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Anatomy
Heart
24
Anatomy
Not Applicable
02/10/2004

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Cards

Term
Where is the heart located?
Definition
in the mediastinum, which extends from ribs 2 to 5 or 6, bulk of heart is left of sternum
Term
Pericardial Sac
Definition
the outer fibrous covering of the heart
Term
Pericardium
Definition
double layered membrane with lubricating fluid between the layers
Term
What are the layers of the pericardium and where are they?
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
Term
What are the parts of the heart, and how does blood flow through it?
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
Term
what does the right atrioventricular valve do?
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
Term
What's the pulmnary semilunar valve?
Definition
normally closed, open when ventricular contraction forces blood out of ventricle
Term
how is the blood at the pulmonary trunk & arteries?
Definition
oxygen-poor blood from heart to lungs
Term
blood in pulmonary veins?
Definition
oxygen-rich blood from lungs to heart
4 pulmonary veins
Term
differences between left and right ventricles?
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)
Term
Blood supplied to the heart?
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
Term
Difference between cardiac and skeletal muscles?
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
Term
What is intrinsic control?
Definition
cardiac muscle cells depolarize & contract w/out external nerve signal
Term
What do specialized pacemaker cells do?
Definition
generate action potential on their own due to unstable membrane potential
spreads to adjacent muscle cells via intercalated discs
Term
What and where is the sinoatrial(SA) node?
Definition
in right atrial wall, sets pace of the heart
Term
where is the atrioventricular (AV) node?
Definition
in right atrial floor
Term
bundles of conducting cells
Definition
spread signal quickly
atrioventricular bundle-in interventricular septum
purkinje fibers-walls of ventricles
Term
Contraction occurs in wave?
Definition
atria first, then ventricles starting atpex (squeeze heart from bottom to top, forces blood out of vessels at top)
Term
damage to SA node?
Definition
AV node assumes pacemaker role but at slower rate
Term
damage to AV node?
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
Term
extrinsic control?
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
Term
Electrocardiogram (ECG, EKG)
Definition
used to measure electrical activity(not contraction) of the heart
Term
what are the waves of ECG?
Definition
P wave- atria depolarize
QRS complex-ventricles depolarize(obscures atrial repolarization)
T wave- ventricles repolarize
Term
what is tachycardia?
Definition
heart rate is elevated (ie 180 beats/min)
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