Cardio Flashcards
name the layers outside the heart
fibrous pericardium, parietal pericardium
name the layers on the heart
visceral pericardium, myocardium, endocardium
where does pericardial fluid lie?
between the parietal and visceral pericardium
function of the pericardial fluid
prevents friction between the visceral and parietal pericardium when the heart contracts
which cells of the heart contract?
myocardial cells
what cells are in contact with the blood, inner lining of the heart
endocardium
what is the cardiac cycle?
the events that occur when blood is being moved in and out of the ventricles
what is systole
ventricles are contracting
what is diastole
ventricles are relaxing
how long is systole?
0.3s
how long is diastole
0.5s
cardiac cycle length
0.8s
typical resting heart rate, and range of healthy heart rates
72bpm, 60-100bpm
what does the cardiac cycle represent
one heartbeat
what events occur in systole?
ventricular isovolumic contraction and ejection
what is isovolumic contraction?
the ventricles contract but the volume of blood in the ventricles does not change
all valves are closed
during ejection, how much of the blood leaves the ventricles?
2/3rds
what events happen in diastole?
isovolumic relaxation, rapid inflow of blood, diastasis, atrial systole
what causes the rapid of inflow of blood into the ventricles
passive movement of blood from atria to ventricles down a pressure gradient
pressure in the atria exceeds ventricles
what is isovolumic relaxation
ventricles relax, all valves shut
ventricular pressure falls to below aortic pressure
what is rapid inflow?
pressure in the atria exceeds ventricles
AV valves open, blood flows from the atria to the ventricles down a pressure gradient
atria passively fill and blood trickles into ventricles
80% ventricle filling here
what is diastasis
Pressure in the ventricles approaches pressure in the atria
pressure gradient means passive filling rate falls
what is atrial systole
contraction of atria to fully empty into ventricles
what is the first heart sound and what causes it?
lubb, AV valve shuts