heart activity Flashcards
where is the sino-atrial node located
right atria wall
what is the SAN
sets the rhythm of the heart beat by sending out regular waves of electrical activity to atrial walls
what does the electrical activity in the atrial walls cause
the right and left atria to contract at the same time
what prevents the wave being passed directly to the ventricles
non-conducting collagen tissue
where are the waves transferred to from the SAN
atrioventricular node
what does the AVN do
passes waves of electrical activity to the bundle of his
why is there a delay in the AVN sending signals
ensures ventricles contract when atria has emptied
what is the bundle of his
group of muscle fibres responsible for conducting electrical waves to finer muscle fibres purkyne tissue in the ventricle walls
what does the purkyne tissue cause
carries electrical waves into walls of right and left ventricle so they can contract at the same time from the bottom up
what is an ECG used for
detecting changes in electrical activity of the cardiac cycle
what is the P wave caused by
contraction (depolarisation) of the atria
what is the QRS complex
contraction (depolarisation) of the ventricles
what is the T wave
ventricle relaxation (repolarisation)
what is one full heartbeat on a ECG recording
P wave, QRS complex and T wave
what does a bigger height on the QRS complex indicate
stronger contraction
