Intro to CAS: Cardiac Physiology & the Cardiac Cycle

Right sided pressures are ____ than left sided pressures

less

AV valves are ____ in diastole

open

Semilunar valves are ____ in systole

open

Atrioventricular valves

Mitral and tricuspid valves

Semilunar valves

Aortic and pulmonic

Isovolumic relaxation time (IVRT) occurs immediately before ______

Diastole

During IVRT all 4 heart valves are _____

closed

During IVRT ventricular pressure ____ in preparation of ventricular diastole while atrial pressures ____

drop, rise

Isovolumic relaxation time

when the ventricles relax and the pressure decreases, leading to closure of the valves.

The first phase of the cardiac cycle

isovolumic relaxation time

The second phase of the cardiac cycle

Diastole

Diastole

Period of relaxation when ventricles fill with blood

During early diastole, the ventricles are at their lowest pressure and
they experience ____ ___________ _______ quick filling known as

rapid ventricular filling

Rapid early filling (part of diastole)

Accounts for 75% of ventricular filling

Diastasis (part of diastole)

As ventricular walls stretch, atria and ventricles essentially reach equilibrium

Atrial Kick

when diastole is near complete, the atria contract causing a small amount of blood to enter the ventricles

Isovolumic contraction time

Is the phase when the ventricles contract but no blood is ejected, causing pressure to increase.

Systole

Period of contraction of ventricles when blood is pushed out of the heart

Third phase of the cardiac cycle

isovolumic contraction time (IVCT)

Fourth phase of contraction time

systole

Ventricular pressures exceed pressure in AV/PV, valves are pushed
open and blood is sent to the great arteries (aorta/pulmonary artery

Systole

Why do MV and TV remain closed during systole?

so blood will not travel from the ventricles back into atria

What creates the 2nd heart sound?

As pressures in the aorta & pulmonary artery increase, ventricular
systole completes and pressures drop in the ventricles, AV & PV close creating 2nd heart sound