Blood Vessels Diagram IGCSE Biology 0610

Blood Vessels Diagram: Arteries, Veins and Capillaries

Biology editorial review is supported by the named review panel. Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.

Key diagram

Arteries have thick muscular walls and a narrow lumen to carry blood at high pressure away from the heart. Veins have thinner walls, a wider lumen and valves to carry blood at low pressure back to the heart. Capillaries have walls one cell thick for efficient exchange.

Blood vessel diagrams are tested both as labelling questions and as comparison questions. Students must draw cross-sections showing the relative wall thickness and lumen size, and explain how each feature links to the vessel's function.

Drawing cross-sections

Draw three circles side by side. For the artery, draw a thick wall with a small central space (narrow lumen). Show the wall with three layers: an outer coat, a thick muscular and elastic middle layer, and a smooth inner lining. For the vein, draw a thinner wall with a larger central space (wider lumen). For the capillary, draw a tiny circle with a wall that is only one cell thick: the lumen is just wide enough for a red blood cell to squeeze through.

Artery adaptations

Arteries carry blood away from the heart at high pressure. The thick muscular wall withstands the high pressure without bursting. The elastic fibres stretch and recoil with each heartbeat, smoothing out the pulsing flow. The narrow lumen maintains the high blood pressure. Arteries have no valves (except the semi-lunar valves at the heart).

Vein adaptations

Veins carry blood back to the heart at low pressure. The thinner wall is sufficient because pressure is lower. The wider lumen reduces resistance to flow. Valves prevent the backflow of blood, ensuring it moves in one direction toward the heart. The squeezing action of surrounding skeletal muscles also helps push blood through veins.

Capillary adaptations

Capillaries are the site of substance exchange between blood and tissues. Their wall is one cell thick, giving a short diffusion distance for oxygen, carbon dioxide, glucose and urea. The narrow lumen forces red blood cells to pass through in single file, slowing blood flow and bringing cells close to the capillary wall. Capillaries form extensive networks, providing a large surface area for exchange.

Label checklist

Check these labels are present and correctly positioned before finishing your drawing.

✓ Artery wall (thick, muscular, elastic)
✓ Artery lumen (narrow)
✓ Vein wall (thinner)
✓ Vein lumen (wider)
✓ Vein valve
✓ Capillary wall (one cell thick)
✓ Capillary lumen (very narrow)

Try a diagram question (2 marks)

Explain why the wall of an artery is thicker than the wall of a vein. [2]

Show the answer and marking guidance

Arteries carry blood at high pressure (from the heart).
The thick muscular and elastic wall withstands this high pressure without bursting.

Original Cambridge-style practice written for this site.

Common diagram mistakes

Check these against your own drawing before moving on.

Drawing the artery with a wider lumen than the vein: arteries have a narrower lumen.
Putting valves in arteries: only veins have valves.
Forgetting to show that the capillary wall is one cell thick.
Saying arteries carry oxygenated blood: the pulmonary artery carries deoxygenated blood.