Mass transport in animals -

Question 1

What type of circulatory system do mammals have?

Answer 1

Closed double circulatory system - blood passes through heart twice for every circuit around body.

Question 2

Describe the general pattern of blood circulation in a mammal.

Answer 2

1. Deoxygenated blood in right side of heart pumped to lungs ; oxygenated returns to left side.
2. Oxygenated blood in left side of the heart is pumped to the rest of the body ; deoxygenated returns to the right.

Question 3

Suggest the importance of a double circulatory system

Answer 3

Prevents mixing of oxygenated / deoxygenated blood
- so blood pumped to body is fully saturated with oxygen for aerobic respiration.
Blood can be pumped to body at a higher pressure ( after being lower from lungs )
- Substances taken to / removed from body cells quicker / more efficiently.

Question 4

What are the 4 blood vessels that enter and leave the heart and lungs.

Answer 4

Vena cava
Pulmonary artery
Aorta
Pulmonary vein.

Question 5

Function of vena cava ?

Answer 5

Transports deoxygenated blood from respiration body tissue —> heart.

Question 6

Function of pulmonary artery ?

Answer 6

transports deoxygenated blood from heart to the lungs

Question 7

Function of pulmonary vein ?

Answer 7

Transports oxygenated blood from the heart to the lungs

Question 8

Function of aorta?

Answer 8

Transports oxygenated blood from heart into respiring tissues.

Question 9

Name the blood vessels entering and leaving the kidney.

Answer 9

Renal arteries, Renal veins.

Question 10

Function of renal arteries ?

Answer 10

Oxygenated blood into kidneys.

Question 11

Function of renal veins ?

Answer 11

Deoxygenated blood to vena cava from kidneys.

Question 12

Name the blood vessels that carry oxygenated blood to the heart muscle.

Answer 12

Coronary arteries - located on surface area of the heart, branching from aorta.

Question 13

Suggest why the wall of the left ventricle is thicker than that of the right.

Answer 13

• Thicker muscle to contract with greater force
• To generate higher pressure to pump blood around entire body.

Question 14

What are the 3 stages of the cardiac cycle.

Answer 14

Atrial systole, Ventricular systole, Diastole.

Question 15

Describe the stage of the atrial systole.

Answer 15

Atria contract - volume decreases, pressure increases.
- The atrioventricular valves open when pressure in atria exceeds pressure in ventricles..
- Semilunar valves remain shut as pressure in arteries exceeds pressure in ventricles.
- So blood is pushed into ventricles.

Question 16

Describe the stage of ventricular systole?

Answer 16

Ventricles contract - volume decreases, pressure increases.
- Atrioventricular valves shut when pressure in ventricles exceeds pressure in atria .
- Semilunar valves open when pressure in ventricles exceeds pressure in arteries.
- So blood pushed out of heart through arteries

Question 17

Describe the stage of diastole ?

Answer 17

Atria and ventricles relax - volume increases and pressure decreases.
- Semilunar valves shut when pressure in arteries exceeds pressure in ventricles.
- Atrioventricular valves open when pressure in atria exceeds pressure in the ventricles.
So blood fills atria via veins and flows passively to ventricles.