The Cardiac Cycle
What is the definition of the cardiac cycle?
blood flow through the heart during one complete heartbeat
Another name for the bicuspid valve
Mitral valve
abnormal heart sounds heard when blood hits obstructions
heart murmurs
amount of blood pumped out by each ventricle in 1 minute
cardiac output
Definition of diastole
heart relaxation
Ventricular ejection
§When ventricular pressure exceeds pressure in large arteries, SL valves are forced open
Valves that create heart S1
atrioventricular (AV) valves
Bradycardia
resting heart rate slower than 60 beats/min
volume of blood pumped out by one ventricle with each beat
stroke volume
P wave
depolarization of SA node and atria
volume of blood remaining in each ventricle at end of ventricular systole
End systolic volume (ESV)
Valve that connects the left atrium and ventricle
Mitral valve
Replacements for defective valves
mechanical, animal, or cadaver valve
difference between resting and maximal cardiac output
cardiac reserve
vagal tone
Decreases rate about 25 beats/min
Following ventricular repolarization (T wave), ventricles relax
Isovolumetric relaxation: early diastole
stiff valve fails to open completely
Stenotic valves
abnormally fast resting heart rate (>100 beats/min)
Tachycardia
degree to which cardiac muscle cells are stretched just before they contract
preload
QRS complex
ventricular depolarization and atrial repolarization
Quiescent period
total heart relaxation that lasts about 0.4 seconds
condition when valves fail to close fully
Incompetent (or insufficient) valve
Hypocalcemia
low blood Ca2+ depresses the heart
sympathetic reflex initiated by increased venous return, hence increased atrial filling
atrial reflex
Electrocardiogram
(ECG or EKG) is a graphic recording of electrical activity