Circulatory System
Level 2 Test Paper (Recall & Basic Understanding)
Time Limit: 30 minutes Total Marks: 40
Instructions: Answer all questions. Marks are indicated against each question.
Q1. List the four main components of blood and state one function of each. (4 marks)
Q2. Explain the function of hemoglobin. Include the terms oxyhemoglobin and carbaminohemoglobin in your answer. (4 marks)
Q3. Name the four chambers of the human heart and state which blood vessel carries blood into the right atrium and which carries blood out of the left ventricle. (4 marks)
Q4. Trace the path of a blood cell through the pulmonary circulation, starting and ending at the heart. Write the sequence of structures it passes through. (5 marks)
Q5. Briefly explain the three main phases of the cardiac cycle. (3 marks)
Q6. Describe the role of the SA node and the AV node in the conduction system of the heart. (4 marks)
Q7. Complete the comparison table for arteries, veins, and capillaries: (6 marks)
| Feature | Artery | Vein | Capillary |
|---|---|---|---|
| Wall thickness | ? | ? | ? |
| Valves present? | ? | ? | ? |
| Direction of blood flow | ? | ? | — |
Q8. A person has a blood pressure reading of 120/80 mmHg. (a) What do the two numbers represent? (2 marks) (b) Define blood pressure. (1 mark)
Q9. Complete the following about the ABO and Rh blood group system: (4 marks) (a) Which blood group is the universal donor? (b) Which blood group is the universal recipient? (c) A person with Rh⁺ blood has which antigen present? (d) Which antibodies are present in the plasma of a person with blood group A?
Q10. State any three functions of the lymphatic system. (3 marks)
End of Paper
Answer keyMark scheme & solutions
Q1. (4 marks) — 1 mark each: component + function
- Plasma — liquid part; transports nutrients, hormones, wastes, CO₂. (1)
- Red Blood Cells (RBCs / erythrocytes) — carry oxygen via hemoglobin. (1)
- White Blood Cells (WBCs / leukocytes) — defence/immunity, fight infection. (1)
- Platelets (thrombocytes) — help in blood clotting. (1)
Why: Blood = plasma (~55%) + formed elements (~45%). Each has a distinct role.
Q2. (4 marks)
- Hemoglobin is an iron-containing protein in RBCs. (1)
- It binds oxygen in the lungs to form oxyhemoglobin, transporting O₂ to tissues. (1)
- It carries a portion of CO₂ as carbaminohemoglobin from tissues to lungs. (1)
- Its high affinity for O₂ (and reversible binding) enables efficient loading/unloading. (1)
Q3. (4 marks)
- Four chambers: Right Atrium, Left Atrium, Right Ventricle, Left Ventricle. (2, ½ each)
- Blood enters the right atrium via the vena cava (superior & inferior). (1)
- Blood leaves the left ventricle via the aorta. (1)
Q4. (5 marks) — sequence marks Right ventricle → pulmonary artery → lungs (capillaries where gas exchange occurs) → pulmonary vein → left atrium.
- Right ventricle (1)
- Pulmonary artery (1)
- Lungs/pulmonary capillaries (1)
- Pulmonary vein (1)
- Left atrium (1)
Why: Pulmonary circulation carries deoxygenated blood to lungs and oxygenated blood back to the heart.
Q5. (3 marks) — 1 mark each phase
- Atrial systole — atria contract, pushing blood into ventricles. (1)
- Ventricular systole — ventricles contract, pumping blood into pulmonary artery and aorta. (1)
- Diastole (relaxation) — heart relaxes; chambers fill with blood. (1)
Q6. (4 marks)
- SA node (sinoatrial node) — the "pacemaker"; generates electrical impulses that initiate the heartbeat, causing atria to contract. (2)
- AV node (atrioventricular node) — receives the impulse, delays it briefly (allowing ventricles to fill), then relays it via the Bundle of His/Purkinje fibres to cause ventricular contraction. (2)
Q7. (6 marks) — ½ mark per correct cell
| Feature | Artery | Vein | Capillary |
|---|---|---|---|
| Wall thickness | Thick, muscular/elastic | Thinner | One cell thick |
| Valves present? | No (except at heart) | Yes | No |
| Direction of blood flow | Away from heart | Towards heart | — |
Q8. (3 marks) (a) 120 = systolic pressure (during ventricular contraction); 80 = diastolic pressure (during ventricular relaxation). (2) (b) Blood pressure is the force exerted by circulating blood against the walls of blood vessels (arteries). (1)
Q9. (4 marks) — 1 mark each (a) O (O⁻ specifically) — universal donor. (1) (b) AB (AB⁺ specifically) — universal recipient. (1) (c) Rh antigen (D antigen) present. (1) (d) Anti-B antibodies present in group A plasma. (1)
Q10. (3 marks) — 1 mark each, any three
- Returns excess tissue fluid (lymph) to the bloodstream. (1)
- Absorbs and transports fats/fatty acids from the intestine (via lacteals). (1)
- Produces and houses lymphocytes; fights infection (immunity). (1)
- Filters pathogens via lymph nodes. (1)
[
{"claim":"Human heart has 4 chambers",
"code":"chambers=['RA','LA','RV','LV']; result=(len(chambers)==4)"},
{"claim":"Pulmonary circulation sequence has 5 listed structures",
"code":"seq=['right ventricle','pulmonary artery','lungs','pulmonary vein','left atrium']; result=(len(seq)==5 and seq[0]=='right ventricle' and seq[-1]=='left atrium')"},
{"claim":"BP reading 120/80: systolic > diastolic",
"code":"systolic=120; diastolic=80; result=(systolic>diastolic)"},
{"claim":"Group A plasma contains anti-B antibodies, not anti-A",
"code":"antibodies={'A':'anti-B','B':'anti-A','AB':'none','O':'anti-A and anti-B'}; result=(antibodies['A']=='anti-B')"}
]