Key learning points

1. Blood contains blood cells suspended in a fluid called plasma.
2. Red blood cells transport oxygen, and have a structure adapted to carry as much oxygen as possible.
3. Plasma transports water, glucose and other nutrients, and waste products including carbon dioxide and urea.
4. Arteries carry blood away from the heart; capillaries carry blood to/from cells; veins carry blood back to the heart.
5. Arteries, capillaries and veins have structures adapted to their functions, including different vessel walls and valves.

Keywords

• Red blood cell - A blood cell that uses haemoglobin to bind and transport oxygen.

• Plasma - The fluid of the blood which carries blood cells and other substances.

• Artery - Large blood vessels with thicker walls which transport blood away from the heart.

• Vein - Large blood vessel which transports blood towards the heart.

• Capillary - Narrow blood vessel which allows exchange of substances between tissue and blood.

Common misconception