The Heart Flashcards
The circulatory system has two divisions: a(n) __________ circuit that furnishes blood to the entire body and a(n) ________ circuit that functions only for gas exchange with the air in the lungs.
Systemic; pulmonary
The heart is enclosed in a fibrous, two-layered sac called the ________.
Pericardium
Obstruction of a coronary artery leads to ________, sudden death of a part of the heat muscle.
Myocardial infarction
The ventricles have _________ muscles that anchor stringy _________ to prevent the atrioventricular valves from prolapsing during ventricular systole.
Papillary; tendinous cords
__________ occurs when different areas of the heart muscle receive electrical stimuli at different times.
Ventricular fibrillation
Normally, each cycle of cardiac contraction is set off by its pacemaker, the ___________.
SA node
When the heart fails in the CHF, _______ edema occurs.
Pulmonary
The action potentials of cardiac muscle exhibit a plateau, unlike those of skeletal muscle and neurons, resulting from a prolonged influx of _______ ions.
Calcium
The contraction of any heart chamber is called _______, and its relaxation is called __________.
Systolic; diastolic
The amount of blood ejected by one contraction of a ventricle is called its ________, and the percentage of its blood ejected is called its _________.
Stroke volume; ejection fraction
Agents such as epinephrine are said to have a positive ________ effect because they increase the heart rate and a positive __________ effect because they increase the force of its contractions.
Chronotropic; inotropic
Pressure in the large arteries that oppose ejection of blood from the ventricles.
Afterload
The left atrioventricular valve
Desmosome
Abnormal heartbeat
Arrhythmia
The normal heartbeat governed by the SA node
Sinus rhythm
