heart and conduction

atrioventricular (AT) valves

tricuspid, mitral

semilunar valves

pulmonary, aortic

separates right and left atria

interatrial septum

separates left and right ventricles

interventricular septum

3 layers of the heart

epicardium, myocardium, endocardium

junctions that connect heart muscles

intercalated discs

intrinsic conduction system

sinoatrial (SA) node, atrioventricular (AV) node, AV bundle, bundle branches, subendocardial conducting network (purkinje fibers)

p wave

atrial depolarization

qrs complex

ventricular depolarization

t wave

ventricular repolarization

systole

ventricular contraction

diastole

ventricular relaxation

how long is the cardiac cycle

one complete heartbeat where both atria and ventricles contract then rest, 1.6 seconds

quiescent period

total heart is relaxed (0.4 seconds)

cardiac cycle

ventricular filling, ventricular filling with atrial contraction, isovolumetric contraction, ventricular ejection, isovolumetric relaxation

ventricular filling

atrial pressure > ventricular pressure, diastole A and V, AV valves opened, SL valves closed

ventricular filling with atrial contraction

atria contract to complete filling of ventricles, systole A, diastole V, AV valves open, SL valves closed

isovolumetric contraction

contraction of ventricles, diastole A, systole V, AV and SL valves closed

ventricular ejection

ventricular pressure continues to rise and blood is ejected, diastole A, systole V, AV valves closed, SL valves open

isovolumetric relaxation

ventricles relax, diastole A and V, AV and SL valves closed

lub

closure of AV valves, beginning of systole

dup

closure of semilunar valves, end of systole

blood pressure cuff

sphygomomanometer

heart rate above 100

tachycardia

heart rate below 60

bradycardia