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29 Cards in this Set
- Front
- Back
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cardiovascular system
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includes heart, blood vessels, and blood
function= -closed system-O2 poor blood and O2 rich blood separated -blood flows in one direction -creates blood pressure-move blood -regulates amount of blood supply |
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Pericardium of the Heart
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-surrounds and protects heart
-2 main parts ---fibrous pericardium ---serous pericardium |
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Fibrous Pericardium
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outer layer
tough, non elastic, dense irreg, connective tissue function: -prevents overstitching of heart -protection -anchors heart in the cavity |
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Serous Pericardium
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thinner, double layer around the heart
under pericarium 2 layers: -parital layer -visceral layer |
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Parietal layer
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outer layer
fused to fibrous pericardium |
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visceral or epicardium layer
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inner layer
tightly adhered to heart part of outer heart wall |
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pericardial cavity
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between the serous layers
contains pericardical fluid (serous fluid) function=reduce friction as heart moves |
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layers of the heart wall
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epicardium
myocardium endocardium |
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epicardium
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external layer
visceral layer of serous pericardium adipose tissue and fibroelastic tissue thickens over ventricles houses major coronary artieries, lymph vessels |
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myocardium
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middle layer
95% of heart wall-cardiac muscle pumps the heart |
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endocardium
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internal layer
provides smooth lining of chambers and covers valves contains specailized muscle fibers-purkinje fibers |
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heart chambers
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atria
ventricles |
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atria
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2 upper chambers
recieves blood returning to heart from vains thinner walls |
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ventricles
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2 lower chambers
left ventricle thicker wall eject blood from heart to arteries |
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heart valves
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atrioventricular
semilunar valve bicuspid aortic semilunar |
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atrioventricular valve
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separate atria from ventricles
tricuspid valve= -3 cusps (flasps) -moves blood from right atrium into right ventricle |
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semilunar valves
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resemble half moons
pulmonary semilunar valve= -blood from right ventricle to pulmonary trunk and arteries |
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bicuspid valve
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aka mitral valve
2 cusps pumps blood from left atrium to left ventricle |
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aortic semilunar valve
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thicker than pulmonary
blood from lft ventricle to aorta |
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heart valve operation
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atrioventricular valves
-open and close by chordae tendineae ---fibrous strings attacted to valve -papillary muslce attatched to chordae tendinea contract to prevent valve from swinging back into atria semilunar valves -closed when relaxed -open when contracted |
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Cardiac cycle
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all events that occur during one heartbeat
avg 70 beats/min about .85 sec/beat |
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heart beats due to:
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autorythmic fibers-special cardiac muscle fibers
-self-excitable -repeatedely generates action potentials -function: ---pacemaker-set rythm ---form cardiac conduction system -----network of special fibers in heart |
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Steps in cardiac conduction system
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1.) begins in sinatrial node
-right atrial wall-hearts natural pacemaker -spontaneous depolarizations that trigger action potentials -atria contraction 2.) atrioventricular node -atria empties blood into ventricles 3.)atrioventricular bundle aka bundle of HIS -action potentials from atria to ventricles 4.) Right and Left bundle branches -potentials from interventriclular septum to apex 5.) purkinje fibers -potentials at apex upward to ventricular myocardium -ventricles contract to move blood to semilunar valves |
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Electrocardiogram
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composite record of action potentials produces by heart muscle
use electrodes to record: -2 arms, 2 legs, 4-6 around hear -look at 12 different tracings of activity -determines: --1.) a normal conducting pathway --2.) enlarged heart --3.) damaged heart regions --4.) cause of chest pain |
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ECG Waves
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1.) P wave
-small upward deflection -atrial depolarization (contraction) 2.)QRS Wave -rapid ventricular depolarization 3.) T wave -ventricular repolarization ---occurs just as ventricles relax |
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Correlation of ECG Waves and Systole
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systole-phase of contraction
diastole-phase of relaxation ECG waves predict timing of atria and ventricle systole and diastole |
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atrial systole
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top of P wave to just before Q wave
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ventricle systole
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top of P wave to just before Q wave
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Relaxation period
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