4.3.5 - The Heart

Question 1

What are the 3 stages of the cardiac cycle?

Answer 1

Atrial systole
Ventricular systole
Diastole

Question 2

What does systole mean?

Answer 2

A period of contraction

Question 3

What does diastole mean?

Answer 3

A period of relaxation

Question 4

What happens during atrial systole?

Answer 4

Atria full of blood and ventricles relaxed
Both atria contract and blood is passed into ventricles
Atrioventricular valves open

Question 5

How much blood passively flows into the ventricles during atrial systole?

Answer 5

70%

Question 6

What happens during ventricular systole?

Answer 6

Atria relax
Ventricle walls contract, forcing blood out
Pressure of blood forces atrioventricular valves to shut
Pressure of blood opens semi-lunar valves
Blood passes into aorta and semi lunar valves

Question 7

What happens during Diastole?

Answer 7

Both atria and ventricles are relaxed
Pressure in ventricles fall below pressure of blood in arteries
Blood in arteries causes semi lunar valve to shut
All muscles in hear relax
Blood from vena cava and pulmonary veins enter the atria.

Question 8

When does the pressure of the atria increase?

Answer 8

During atrial systole, walls of the atria press inwards increasing the pressure and pushing blood to the ventricles.

Question 9

When does the pressure of the atria and ventricles decrease?

Answer 9

During diastole, atria and ventricles relax.