Loading…
Loading…
GCSE Biology · key term
A very narrow blood vessel with a wall one cell thick, where substances are exchanged between blood and surrounding tissues.
Used by AQA, Edexcel and OCR
Specification 4.2.2.2 · Paper 1
A microscopic blood vessel with a wall one cell thick, across which substances are exchanged between the blood and tissues.
Revise: Blood Vessel Structure and Rate of FlowOne type of vessel could not perform all three jobs efficiently, so the circulatory system contains arteries, capillaries and veins. Their structures differ because the pressure and purpose of the blood flow differ in each part of the system.
Specification 8.3, 8.7 · Paper 2
A tiny blood vessel with a thin wall that allows substances to pass between the blood and surrounding tissues.
Revise: AlveoliEach alveolus is closely surrounded by capillaries carrying blood. This puts air and blood next to one another without mixing them: gases pass through the thin walls between them.
Specification B2.2c, B2.2d · Paper 1 (Foundation), Paper 3 (Higher)
A very small blood vessel through which substances are exchanged between the blood and surrounding tissues.
Revise: Human circulatory systemArteries carry blood away from the heart. They divide into progressively smaller vessels and eventually lead to networks of capillaries within organs. Capillaries are the exchange vessels: dissolved substances move between the blood and nearby cells across very short distances.
A microscopic blood vessel with a wall one cell thick, across which substances are exchanged between blood and tissues.
Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
A tiny blood vessel where substances can move between the blood and surrounding tissues or air in the lungs.
Revise: Circulatory SystemThere it passes through tiny vessels called capillaries, which lie beside the air-filled alveoli. Oxygen diffuses from the air into the blood, while carbon dioxide diffuses from the blood into the air to be breathed out. Blood returns from the lungs to the left side of the heart.
A very narrow blood vessel where substances are exchanged between the blood and surrounding tissues.
For each vessel, link a named structural feature directly to its function: for example, a capillary wall is one cell thick, so the diffusion distance is short.
Remember that “one cell thick” describes a capillary wall, not the width of the entire capillary.
When explaining an adaptation, link the feature to its function: for example, a capillary’s one-cell-thick wall gives substances a short distance to diffuse.
Create a free account to read GCSE Biology revision notes for your exam board and track your progress.