the heart beat and cardiac cycle Flashcards
what is found on the wall of the right atrium
group of cells called the sino atrial nodes
what does the san produce
critical stimulus for contraction occurs here
what does the san have
a basic rhythm of stimulation which determines a heart eat
how does the atria contract
the wave of electrical activity spreads out from the san across the atria which causes the atria to contract
what is present between the atria and ventricle
a layer of non conductive tissue
what does this prevent
the waves to be passed on to the ventricles
where does the wave pass through next
the next group of cels called the atrioventricular knode between the atrias
why is there a short delay in the avn
a short delay so that the ventricles can fill up with blood before it contracts
what does the avn convey
electrical waves between the ventricle through muscle fibres called bundle of his
what do bundle of his do to the wave
conduct it through the septum to the base of the ventricle
what happens at the base of the ventricle
the bundle of his divide into the pakinje fibres
what happens at these fibres
waves are reeased which causes the ventricle to contract forcing blood out of the ventricles base upwards
what is a baroreceptor
detect a change in blood pressure in the aorta and the coronary artery
what is the chemorecptor
detect a change in ph of the blood through the aorta and the corotoid artery
what does is the medula oblangata
a reigion in the brain which controls the changes in heart beat
in the centre which increase heart rate what is it linked to
the san and the sympathetic nervous system
in the centre which decreases the heart rate what is it linked to
the san and the parasymphathetic pathway `
what is the carotoid artery
the artery which carries blood to the brain
when it detects a decrease in ph what does it cause
due to an increase in c02 (acidic) an increase of firing of nerve impulses to the medula oblangata
what does the medula oblangata do
increases the number of impulses to the san via the sympathetic nervous system
what doe sthis do at the san
increase the electrical waves which increase the heart rate
what happens when the pressure is higher than norma;
nerve impulses are sent to the medula oblangata and then sends signals down the parasympathetic nerves to san slow down heart beat
what happesn when the pressure decreases
nerve impulses are increased to medula oblnangata which then increase the nerve impulses to the san via the sympathetic nervous system to increase heart rate
