Bio C9

Question 1

1. What is the circulatory system?

Answer 1

A series of blood vessels with a pump and valves to prevent backflow

Question 2

2. Describe a single circulatory system

Answer 2

The blood only passes through the heart once for each full circuit of the body
Heart → Gills → Body

Question 3

3. Describe a double circulatory system

Answer 3

The blood passes through the heart twice per circuit
Heart → Body → Heart → Lungs

Question 4

4. What is the advantage of a double circulatory system?

Answer 4

Double circulatory systems can maintain a higher blood pressure which increases the speed at which the blood flows so nutrients can be delivered and waste can be removed more
quickly

Question 5

5. Identify the structures of the heart labelled in the diagram below

Answer 5

Question 6

6. Name this artery and state its purpose

Answer 6

It is the coronary artery and it supplies the heart muscle with blood

Question 7

7. What is the name of the wall that separates the right and left sides of the heart?

Answer 7

The septum

Question 8

8. Why is the wall of the left ventricle thicker than the wall of the right ventricle?

Answer 8

The left ventricle has to pump blood a further distance around the whole body
so the blood needs to be under a higher pressure

Question 9

9. Why do the ventricles have thicker walls than the atria?

Answer 9

The ventricles need to pump blood at a higher pressure to pump it out and round the body and to the lungs whereas the atria only need to pump the blood into the ventricles (a shorter distance) so do not need to generate as high of a pressure

Question 10

10. What is the difference in function between veins, arteries and capillaries?

Answer 10

Arteries carry blood away from the heart
Veins carry blood towards (into) the heart
Capillaries flow close to tissues for exchange

Question 11

11. Why is the septum important?

Answer 11

It separates the oxygenated blood from the deoxygenated blood

Question 12

12. Draw the direction of blood flow through the heart on the diagram below

Answer 12

Question 13

13. Describe the blood flow through the right side of the heart

Answer 13

• Deoxygenated blood flows into the right atrium from the vena cava
• This blood passes through the atrioventricular valve (tricuspid) into the right ventricle
• The blood is then pumped out of the heart to the lungs through the right semi-lunar valve and into the pulmonary artery

Question 14

14. Describe the blood flow through the left side of the heart

Answer 14

• Blood enters into the left atrium from the pulmonary vein
• The blood is then pumped through the atrioventricular valve (bicuspid valve) into the left ventricle
• The blood is then pumped out through the left semilunar valve and into the aorta

Question 15

15. Give 3 ways of measuring the activity of the heart

Answer 15

ECG
Pulse rate
Listening to the sounds of the valves

Question 16

16. Explain the effect of physical exercise on heart rate

Answer 16

Physical exercise increases heart rate

Question 17

17. What is coronary heart disease (CHD)?

Answer 17

When the artery providing the heart tissue with blood (the coronary artery) becomes blocked

Question 18

18. How can coronary heart disease be prevented by altering lifestyle choices?

Answer 18

• Exercise regularly
• Control diet: Eat less saturated fats
• Stop smoking/drinking wine

Question 19

19. Describe the structure of arteries, capillaries, and veins

Answer 19

Arteries have thick walls made of muscle and elastic tissue and a small lumen to transport blood under high pressure
Capillaries have thin walls about one cell thick to allow for the easy exchange of substances at the tissues.
Veins have less muscle and elastic tissue than arteries and they have a larger lumen as the blood is at lower pressure, they also have valves to prevent backflow

Question 20

20. The names of the main arteries for organs in the body.

Answer 20

Pulmonary artery
Hepatic artery
Renal artery
Aorta

Question 21

21. The names of the main veins.

Answer 21

Pulmonary vein
Hepatic vein
Hepatic portal vein
Renal vein
Vena cava

Question 22

22. Name 4 components of the blood

Answer 22

• Red blood cells
• White blood cells
• Platelets
• Plasma

Question 23

23. Name 2 types of white blood cell

Answer 23

Phagocyte
Lymphocyte

Question 24

24. What is the function of platelets?

Answer 24

They are used in forming blood clots

Question 25

25. What is the purpose of blood clotting?

Answer 25

• Preventing excess blood loss
• Preventing the entry of pathogens through wounds

Question 26

26. Describe the process of blood clotting？

Answer 26

When a blood vessel is broken, the platelets stick together to form clumps. Meanwhile the platelets release a substance that makes the fibrinogen change into an insoluble protein called fibrin. This forms fibres, which pile up on top of each other to make a mesh-like structure that helps to seal the wound. Red blood cells get trapped in the mesh. The fibres, the trapped red blood cells and the clumps of platelets form a blood clot

Question 27

27. What is the function of red blood cells?

Answer 27

Transporting oxygen to tissues using haemoglobin

Question 28

28. State 2 functions of white blood cells？

Answer 28

• Phagocytosis (engulfing pathogens)
• Producing specific antibodies

Question 29

29. What is the function of plasma?

Answer 29

Transporting: nutrients like glucose, amino acids, and mineral ions
Hormones such as adrenaline and insulin
Various proteins (including fibrinogen and antibodies)
waste products, including carbon dioxide and urea