Cardiac Cycle

Question 1

atrial systole

Answer 1

• the contraction of the right and left atria pushing blood into the ventricles

Question 2

atrial distole

Answer 2

• the period between atrial contractions when the atria are repolarizing

Question 3

Ventricular systole

Answer 3

• Contraction of the right and left ventricles pushing blood into the pulmonary arteries and aorta

Question 4

ventricular distaole

Answer 4

• the period between ventricular contractions when the ventricles are repolarizing

Question 5

Preload

Answer 5

• refers to the tension in the ventricular wall at the end of diatole. it reflects the venous filling pressure that fills the left ventricle during diatole

Question 6

afterload

Answer 6

-Refers to the forces that impede the flow of blood out of the heart, primarily the pressure in the peripheral vasculature, the compliance of the aorta, and the mass and viscosity of blood

Question 7

stroke volume

Answer 7

• Refers to the volume of blood ejected by each contraction of the left ventricle
• normal SV range from 60-80ml depending on age, sex, and activity

Question 8

Cardiac output CO

Answer 8

• the amount of blood pumped from the left or right ventricle per minute
• it is equal to the product of stroke volume and HR
• normal CO for an adult male at rest is 4.5-5.0 L/min with women producing slightly less.
• CO can increase up to 25 l/min during exercise

Question 9

Venous return

Answer 9

• the amount of blood that returns to the right atrium each minute. this is similar in volume to the CO.
• Because teh cardiovascular system is a closed loop, venous return must equal CO when averaged over time