Flashcards in 3.2 The Heart & Cardiac Cycle Deck (44):
(Heart) What is myocardium and what does it do?
Beats continually without tiring
(Heart) what is the pericardium and what does it do?
Double layered sac covering the heart
Protects it from over expansion and infection
(Heart) the pericardial fluid is secreted to do what?
Protect the heart from jerking movements and shock
(Heart) the aorta leaves which ventricle? And what does it do?
Distributes oxygenated blood to the body
(Heart) the pulmonary arteries leave which ventricle? And what do they do?
Carry deoxygenated blood from heart to lungs
(Heart) the vena cava enters where and does what?
Delivers deoxygenated blood from body
(Heart) what do the coronary arteries do?
Deliver oxygen to the heart muscles
(Heart) blockage of the coronary arteries can result in what?
(Heart) what do valves do?
Keep blood flowing in one direction
(Heart) what are the two atrioventricular valves called?
(Heart) the bicuspid and tricuspid AV valves prevent what happening?
Backflow of blood from ventricles into atrium
(Heart) the semilunar valves allow what to happen?
Blood to be pumped out into arteries
But prevent it flowing back in
(Cardiac cycle) in diastole what are the heart muscles?
(Cardiac cycle) diastole - deoxygenated blood enters the right atrium from where?
The vena cava
(Cardiac cycle) diastole - oxygenated blood enters the left atrium from where?
The pulmonary vein
(Cardiac cycle) as atria fill with blood what increases?
(Cardiac cycle) increase in pressure forces what open?
AV valves so blood flows into ventricles
(Cardiac cycle) in atrial systole what do the walls of the atria do?
(Cardiac cycle) atrial systole pushes what?
Remaining blood into ventricles
(Cardiac cycle) in ventricular systole what do the ventricles do?
(Cardiac cycle) when the ventricles contract what increases?
Pressure in the ventricles
(Cardiac cycle) increased pressure in the ventricles forces what two things to happen?
AV valves to shut
semilunar valves to open
(Cardiac cycle) when the semilunar valves open blood is forced where?
Out of heart to lungs and body
(Heartbeat) what is the SAN and where is it found?
Sino atrial node
Found in wall of right atrium
(Heartbeat) the SAN does what?
Sets heartbeat by sending out waves of electrical activity to atria walls
(Heartbeat) the waves the SAN sends causes the right and left atria to do what?
Contract at the same time
(Heartbeat) what prevents the waves being passed directly from atria to ventricles?
Non conducting collagen tissue
(Heartbeat) the waves are transferred from the SAN to where?
(Heartbeat) what is the AVN?
(Heartbeat) the AVN passes the waves of electrical activity to where?
The bundle of his
(Heartbeat) why is there a slight delay before the AVN reacts?
To ensure ventricles have emptied before atria contract
(Heartbeat) what is the bundle of his?
Group of muscle fibres conducting waves of electrical impulses to finer muscle in the ventricle walls
(Heartbeat) what are the finer muscle fibres in the ventricle walls called?
(Heartbeat) what does the Purkyne tissue do?
Carries impulse to walls of ventricles causing them to contract simultaneously from the bottom up
(ECGs) what does an electrocardiograph do and what is it used for?
Electrical activity of the heart
Used to check heart function
(ECGs) what is the P wave caused by?
Contraction and depolarisation of atria
(ECGs) what is the QRS complex?
Contraction and depolarisation of ventricles
(ECGs) the T wave is caused by what?
Relaxation and repolarisation of ventricles
(ECGs) the bigger the wave the more what?
(ECGs) what is the term for a heart beat that is too fast?
(ECGs) when is a heart beat too fast?
(ECGs) what is it called when heartbeat is too slow? And when is this?
(ECGs) what is an ectopic heartbeat?
Extra heart beat caused by early contraction of atria or ventricles