Cardiac Cycle (Midterm 2) Flashcards
What is bulk flow?
rapid flow of blood throughout the body due to pressures by the pumping action of the heart
What is the atrium?
the upper chambers of the heart
What is the ventricle?
the lower chambers of the heart
What is pulmonary circulation?
includes blood pumped from the right ventricle through the lungs to the left atrium
What is systemic circulation?
(continuing from the pulmonary circulation) blood is pumped from the left ventricle through the organs and tissues (except lungs) then to the right atrium
What are arteries?
blood vessels carrying blood AWAY from the heart
What are veins?
blood vessels carrying blood TO the heart
What is an aorta?
part of the systemic circuit, the biggest single large artery in your body
What are arterioles?
smaller arteries branched off from normal arteries
What are capillaries?
very small vessels
What are venules?
unity of capillaries to form a larger diameter vessel
What are the two largest veins in your body?
superior and inferior vena cava
Where does the superior vena cava carry blood from?
anywhere above the heart
Where does the inferior vena cava carry blood from?
anywhere below the heart
Which side of the heart pumps blood into the pulmonary circuit?
the right side
Which side of the heart pumps blood into the systemic circuit?
the left side
Why are the atrioventricular valves bigger?
for a larger amount of flow during the filling phases
What controls the opening and closing of the semilunar valves?
based off of the pressure of the arteries outside
What happens to the AV valves when the ventricles contract, what does the blood do? (blood is in the ventricles)
blood presses up against the AV valve cusps forcing them to close and prevents back flow
What happens to the AV valves when the ventricles are relaxed?
blood entering the atria pushes the AV valves open down to the ventricles = fills up ventricles
What is the purpose of papillary muscles and chordae tendineae?
to prevent the backflow of blood from ventricles to atria
When does the closure of AV valves occur?
when the pressure in the ventricles is greater than the pressure in the atria
What happens to the semilunar valves when the ventricles contract?
open, blood presses up the semilunar cusps= forces valves to open = blood flows into aorta/pulmonary arteris
Are the direction of the cusps between the semilunar valves and AV valves the same or opposite?
opposite
What happens to the semilunar valves when the ventricles relax?
blood in the aorta/pulmonary arteries press down against the cusps = forces them closed
What is diastole?
period of relaxation – filling of heart with blood
What is systole?
period of contraction
In the cardiac cycle, what contracts? (atria or ventricles?)
ventricles
What marks the beginning of ventricular systole?
ventricular contraction causing AV valves to close
What forces the semilunar (SL) valves to open?
pressure build-up in ventricles
Is the passive ventricular filling phase diastole or systole? What phase number is this?
diastole, 1
What happens during the passive ventricular filling phase?
AV valves open = blood flows into relaxed ventricles; responsible for most of the ventricular filling
Is the active ventricular filling phase diastole or systole? What phase number is this?
diastole, 1
What happens during the active ventricular filling phase?
the atria begins to contract which completes the ventricular filling phase
Is the period of isovolumic contraction phase diastole or systole? What phase number is this?
systole, 2
Why doesn’t the semilunar valves open during the isovolumic contraction phase?
the pressure in the ventricles is still too low to open them
What happens during the isovolumic contraction phase?
ventricular contraction causes/keeps the AV valves closed
Is the period of ejection phase diastole or systole? What phase number is this?
systole, 3
What happens during the period of ejection phase?
continued ventricular contraction pushes blood out of the ventricles = opening semilunar valves
What happens when the ventricles relax?
intraventricular pressure falls = SL valves close & blood flows back from arteries = fills up SL valve cusps = reinforces closure
Is the period of isovolumic relaxation phase diastole or systole? What phase number is this?
diastole, 4
What marks the beginning of ventricular diastole?
when SL valves close
What happens during the period of isovolumic relaxation phase?
very brief pause in cardiac cycle || semilunar valves all closed and no flow occurring blood flow back onto closed valves due to differences in pressure
What state are arteries in during systole?
expand to hold blood newly ejected from the ventricles
What state are arteries in during diastole?
recoil inward to send blood continuously through the rest of the vasculature
