Midterm 3 Flashcards
What are the 2 main period of the cardiac cycle and what do they do?
systole: ventricle contraction
diastole: ventricle relaxation
Why do valves open passively?
due to pressure gradients
What valves open when atrial pressure is greater than ventricular pressure?
AV
What valves open when ventricular pressure is greater than atrial pressure?
semilunar
What are the 4 phases of the cardiac cycle?
- ventricular filling
- isovolumetric ventricular contraction
- ventricular ejection
- isovolumetric ventricular relaxation
What is the first phase of the cardiac cycle?
ventricular filling: when atria pressure is greater than the ventricles and AV valves are open
What is the second phase of the cardiac cycle?
isovolumetric ventricular contraction: increases pressure due to ventricle contraction, AV and semilunar valves are closed and no blood enters or exits. the ventricle
What is the third phase of the cardiac cycle?
ventricular ejection (pumping): ventricle pressure is greater than in the arteries, semilunar valves open
What is the fourth phase of the cardiac cycle?
isovolumetric ventricular relaxation: ventricle can relax which decreases pressure, AV and semilunar valves are closed and no blood enters or exits the ventricle
What is an active phase?
when no atria or ventricles contract
What is a passive phase?
when atria contract
When is heart sound 1 between?
atrial systole and isovolumetric ventricular contraction
When is heart sound 2 between?
ventricular ejection and isovolumetric ventricular relaxation
What is the fourth phase of the cardiac cycle?
isovolumetric ventricular relaxation: ventricle can relax which decreases pressure, AV and semilunar valves are closed and no blood enters or exits the ventricle
- pressure is less than aorta so aortic valve closes
When is ventricular filling passive until?
until the atrium contracts
How long does ventricular systole last and how long is the entire cycle?
systole: 0.3 seconds
entire: 0.8 seconds
(therefore diastole is 0.5 seconds)
What makes the sound “lubb”?
the closure of the tricuspid and mitral valves at the beginning of systole (AV valve)
What makes the sound “dubb”?
the closure of the aortic and pulmonary semilunar valves at the beginning of diastole
What is the dicrotic notch?
a brief rise in aortic pressure caused by back flow of blood rebounding off semilunar valves (closure of aortic valve at the end of systole)
What is systolic pressure?
the pressure in the aorta in the first phase (ventricles to aorta)
What is diastolic pressure?
the lowest pressure in the aorta when blood leaves it
What makes the sound “lubb”?
the closure of the tricuspid and mitral valves at the beginning of systole (AV valves close simultaneously)
- soft sound
What makes the sound “dubb”?
the closure of the aortic and pulmonary semilunar valves (SL valves simultaneously) at the beginning of diastole
- louder sound
What does the aorta do during systole/diastole?
stores E during systole as the walls expand then releases it during diastole as the walls recoil inwards