Heart how it works

A
  1. The right atrium receives the auction needed blood returning from the body through the superior and inferior vena cavae
  2. Once the right atrium is full of contracts
    a) this forces the tricuspid valve open and blood flows into the right ventricle
    b) when the right ventricle is full the tricuspid valve snaps close to prevent blood from flowing backwards into the atria
  3. After filling the right ventricle contracts forcing the pulmonary valve open
    a) Blood is pumped into the right and left pulmonary arteries and onto the lungs
    b) After the right ventricle empties the pulmonary valve closes to prevent blood from flowing backwards into the ventricle
  4. After replenishing its supply of oxygen in the lungs the blood enters the pulmonary veins and returns to the heart through the left atrium
  5. When the left atrium is full it contracts
    a) this forces the mitral or bicuspid valve open and blood is pumped into the left ventricle
  6. When the left ventricle is for the mitral valve closes to prevent backflow
    a) The ventricles then contracts forcing the aortic valve to open allowing blood to flow into the aorta
    b) From there oxygenated blood is distributed to every organ in the body
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34
Q

Coronary Circulation

A

The heart muscle requires an abundant supply of oxygen and nutrients

Because of its high demand the heart has its own vascular system known as the coronary circulation

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35
Q

Coronary arteries

A

deliver oxygenated blood to the myocardium while cardiac veins collect the deoxygenated blood

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36
Q

Two main coronary arteries

A

arise from the descending aorta and serve as the principal routes for supplying blood to the myocardium

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37
Q

The right coronary artery supplies blood to:

A

the right atrium,

part of the left atrium,

most of the right ventricle,

the inferior part of the left ventricle

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38
Q

the left coronary artery supplies blood to

A

Left atrium

most of the left ventricle

most of the interventricular septum

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39
Q

After flowing through the capillaries in the myocardium the cardiac veins…

A

collect deoxygenated blood

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40
Q

Coronary sinus

A

a large transverse vein on the heart posterior which returns the blood to the right atrium

Post cardiac veins empty into it

41
Q

Coronary artery disease

A

results when the coronary arteries become blocked or narrow by a buildup of cholesterol and fatty deposits (atherosclerosis)

Any interruption in blood supply to the myocardium deprived the heart issues of oxygen (ischemia) causing pain and within minutes cell (nercrosis) death occurs

42
Q

Angina pectoris

A

sometimes interruption is temporary and a partially blocked vessel spasms or the heart demands more oxygen than the narrowed vessels can supply resulting in chest pain and ischemia

43
Q

Myocardial infarction

A

blood flow is completely blocked by a blood clot or fatty deposit resulting in death of myocardial cells in the area fed by the artery once the cells die they produce an area of necrosis

44
Q

Cardiac Conduction

A

Does not depend on stimulation by extrinsic nerves to contract

45
Q

pacemaker cells

A

specialize cells that generate action potentials to stimulate contraction a trait called automaticity

46
Q

rhythmicity

A

the heartbeats regularly

47
Q

Electrical impulse is generated by the heart follower very specific route to the myocardium shown here:

A
  1. Normal cardiac impulses arise in the sinoatrial (SA) node from its spot in the wall of the right atrium just below the opening of the superior vena cava
  2. An interatrial bundle of conducting fibers rapidly conduct impulses to the left atrium and both atria begin to contract
  3. The impulse travels along three internodal bundles to the atrioventricular (AV) node
    a) They are the impulse slows considerably to allow the atria time to contract completely in the ventricles to fill with blood
    b) The hard skeleton insulates the ventricles ensuring that only impulses passing through the AV node can enter
  4. After passing through the AV node the impulse picks up speed
    a) If then travels down the bundle of His also called the atrioventricular AV bundle
  5. The AV bundle soon branches into right and left bundle branches
  6. Purkinje fibers distribute the impulses to the muscle cells of both ventricles causing them to contract almost simultaneously
48
Q

Ectopic pacemakers

A

pacemakers other than the SA node

49
Q

The heart pacemakers and they’re firing rates when the heart is at rest are as follows:

SA node: fires at —- to — bpm
AV node: fires at — to — bpm
Purkinje fibers: fires at — to –bpm

A

SA node: fires at 60 to 80 bpm

AV node: has a firing rate of 40 to 60 bpm

Purkinje fibers: have a firing rate of 20 to 40 bpm

50
Q

Electrocardiogram

A

Cardiac impulses generate electrical currents that travel through the heart that are recorded

51
Q

Normal sinus rhythm

A

an ECG that appears normal meaning the impulse originates in the SA node

52
Q

Arrythmia

A

irregular heartbeat

53
Q

P wave

A

represents atrial depolarization

54
Q

Atrial depolarization

A

the transmission of electrical impulses from the SA node through the atria

It occurs right before the atria contract

55
Q

PR interval

A

represents the time it takes for cardiac impulse to travel from the atria to the ventricles

56
Q

QRS complex:

A

presents ventricular depolarization

57
Q

Ventricular depolarization

A

the spread of electrical impulses throughout the ventricles

58
Q

ST segment

A

presents the end of ventricular depolarization in the beginning of ventricular repolarization

59
Q

T wave:

A

represents ventricular repolarization

60
Q

Arrythmias

A

Result when part of the conduction pathway is injured or when part of the myocardium other than the SA node generates a beat

61
Q

Common cardiac arrhythmias

A

atrial flutter,

premature ventricular contractions

ventricular fibrillation

62
Q

atrial flutter

A

occurs when an ectopic focus in the atria fire is rapidly causing the atria to contract between 200 and 400 bpm

The AV node blocks impulses in excess of 180 bpm protecting the heart from life-threatening ventricular response

63
Q

Premature ventricular contractions PVCs

A

may occur as a single beat or inverse of several beats result from the firing of an ectopic focus in the ventricles

may indicate a serious underlying condition but benign causes include a lack of sleep, caffeine, or emotional stress

64
Q

Ventricular fibrillation

A

life-threatening emergency resulting from electrical signals arising from different regions of the myocardium, fibrillation causes the heart to quiver rather than contract

Fibrillating heart can’t pump blood and it must be defibrillated immediately

65
Q

Cardiac Cycle

A

The series of events that occur from the beginning of one heartbeat to the beginning of the next

66
Q

here’s what happens during 1 heart beat:

Passive ventricular filling

A

Returning venous blood has failed the atria causing their pressure to rise above that in the ventricles

The AV valves open and blood flows into the ventricles

The P wave appears on the ECG marking the end of atrial depolarization

67
Q

here’s what happens during 1 heart beat:

Atrial systole

A

The AV valves are open in the semilunar valves are closed

The atria contract to eject the remaining volume of blood

The ventricles are relaxed filling with blood

68
Q

here’s what happens during 1 heart beat:

Isovolumetric contraction

A

This is a brief period during which the ventricles are beginning to contract but the semi lunar valve’s haven’t opened yet

Iso: equal
volumetric: volume isovolumetric: something having same volume

The volume of blood in the ventricles remains constant but the pressure rises rapidly as the ventricles begin to contract

The R wave tears on the ECG

First heart sound S1 can be heard

69
Q

here’s what happens during 1 heart beat:

Ventricular ejection

A

the pressure in the ventricles exceeds the pressure in the pulmonary artery and aorta the semilunar valves open

Blood spots out of ventricle rapidly at first and then more slowly as the pressure drops

residual volume: the remaining blood the end of the ejection period that the ventricles don’t eject in the ventricles

The T wave occurs late in this phase beginning at the moment of peak ventricular pressure

70
Q

Isovolumetric ventricular relaxation

A

This is the period at the end of ventricular ejection before the AV valves opened but after the semilunar valves are closed to prevent blood from reentering the ventricles

Volume of blood in the ventricles remains unchanged but the pressure falls dramatically as the ventricles relax

T wave ends on the ECG

The second heart sound S2 can be heard as blood rebounds against the closed semilunar valves

71
Q

Cardiac output (CO)

A

refers to the amount of blood the heart pumps in 1 minute

To determine cardiac output multiplying the heart rate by the stroke volume SV (the amount of blood ejected with each heartbeat)

HR X SV = CO

CO increases with exercise but the average CO is 5 or 6 liters per minute

72
Q

Because cardiac output equals heart rate times stroke volume, the only two ways to affect cardiac output are:

A

Change the heart rate

Change the stroke volume

Keep in mind when HR increases SV decreases

73
Q

Bradycardia

Tachycardia

A

Bradycardia: a persistent pulse rate slower than 60 bpm

Tachycardia: a persistent resting heart rate greater than 100 bpm

74
Q

medulla effect on heart rate

A

The medulla in the brain detect changes in the body and sends messages to the sympathetic or parasympathetic nervous system to raise or lower heart rate

75
Q

how does the medulla affect the heart rate

A

1.Medulla in the brain contains a cardiac center

The cardiac center contains an acceleratory center and inhibitory center

76
Q

HEART RATE: Acceleratory center

A

Factors such as exercise and stress stimulate it

Acceleratory center sends out impulses via the sympathetic nervous system

77
Q

HEART RATE:inhibitory center

A

Factors such as a rise in blood pressure stimulate the inhibitory center

The inhibitory center sends signals via the parasympathetic nervous system

78
Q

HEART RATE: Sympathetic nervous system

A

sends impulses through cardiac nerves (which secrete norepinephrine) to the SA node, the AV node, and the myocardium

this accelerates the heart rate and increases the force of contractions

79
Q

HEART RATE: parasympathetic nervous system

A

Send signals via the vagus nerve (which secretes acetylcholine) to the SA and AV nodes which slows the heart rate

80
Q

Input to the cardiac center

A

The cardiac centre in the medulla receives input from multiple sources to initiate changes in the heart rate these include receptors in the muscles, joints, arteries, and brain stem

81
Q

Proprioceptors

A

in muscles and joints and signal the cardiac center of changes in physical activity

this allows the heart to increase output even before the muscles demand more blood flow

82
Q

Chemoreceptors

A

found in the aortic arch, carotid arteries and medulla

Detect increases in carbon dioxide, decreases in oxygen and decreases in pH

In response to sympathetic nervous system increases heart rate and stroke volume to circulate more oxygen

83
Q

Carotid body

A

a cluster of chemo receptors near the fork of the carotid artery

84
Q

Aortic body

A

a cluster of chemo receptors in the aorta

85
Q

Baroreceptors (pressoreceptors):

A

pressure sensors in the aorta an internal carotid arteries and detect changes in blood pressure

86
Q

stroke volume

A

Stroke volume is never 100% of the volume in the ventricles

Typically the ventricles eject 60% to 80% of their blood volume

87
Q

Ejection fraction

A

the percent of the volume that the ventricles eject

88
Q

Factors affecting stroke volume

A

preload, contractility and afterload

89
Q

Preload

A

The amount of tension, or stretch, in the ventricular muscle just before it contracts

The more blood entering the heart, the more the ventricle stretches

90
Q

Contractility

A

The force of which ventricular ejection occurs

how much the ventricle is stretched, the more blood return to the heart each minute, the more forcefully it will contract

91
Q

Afterload

A

The forces the heart must work against (as the pressure of the blood in the arteries) to eject its volume of blood

An increase in afterload such as high blood pressure opposes the ejection of blood from the ventricles which decreases stroke volume

92
Q

Inotropic agents

A

factors that affect contractility

93
Q

Positive inotropic agents

A

agents that increase contractility includes access excess calcium and epinephrine

94
Q

Negative inotropic agents

A

agents that decrease contractility includes a calcium deficiency as well as a potassium excess

95
Q

Chronotropic agents

A

factors that influence heart rate

96
Q

Positive Chronotropic agents

A

agents that increase heart rate include epinephrine and low levels of calcium

97
Q

Negative Chronotropic agents

A

agents that decrease heart rate include acetylcholine and excess levels of potassium

98
Q

Left Ventricular Failure

A

If the left ventricle fails it falls behind and injecting all of the blood it receives from the lungs

Consequently blood backs up in the lungs

This causes:
shortness of breath
a buildup of fluid in the lungs (pulmonary edema )
coughing

99
Q

Right Ventricular Failure

A

If the right ventricle fails it falls behind and injecting all of the blood it receives from the systemic circulation

Flat backs up into the vena cava and throughout the peripheral vascular system

This results in:
Generalized swelling throughout the body (systemic edema)
Enlargement of the liver and spleen
Pooling of fluid in the abdomen (ascites)
Distension of the jugular veins
Swelling of the ankles, feet and fingers

APHY 164 (10 decks)

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