Mini Test: Heart and cardiac cycle

Question 1

Three reasons why organisms need transport systems

Answer 1

• Higher metabolic rate
• small SA : V
• Cells too deep in body / too large diffusion dfistance

Question 2

state 4 functions of blood vessels attached to heart

Answer 2

Vena Cava- carries deoxy blood from body to heart
Pulmnonary artery- deoxy blood from heart to lungs
pulmonary vein- carry oxygen blood from lungs to heart
Aorta- oxygen blood from heart to body

Question 3

describe main stages of diastole

Answer 3

• walls of atria and ventricles relax
• Blood flows through atria and into ventricle
• AV valves open
• semi lunar valves shut

Question 4

Describe main stages of atrial systole

Answer 4

• walls of atria contact
• AV valves open
• Blood flows through AV valves into ventricle
• semi lunar valves shut ( ventricles relax)

Question 5

Describe main stages of ventricular systole

Answer 5

• walls of ventricles contract
• semi lunar valves open
• blood flows through semi lunar valves into arteries
• AV valves shut

Question 6

Explain why AV valves ate open during atrial systole

Answer 6

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

Question 7

Explain why AV valves are closed during ventricular systole

Answer 7

• Pressure in ventricles higher than pressure in atria

- AV valves forced closed

Question 8

Describe how the heart beat is regulated and controlled

Answer 8

• The sino-atrial node send out wave of excitation
• this cause the cardiac muscle in walls of atria to contract
• The wave of excitation hits the atrio ventricular node
• The wave of excitation is delayed (0.1s), allow blood to flow out of atria
• The bundle of His carries wave of excitation down the septum
• Wave of excitation travels up purkyne tissue
• ventricles contract bottom to top, to ensure all the blood is pushed upwards into the arteries