cardiac control and coordination Flashcards
what is the AVN
atrioventricular valve
function of AVN
delays electrical impulse, allow atrial contract fully before ventricles contract
what is SAN
sinoatrial node
in right atrium
function of SAN
initiate wave of depolarisation
what happens during atrial systole
SAN initiates a wave of depolarisation, transmitted throughout the atria, atria walls contract almost simultaneously
blood forced through AV into ventricles
non-conducting tissue prevents excitation passing directly to ventricles
what happens during ventricular systole
AVN picks up wave from SAN
AVN impose slight delay, so atria can fully empty before contracting
AVN initiate own wave
wave sent through bundle of His
bundle of His splits into two branches, conducts wave to apex
purkyne fibres spread out through left and right ventricles
spread triggers contraction of ventricles, allow efficient emptying of ventricles through SLV to aorta/ pulmonary artery
what is P wave due to
depolarisation and constriction of atria
what is QRS complex due to
depolarisation and contraction of ventricles
what is T wave due to
repolarisation and relaxation of ventricles
tachycardia
heart is beating too fast
bradycardia
heart is beating too slowly
ectopic heartbeat
extra heartbeats out of normal rhythm
ventricular fibrillation
ventricles fibrillate dont contract properly
atrial fibrillation
rapid electrical impulses generated in atria
arrhythmia
abnormal rhythm of heart
e.g. atrial and ventricular fibrillation
