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Bio 157 Lecture > Chapter 19- Heart > Flashcards

Chapter 19- Heart Flashcards

1
Q

Pulmonary circuit

A

carries blood to the lungs for gas exchange and returns it to the heart; supplied by right side of heart
- pumps oxygen-poor blood to the lungs via the
pulmonary trunk which divides into the left and right
pulmonary arteries (deoxygenated blood)

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2
Q

Systemic circuit

A

– supplies blood to every organ of the body including other parts of the lungs and the wall of the heart; supplied by left side of heart
- Pulmonary veins return oxygen-rich (oxygenated)
blood to the heart; blood heart leaves via the aorta
and returns via the inferior and superior vena cavae

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3
Q

artery

A

systemic - oxygenated
pulmonary - deoxygenated

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4
Q

vein

A

systemic - deoxygenated
pulmonary - oxygenated

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5
Q

Position of Heart in the Thoracic Cavity

A

Heart located in mediastinum, between lungs
Base—wide, superior portion of heart,
large vessels attach here
Apex—tapered inferior end, tilts to the
left

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6
Q

Pericardium

A

-double-walled sac that encloses the heart
-Allows heart to beat without friction, provides room to expand, yet resists excessive expansion
- Anchored to diaphragm inferiorly and sternum anteriorly

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7
Q

Fibrous pericardium

A

outer wall, not attached to heart

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8
Q

Serous pericardium

A

-Parietal layer—lines fibrous pericardium
-Visceral layer (epicardium)—covering heart surface

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9
Q

Pericardial cavity

A

space between parietal and visceral layers of
serous pericardium, filled with 5 to 30 mL of pericardial fluid

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10
Q

Pericarditis

A

painful inflammation of the membranes

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11
Q

3 layers of heart wall

A

epicardium, myocardium, and
endocardium

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12
Q

Epicardium (visceral layer of serous pericardium)

A
  • Serous membrane covering heart
  • Adipose in thick layer in some places
  • Coronary blood vessels travel through this layer
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13
Q

Endocardium

A
  • Smooth inner lining of heart and blood vessels
  • Covers the valve surfaces and is continuous with endothelium
    of blood vessels
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14
Q

Myocardium

A
  • Layer of cardiac muscle proportional to workload
    -Muscle spirals around heart which produces wringing motion, vortex of the heart
  • Fibrous skeleton of the heart: framework of collagenous and elastic fibers
    -Provides structural support and attachment for cardiac muscle and anchor for valve tissue
    -Electrical insulation between atria and ventricles; important in timing and coordination of
    contractile activity
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15
Q

Two upper chambers

A

-L and R atria
-The atria are receiving chambers that
receive blood returning to the heart.

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16
Q

Two lower chambers

A

– L and R ventricles
-R ventricle wraps around the L ventricle in
a C-shape, but both ventricles have the
same volume.
-The ventricles are the “pumps” that eject
blood.

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17
Q

Atrioventricular valves (AV valves)

A

Regulate the openings between the
atria an the ventricles

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18
Q

R AV valve

A

three cusps; tricuspid
valve

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19
Q

L AV valve

A

two cusps; mitral valve

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20
Q

Chordae tendinae

A

attach the valves to the papillary muscles on the floor of the ventricle and stop valves from flipping inside out or bulging into the atria when the ventricles contract

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21
Q

Semilunar valves

A

Regulate blood flow from the ventricles
into the great arteries; both have three
cusps
aka. =Aortic valve, Pulmonary valve

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22
Q

Aortic valve

A

controls opening from L ventricle to the aorta

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23
Q

Pulmonary valve

A

controls opening from R ventricle to the pulmonary trunk

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24
Q

The Coronary Circulation

A

5% of blood pumped by heart is pumped to the heart itself through the coronary
circulation to sustain its strenuous workload
* 250 mL of blood per minute
* Needs abundant O2 and nutrients

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25
Q

Anterior interventricular branch

A

Supplies blood to both ventricles and anterior two-thirds of the interventricular septum

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25
Q

left coronary artery branches off __________

A

the ascending aorta

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26
Q

Circumflex branch

A
  • Passes around left side of heart in coronary sulcus
  • Gives off left marginal branch and then ends on the posterior side of the heart
  • Supplies left atrium and posterior wall of left ventricle
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27
Q

Right coronary artery (RCA) branches off ___________

A

the ascending aorta
-Supplies right atrium and sinuatrial node (pacemaker

28
Q

Right marginal branch

A

Supplies lateral aspect of right atrium and ventricle

29
Q

Posterior interventricular branch

A

Supplies posterior walls of ventricles

30
Q

Angina pectoris

A

-chest pain from partial obstruction of coronary blood flow
-Pain caused by ischemia of cardiac muscle
-Obstruction partially blocks blood flow
-Myocardium shifts to anaerobic fermentation, producing lactate and thus
stimulating pain

31
Q

Myocardial infarction

A

-sudden death of a patch of myocardium resulting from long-term obstruction of coronary circulation
-Atheroma (blood clot or fatty deposit) often obstructs
coronary arteries
-Cardiac muscle downstream of the blockage dies
-Heavy pressure or squeezing pain radiating into the left arm
-Some painless heart attacks may disrupt electrical
conduction pathways, leading to fibrillation and cardiac arrest

32
Q

Cardiomyocytes

A

striated, short, thick, branched cells, one central nucleus surrounded by light-staining mass of
glycogen

33
Q

Intercalated discs

A

join cardiomyocytes end to end with three features:
interdigitating folds, mechanical junctions, and electrical junctions

34
Q

Sinus rhythm

A

normal heartbeat triggered by the SA node
* Adult at rest is typically 70 to 80 bpm (vagal tone)

35
Q

Ectopic focus

A

a region of spontaneous firing other than the SA node
* May govern heart rhythm if SA node is damaged

36
Q

Nodal rhythm

A

if SA node is damaged, heart rate is set by AV node, 40 to 50 bpm
* Other ectopic focal rhythms are 20 to 40 bpm and too slow to sustain life

37
Q

P wave

A

SA node fires, atria depolarize and contract; atrial systole begins 100 ms after SA signal

38
Q

PR interval

A

signal conduction through AV node, before activating ventricles

39
Q

QRS complex

A

ventricular depolarization; complex shape of spike due to
different thickness and shape of the two ventricles

40
Q

QT interval

A

duration of ventricular depolarization; shorter during exercise

41
Q

ST segment

A

ventricular systole; corresponds to plateau in myocardial action potential

42
Q

T wave

A

ventricular repolarization and relaxation

42
Q

difference between cardiac and sk AP

A

-prolonged repolarization
-action potential is longer
-much longer refractory period

43
Q

ventricular fibrillation

A
  • Serious arrhythmia caused by electrical signals traveling randomly
  • Heart cannot pump blood; no coronary perfusion
  • Hallmark of heart attack
  • Defibrillation—strong electrical shock with intent to depolarize entire myocardium and reset heart to sinus rhythm
44
Q

Atrial fibrillation

A

chaotic depolarizations that do not
stimulate ventricles; common in elderly and alcoholics

45
Q

Heart block

A

failure of any part of the cardiac conduction system to conduct signals, usually result of disease or degeneration of conduction system

46
Q

Premature ventricular contraction

A

ventricular ectopic focus with extra beat; may result from stress, lack of sleep or stimulants

46
Q

what governs fluid movement

A

pressure causes flow and resistance opposes it

47
Q

the flow of fluid

A
  • Fluid will only flow if there is a pressure gradient (pressure difference)
  • Fluid flows from high-pressure point to low-pressure point
  • Pressure measured in mm Hg with a manometer (sphygmomanometer for BP)
48
Q

Cardiac cycle

A

one complete contraction and relaxation of all four chambers of the heart, total duration of the cardiac cycle is approx. 0.8 second in a heart
beating 75 bpm

49
Q

diastole

A

relaxation

50
Q

systole

A

contraction

50
Q

Opening and closing of valves are governed by these pressure changes

A
  • AV valves limp when ventricles relaxed
  • Semilunar valves under pressure from blood in vessels when
    ventricles relaxed
51
Q

First heart sound (S1)

A

louder and longer “lubb,” occurs with closure of
AV valves, turbulence in the bloodstream, and movements of the heart wall

52
Q

Second heart sound (S2)

A

softer and sharper “dupp,” occurs with closure of
semilunar valves, turbulence in the bloodstream, and movements of the heart wall

53
Q

Ventricular filling – three phases

A

a) Rapid filling
b) Diastasis (slower filling) – P wave at end
c) Atrial systole

54
Q

Isovolumetric contraction

A
  • Ventricles depolarize, generate the QRS
    complex, ventricles contract
55
Q

Ventricular ejection

A
  • Ventricular pressure exceeds arterial pressure;
  • T wave occurs late in this phase
56
Q

Isovolumetric relaxation

A
  • Ventricular diastole
57
Q

Control centers are in the medulla oblongata

A

-1 – 4 show the sympathetic autonomic nervous
system (ANS) innervation to the heart (via the
cardiac nerves)
-5 & 6 show the parasympathetic autonomic
nervous system innervation to the heart (via the
vagus nerve, CNX)

58
Q

CO = SV x HR

A

-Cardiac Output = CO (ml/min or L/min), the amount of blood ejected per minute
-SV = stroke volume (ml/beat)
-HR = Heart Rate (beats/min)

59
Q

Tachycardia

A
  • resting adult heart rate above 100 bpm
  • Stress, anxiety, drugs, heart disease, or fever
  • Loss of blood or damage to myocardium
60
Q

Bradycardia

A

-resting adult heart rate of less than 60 bpm
-In sleep, low body temperature, and endurance-trained athletes

61
Q

Positive chronotropic agents

A

factors that raise the heart rate

62
Q

Negative chronotropic agents

A

factors that lower the heart rate

63
Q

Three variables govern stroke volume

A
  • Preload - the amount of tension in ventricular myocardium immediately before it begins to contract
  • Contractility - refers to how hard the myocardium contracts for a given preload
  • Afterload - sum of all forces opposing ejection of blood from ventricle
64
Q
A

Bio 157 Lecture (4 decks)

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