Module 3: Heart & Cardiac Cycle

Question 1

State 3 reasons why larger organisms need transport systems

Answer 1

Higher metabolic rate
Small SA:V
Cells too deep in the body - too large a diffusion path

Question 2

Name the 4 blood vessels attached to the heart

Answer 2

Vena Cava
Pulmonary Artery
Pulmonary Vein
Aorta

Question 3

Function of Vena Cava

Answer 3

Carries deoxygenated blood from body back to heart.

Question 4

Function of Pulmonary Artery

Answer 4

Carries deoxygenated blood from heart to lungs

Question 5

Function of Pulmonary Vein

Answer 5

Carries oxygenated blood from lungs to heart

Question 6

Function of Aorta

Answer 6

Carries oxygenated blood from heart to body

Question 7

Describe the main stages of diastole (relaxation)

Answer 7

Walls of atria and ventricles relax
Blood flows through atria and into ventricle
AV valves open
Semi Lunar valves shut

Question 8

Describe the main stages of Atrial Systole (contraction)

Answer 8

Walls of atria contract
AV valves open
Blood flows through AV valve into ventricle
SemiLunar valves shut

Question 9

Describe the main stages of Ventricular Systole (contraction)

Answer 9

Walls of ventricles contract
SemiLunar valves open
Blood flows through SemiLunar valves into arteries
AV valves shut

Question 10

Explain why the AV valves are open during atrial systole

Answer 10

The pressure in the atria is higher than the pressure in the ventricles.
The AV valves are forced open

Question 11

Explain why the AV valves are closed during ventricular systole

Answer 11

The pressure in the ventricles is higher than the pressure in the atria.
The AV valves are forced closed.

Question 12

Describe how the heart beat is regulated and controlled

Answer 12

The sino atrial node (SAN) send out a wave of excitation.
This cause the cardiac muscle in the walls of the atria to contract
The wave of excitation hits the atrio ventricular node (AVN)
The wave of excitation is delayed, to allow time for the blood to flow out of the atria
The bundle of His carries the wave of excitation down the septum
The wave of excitation travels up the Purkyne tissue
The ventricles contract bottom to top, to ensure all the blood is pushed upwards into the arteries