heart Flashcards
(12 cards)
describe the structure of the heart
2 atria 2 ventricles. blood goes back to heart after lungs to maintain pressure. valves between chambers stop blood flowing backwards. right and left atrioventricular valve
pulmonary artery right side vena cava
left = aorta pulmonary vein
semi lunar valve in aorta and pulmonary artery prevents blood flowing back into the heart
role of artery vena cava pulmonary artery pulmonary vein
aorta blood left ventricle to body oxygenated
vena cava blood from body to right atria deoxy
pulmonary vein blood from lungs to heart oxy
pulmonary artery blood from heart to lungs deoxy
what does myogenic mean
heart beats itself
what are coronary arteries
arteries around the outside of the heart that provide it with oxygen
why is there a short delay between electrical wave entering atrioventricular node and leaving
lets atria empty and ventricles to fill before the ventricles contract
theres a layer of non conductive tissue between atria and ventricles
describe the cardiac cycle
diastole relaxation- blood in the atria forced atrioventricular valves to open. semi lunar valves close and pressure is lower in ventricles than atria
atrial systole- SAN transmits impulse to atria. atria contracts blood forced into ventricles
ventricular systole- wave of electrical activity passes to AVN from atrial muscle. passes impulse to bundle of His then to smaller muscle fibres at bottom of ventricles. ventricles contract from bottom up blood out
whats the role of the SAN
sends out electrical impulses
initiates heartbeat
acts as a pacemaker
stimulates atria to contract
whats the difference between max pressure in atria and ventricles
pressure in ventricle can be higher than atrium as it has more muscle so contractions are also stronger
how does blood move
down a pressure gradient
when volume decreases pressure increases
pressure increases volume decreases e.g increase pressure in atria move to ventricle
what is cardiac output and the formula
volume of blood pumped by one ventricle of the heart in 1 minute
heart rate x stroke volume
whats an important thing to remember about heart disease questions
correlation doesn’t mean causation
think of what else could’ve caused it e.g smoking
what are renal arteries and veins
what are pulmonary arteries/ veins
renal = kidney pulmonary = lungs
