Home / iGCSE Biology (0610)-9.3 Blood vessels – iGCSE Style Questions Paper 4

iGCSE Biology (0610)-9.3 Blood vessels – iGCSE Style Questions Paper 4

IGCSE Biology (0610) Practice Questions Paper 4 - All Chapters
Question

(a) Fig. 1.1 is a simplified diagram of the circulatory system in humans.

Human circulatory system diagram

(i) State the letter from Fig. 1.1 that represents the blood vessel that contains blood with the highest concentration of oxygen.
(ii) State the letter from Fig. 1.1 that represents the hepatic portal vein.
(iii) State all the letters from Fig. 1.1 that represent arteries.

(iv) Explain the importance of the part labelled Y in Fig. 1.1.
(v) State the evidence from Fig. 1.1 that the diagram shows a double circulation system.

(b) Fig. 1.2 shows the pressure of blood flowing through different blood vessels as it travels around the body. (Venules are narrow vessels that connect capillaries to veins.)

Blood pressure graph

(i) Blood vessels X in Fig. 1.2 supply blood to skin-surface capillaries and have a role in maintaining a constant internal temperature.
State the name of the blood vessels that are represented by the letter X in Fig. 1.2.
(ii) Explain reasons for the changes in pressure seen in the arteries in Fig. 1.2

(iii) Using the information in Fig. 1.2, explain the structural adaptations of arteries and veins

▶️ Answer/Explanation
Solution

(a)(i) B

Explanation: B represents the pulmonary vein which carries oxygenated blood from the lungs to the heart, having the highest O2 concentration (95-100% saturation).

(a)(ii) C

Explanation: The hepatic portal vein (C) carries nutrient-rich blood from the digestive organs to the liver for processing before reaching systemic circulation.

(a)(iii) A, D, E

Explanation: These are arteries: A (aorta), D (renal artery), and E (hepatic artery). Arteries carry blood away from the heart, distinguished by their thick muscular walls.

(a)(iv)

Explanation: Y is the septum that prevents mixing of oxygenated (left side) and deoxygenated blood (right side), ensuring efficient oxygenation of tissues.

(a)(v)

Explanation: Double circulation is evident as blood passes through the heart twice – pulmonary circuit (heart→lungs→heart) and systemic circuit (heart→body→heart).

(b)(i) Arterioles

Explanation: Arterioles (X) are small diameter vessels that regulate blood flow to capillaries, controlling heat exchange at skin surface.

(b)(ii)

Explanation: Pressure fluctuates due to ventricular contraction (systole = high pressure) and relaxation (diastole = lower pressure). The elastic arteries dampen these pulses.

(b)(iii)

Artery Adaptations:
• Thick muscular walls withstand high pressure (~120 mmHg)
• Elastic fibers allow expansion/recoil to maintain flow
• Narrow lumen maintains velocity

Vein Adaptations:
• Large lumen reduces resistance to low-pressure flow (~10 mmHg)
• Valves prevent backflow against gravity
• Thin walls allow compression by skeletal muscles

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