Arteries
- There are three main types of blood vessel:
- Arteries- carry blood away from the heart
- Veins- carry blood towards the heart
- Capillaries- involved in the exchange of gas of materials with tissues
- Each vessel has a particular function and is specifically adapted to carry out that function efficiently
- There are also smaller vessels, arterioles that branch off from arteries and venules that branch into veins
Arteries carry blood under pressure
- Key features:
- Carry blood at high pressure away from the heart
- Carry oxygenated blood (except the pulmonary artery)
- Have a narrow lumen
- Have thick muscular walls compared to the size of the lumen
- The strong muscular walls contain elastic fibres to allow them to stretch and spring back
- Blood flows through at a fast speed
- The structure of an artery is adapted to its function in the following ways
- Thick muscular walls withstand the high pressure of blood and maintain the blood pressure as it recoils after the blood has passed through
- A narrow lumen also helps to maintain high pressure