ANSWER KEY
1. A
2. C
3. C
4. B
5. B
6. B
7. C
8. D
9. C
10. A
11. B
12. D
13. B
14. A
15. D
16. C
17. C
18. C
19. B
20. A
21. A
22. A
23. C
24. B
25. D
26. A
27. C
28. D
29. C
30. B
31. D
32. C
33. C
34. A
35. C
36. B
37. C
38. C
39. B
40. C
41. D
42. C
43. SAnode, right atrium
b) The AV node
stimulates the Purkinje
fibres; This causes the
ventricles to contract.
44. A
45. C
46. B
47. B
48. A
49. D
50. Artery: is thick-walled with elastic tissue to be able to withstand the forces of blood pressure. Semi-lunar valve: has
cusps (flaps) which open in one direction only in order to prevent back flow. Capillary: is thin-walled in order to
facilitate the exchange of materials
51. Oxygen-oxyhemaglobin; hydrogen ions - reduced haemoglobin; carbon dioxide- carbaminohemoglobin
52. Artery b) • maintains blood pressure • carries blood away from the heart • carries nutrients and oxygen to the
tissues • controls amount of blood going to various parts of the body
53. U,Z,W,X
b) Name: oval opening
Function: Allows blood to move from the right to the
left atrium, bypassing the pulmonary circuit.
Name: arterial duct
Function: Allows blood to move from the pulmonary
artery and the aorta, bypassing the pulmonary circuit.
Name: umbilical arteries
Function: Take blood containing wastes to the placenta.
Name: umbilical vein
Function: Brings nutrient-rich blood from the placenta.
Name: venous duct
Function: Allows blood to flow from the umbilical vein
to the inferior vena cava.
Name: umbilical cord
Function: Carries O2 / nutrients from the placenta;
carries wastes to the placenta.
54. a) White blood cells produce antibodies that inactivate the antigen.• White blood cells phagocytize the antigen.
b) • Heart rate increases resulting in higher blood pressure.• Arterioles constrict resulting in higher blood pressure.
c) Heart rate increases to raise blood pressure
d) Platelets release a clotting protein to help seal the wound.
55. - The pulmonary vein returns blood from the lungs to the heart and therefore contains a higher concentration of
oxygen and a lower concentration of carbon dioxide. The pulmonary artery carries blood, which has returned from
the systemic circulation, from the heart to the lungs, and therefore contains a higher concentration of carbon dioxide
and a lower concentration of oxygen.
- The blood in the posterior vena cava has picked up carbon dioxide and dropped off oxygen at the tissues.The blood in
the aorta has picked up oxygen and dropped off carbon dioxide at the lungs.
56. X: • The right ventricle has blood with a higher concentration of carbon dioxide (carbaminohemoglobin, bicarbonate
ions, reduced hemoglobin) and a lower concentration of oxygen. (1 mark)
Y:• The left ventricle has blood with a lower concentration of carbon dioxide (carbaminohemoglobin, bicarbonate ions,
reduced hemoglobin) and a higher concentration of oxygen. (1 mark)
b) • The left ventricle is thicker-walled and more muscular (1 mark) to contract and send blood with increased pressure
throughout the body because the blood has a greater distance to cover than blood leaving the right ventricle (1 mark).
57. X: jugular vein; • to carry blood from the head to the anterior (superior) vena cava Y: inferior vena cava; • to carry
blood from the legs and lower body to the heart
b) i) • It is between the right and left atria; to allow blood to bypass the lungs
ii) Blood low in oxygen from the right side of the heart would mix with oxygenated blood from the left side of the heart.
58. • The lymphatic capillaries pick up excess tissue fluid and return it to the blood system.
• The lymph nodes purify the lymph of any infectious organisms or debris through the action of white blood cells.
• The lymph capillaries (lacteals) absorb fats in the intestinal villi and transport them to the blood stream.
• The lymphocytes produce antibodies.
• The spleen purifies the blood.
• Red bone marrow produces red and white blood cells.
• Produces histamine as part of the inflammatory reaction.
• Spleen acts as a blood reservoir.
• Fights infection.
59. SA node: in upper wall of RA. Function: Sends nerve impulses to the AV node; acts as a pacemaker; causes both
atria to contract; initiates the heartbeat
Purkinje fibres: throughout muscle tissue surrounding both ventricles; Function: deliver impulse from AV node to
walls of ventricles; causes ventricles to contract
60. a) • to act as a buffer
• to carry oxygen / form oxyhemoglobin
• to carry hydrogen ions / form reduced hemoglobin
• to carry carbon dioxide / form carbaminohemoglobin
• to increase the pH of the blood by picking up hydrogen ions
b) • The pulmonary artery will have more reduced hemoglobin than the pulmonary vein. / The pulmonary vein will have
less reduced hemoglobin than the pulmonary artery.
• The pulmonary artery will have more carbaminohemoglobin than the pulmonary vein. / The pulmonary vein will have
less carbaminohemoglobin than the pulmonary artery.
• The pulmonary vein will have more oxyhemoglobin and the pulmonary artery will have less oxyhemoglobin.
61. a)RBC:• Carry oxygen.
• Act as a buffer.
• Carry hydrogen ions.
• Carry carbon dioxide.
WBC: • Fight infections.
• Produce antibodies.
• Phagocytize.
PLATELETS: • Initiate blood clotting.
• Form a temporary clot.
b) Red blood cells are produced in the bone marrow