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1. The layer of the heart that forms the smoothprotective lining of the heart chambers and valvesis the

A. EndocardiumB. Myocardium

C. Epicardium

D. Parietal pericardium

2. Which layer of the following serves the dualpurpose of forming the inner layer of thepericardium and forming the outermost wall of theheart?

A. Fibrous pericardium

B. Parietal pericardium

C. Visceral pericardium

D. Myocardium

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3. The ____ has the thickest wall because it pumpsblood to the _______

A. right atrium; systemic circuit

B. right ventricle; lungs

C. left atrium; lungs

D. left ventricle; systemic circuit

4. Freshly oxygenated blood enters the heart throughthe ____, and is pumped out the _____

A. Right atrium; aorta

B. Left atrium; aortaC. Right ventricle; pulmonary arteries

D. Left ventricle; pulmonary arteries

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The Cardiac Cycle

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The Cardiac Cycle Heart actions are regulated

Heart actions are a series of events

cardiac cycle

oAtria contract ( atrial systole) theventricles relax (ventricular diastole)

oVentricles contract (ventricular systole)

the atria relaxo Then atria and ventricles briefly relax

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Cardiac Conduction System

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Structures of the System

SA Node = SinoatrialNode

AV Node =Atrioventricular Node

Generates rhythmiccontractionso Pacemaker of the heart

Impulses spread thoughatria

Impulses spread to the

AV Node

Connected to SA nodeby junctional fibers

o SA Node conductsimpulses slowly

AV Node conductsquickly

o Slow impulse time for SAallows time for atria tocontract completely soall blood empties intoventricles

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Structures of the SystemAV Bundle =

atrioventricular bundle Purkinje Fibers

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Receives impulses fromthe AV node

Impulses move rapid Passes through

interventricular septum

Branches into left and

right sides thenbranches into purkinjefibers

Carry fibers into theventricular

myocardium

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Overview of parts1. SA Node

2. Atrial syncytium

3. Junctional fibers

4. AV node5. AV bundle

6. Bundle branches

7. Purkinje fibers

8. Ventricular syncytium

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Electrocardiogram

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What is it?

Recoding of electrical changes that occur in themyocardium during the cardiac cycle.

Body fluids can conduct electrical currents so thechanges can be detected on the bodys surface.

Normal ECG pattern includes several waves duringeach cycle.

Up and down movements indicate electricalchanges in myocardium.

Between cycles fibers are polarized so no electricalchanges.o Shows up as marks on the baseline

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What do the letters mean?

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Use your textbook tofind what each lettermeans.

P wave

QRS complex

S T segment

T wave

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What do the letters mean?

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P waveo Atrial depolarization

o Atrial systole

QRS complexo Ventricular depolarization

o Hides record of atrialrepolarization

S T Segmento Ventricular systole

T waveo Ventricular repolarization

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Blood Pressure

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Arterial Blood PressureAlternate expanding arecoiling of arterialwalls is felt as a pulse.

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Systolic Pressureo Max pressure achieved

during ventricularcontraction

o First number recorded

Diastolic pressureo Ventricles relax, arterial

pressure drops

o Lowest pressure thatremains in arteries beforethe next ventricularcontraction

o Last number recorded

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