Cardiac Cycle

Question 1

What are the 3 stages of the cardiac cycle?

Answer 1

Atrial systole (contraction of atria)

Ventricular systole (contraction of ventricles)

Diastole (relaxation of heart)

Question 2

What happens during atrial systole/ ventricular diastole?

Answer 2

Muscles of Atria contract, pushing blood into the ventricles

This causes atrial:
Volume to decrease
Pressure to increase

Question 3

What happens during ventricular systole/ atrial diastole?

Answer 3

The atria relaxes. Once it’s relaxed the ventricles contract pushing blood out of the heart

This causes ventricular:
Volume to decrease
Pressure to increase

Question 4

What happens during (cardiac) diastole?

Answer 4

All chambers are relaxed and blood flows into the heart

Question 5

What does diastole mean?

Answer 5

Relax

Question 6

What does systole mean?

Answer 6

Contract

Question 7

What happens to volume and pressure during systole?

Answer 7

Volume decreases whilst pressure increases as heart chambers contract

Question 8

What happens to volume and pressure during diastole?

Answer 8

Volume increases whilst pressure decreases as the hearts chambers relax

Question 9

What valves open during diastole?

Answer 9

The atrioventricular valves open

as pressure in atria > pressure in ventricles

Question 10

What valves close during diastole?

Answer 10

Semi lunar valves close

As pressure in ventricles < pressure in arteries

Question 11

What happens during diastole?

Answer 11

Blood passively trickles from the atria to ventricles

Causes pressure to:
Decrease in the atria
Slightly increase in ventricles

Question 12

what muscle is known as the pacemaker and controls the cardiac cycle?

Answer 12

The myogenic muscle

Question 13

What are myocytes?

Answer 13

Polarised muscle cells found in the heart

Question 14

What do myocytes do?

Answer 14

They can reverse their charges (depolarise) causing the heart to contract

Question 15

What is the SAN?

Answer 15

Its found in the upper wall of the right atrium and sets the base heart rate

Question 16

What does the SAN do?

Answer 16

The SAN initiates a wave of depolarisation causing the atria walls to contract almost simultaneously

Question 17

What does the AVN do?

Answer 17

The AVN after a short delay, depolarises after the SAN and causes the ventricles to contract once all the blood has left the atria

Question 18

What type of blood do the arteries transport?

Answer 18

Arteries carry oxygenated blood with the exception of the pulmonary artery

Question 19

What type of blood do veins carry?

Answer 19

Veins transport deoxygenated blood with the exception of the pulmonary vein

Question 20

What is the endothelium?

Answer 20

It is the inner lining of all blood vessels. It is made of a single layer of cells.

they are smooth to reduce friction with the flowing blood

Question 21

what are elastic fibres?

Answer 21

they are made out of the protein elastin and provide flexibility allowing the blood vessel to stretch and recoil.

This evens out surges of blood from the pumping heart, enabling a continuous flow

Question 22

What is the smooth muscle?

Answer 22

It provides strength to withstand high blood pressure. its main role is to contract and relax, altering the flow of blood to particular tissues.