Term
| Where is the heart located? |
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Definition
| in the mediastinum, which extends from ribs 2 to 5 or 6, bulk of heart is left of sternum |
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Term
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Definition
| the outer fibrous covering of the heart |
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Term
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Definition
| double layered membrane with lubricating fluid between the layers |
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Term
| What are the layers of the pericardium and where are they? |
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Definition
Parietal layer is just beneath the pericardial sac
visceral layer adheres tightly to the heart muscle
there are small amounts of fluid between layers to reduce friction
excess fluid or blood between layers compresses heart-cardiac tamponade |
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Term
| What are the parts of the heart, and how does blood flow through it? |
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Definition
it is a 4-chambered pump
-superior & inferior vena cave, coronary sinus
-right atrium
-right atrioventricular valve
-right ventricle
-pulmonary semilunar valve
-pulmonary trunk & arteries
-pulmonary vein
-left atrium
-left atrioventricular valve
-left ventricle
-aortic semilunar valve
-aorta |
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Term
| what does the right atrioventricular valve do? |
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Definition
(tri-cuspid)
prevents backflow from ventricles to atria during ventricular contraction
papillary muscles & chordae tendineae prevent flaps from being blown into atria
heart murmur-when valve doesn't close properly, leaking blood produces sound |
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Term
| What's the pulmnary semilunar valve? |
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Definition
| normally closed, open when ventricular contraction forces blood out of ventricle |
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Term
| how is the blood at the pulmonary trunk & arteries? |
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Definition
| oxygen-poor blood from heart to lungs |
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Term
| blood in pulmonary veins? |
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Definition
oxygen-rich blood from lungs to heart
4 pulmonary veins |
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Term
| differences between left and right ventricles? |
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Definition
note wall thickness(each side of heart serves different circulation)
right side-pulmonary circuit(gas exchange in lungs)
left side-systemic circuit(all other body tissues) |
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Term
| Blood supplied to the heart? |
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Definition
left & rigt coronary arteries-arise from base of aorta, each branches several times
cardiac veins-travel w/ arteries, all drain into coronary sinus which empties into right atrium |
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Term
| Difference between cardiac and skeletal muscles? |
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Definition
| cardiac cells conected at intercalated discs, Ca++ & Na+ to flow directly between cells no need for nerves to contact each cell, signal flows from cell to cell & all cells contract in coordinated manner |
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Term
| What is intrinsic control? |
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Definition
| cardiac muscle cells depolarize & contract w/out external nerve signal |
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Term
| What do specialized pacemaker cells do? |
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Definition
generate action potential on their own due to unstable membrane potential
spreads to adjacent muscle cells via intercalated discs |
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Term
| What and where is the sinoatrial(SA) node? |
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Definition
| in right atrial wall, sets pace of the heart |
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Term
| where is the atrioventricular (AV) node? |
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Definition
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Term
| bundles of conducting cells |
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Definition
spread signal quickly
atrioventricular bundle-in interventricular septum
purkinje fibers-walls of ventricles |
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Term
| Contraction occurs in wave? |
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Definition
| atria first, then ventricles starting atpex (squeeze heart from bottom to top, forces blood out of vessels at top) |
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Term
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Definition
| AV node assumes pacemaker role but at slower rate |
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Term
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Definition
heart block-signal can't pass from atria to ventricles, ventricular contraction is too slow(bradycardia)
fibrillation-rapid, out-of-phase contractions; leads to death |
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Term
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Definition
intrinsic system modified by input from the autonomic nervous system
sympathetic control-neurons innervate nodes & cardiac cells to speed up heart rate
parasympathetic control-neurons innervate primarily SA & AV nodes to slow rate |
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Term
| Electrocardiogram (ECG, EKG) |
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Definition
| used to measure electrical activity(not contraction) of the heart |
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Term
| what are the waves of ECG? |
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Definition
P wave- atria depolarize
QRS complex-ventricles depolarize(obscures atrial repolarization)
T wave- ventricles repolarize |
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Term
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Definition
| heart rate is elevated (ie 180 beats/min) |
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