Cardiac Cycle and Sounds Flashcards
why does atrial pressure increase during ventricular systole?
blood continues to return to the heart but cannot move into the ventricles
what is the diastolic pressure in the ventricles?
close to 0
what is the ventricular volume at the beginning of the atrial contraction?
around 100-120 mL
when does the aortic pressure decrease?
it is decreasing through atrial contraction and even into ventricular contraction
what happens when the ventricular pressure in the ventricles exceed the atrial pressure?
the AV valves close
what is the period known as isovolumetric contraction?
the ventricular volume remains constant while the ventricular pressure increases dramatically
what dictates what pressure the ventricle must exceed before the aortic valve opens?
the diastolic pressure
when do the aortic and pulmonary valves close?
when the pressure in the ventricles drop below the arterial pressure
at the point of divergence between the aortic pressure and the ventricular pressure, what happened?
closure of the aortic valve and pulmonary valve
the closing of the aortic valve produces what in the aortic pressure wave?
the dicrotic notch
what is isovolumetric relaxation?
no blood enters or leaves the ventricle while it is relaxing because both the AV and aortic valves are closed- all the valves are closed, blood can’t get in
what happens when the atrial pressure exceeds the ventricular pressure?
the AV valves will open
why does the aortic pressure continue to drop during atrial systole and ventricular diastole?
the blood is leaving the aorta and flowing into the smaller vessels in the periphery
what is the rate of the peripheral run-off determined by?
the resistance to blood flow
What is the a wave created by?
atrial contraction
why is the jugular pressure clinically important?
bc if blood starts to back up due to the heart’s inability to pump blood- the jugular pressure will be affected very early
what is the c wave created by?
isovolumetric contraction of the ventricles- the AV valves that are closed bulge back into the atria
what is the v wave created by?
blood returning back to the atria
what is the first heart sound (S1) associated with?
closure of the AV valves- blood in the atria hitting the closed valves as it tries to enter the ventricle
what is the second heart sound (S2) associated with?
closing of the aortic and pulmonary valves- blood in the aorta/pulmonary artery back flows and bounces off the closed valves
what is the third heart sound (S3) associated with?
blood rushing into the ventricle during the rapid filling phase
when is the fourth heart sound heard?
during atrial contraction - before the first heart sound
what is the fourth heart sound the result of?
the last little bit of blood squeezing into the ventricle
when is a murmur heard (2 reasons)?
blood is moving in a direction it shouldn’t be moving or blood is having a hard time moving in the direction it should be moving in
what is blood moving in a direction it shouldn’t associated with?
an incompetent valve (aka regurgitation)
what is blood having a hard time moving in the direction it should be moving associated with?
a valve is open but not fully–> open valve stenosis
when might you hear a systolic murmur when blood is moving in a direction it shouldn’t be moving?
when blood moves back into the atria caused by regurgitation
when might you hear a systolic murmur when blood is having a hard time moving in the direction it should be moving in?
blood can’t get into the aorta/pulmonary artery due to stenosis
when might you hear a diastolic murmur when blood is moving in a direction it shouldn’t?
when blood is moving back from the aorta into the ventricle
when might you hear a diastolic murmur when blood is having a hard time moving in the direction it should be moving?
when blood can’t get into the ventricle due to stenosis
