cardiovascular system Flashcards
aorta
main artery from heart to body carrying oxygenated blood
pulmonary artery
from heart to lungs carrying de-oxygenated blood
pulmonary vein
from lungs to heart carrying oxygenated blood
vena cava
major vein from body to heart which brings de-oxygenated blood
coronary artery
artery which supplies cardiac muscle with oxygen rich blood
sinoatrial node (SAN)
heart’s pacemaker responsible for the regular contraction of the heart muscle
why is the heart myogenic?
contracts spontaneously without being stimulated by nerve cells
Bundle of His
collection of cells that transmit electrical signals from the AV node to ventricles
Purkinje fibres
branched fibres that carry electrical signals into the ventricles to allow contraction
bicuspid valve
prevents backflow of blood from left ventricle to left atrium
function of semi-lunar valve
prevents backflow from arteries into ventricles
septum
cardiac muscle that divides the left & right side of the heart
function of P wave
atria systole - atria contracts
blood is squeezed into the ventricles
function of T wave
repolarisation of ventricles as they relax and recover
ventricular diastole
QRS complex
excitation of ventricles - ventricles contract
corresponds to the spread of the impulse through ventricles when contracting
bradycardia
slow heart rate
tachycardia
fast heart rate
arrhythmia
indicated by abnormal heart beat & heart is beating irregularly
define cardiac output
the volume of blood out of the heart in one minute
how is cardiac output calculated?
stroke volume x heart beat per minute
stroke volume
volume of blood pumped out the heart by ventricles with each heartbeat
define cardiac cycle
coordinated sequence of contractions and relaxations of the heart muscle which causes the blood to flow from the atria, into the ventricles and then the arteries
atria systole
when atria is contracting
define diastole
when the cardiac muscle is in a relaxed state