Biology - AQA - Unit 3 - Blood Vessels

Blood Vessels

There are three different types of blood vessel:

• Arteries carry blood away from the heart.
• Capillaries are involved in the exchange of substances at the tissues.
• Veins carry blood to the heart.

Arteries

• They have thick walls composed largely of muscle and elastic tissue. 
• The heart pumps the blood out at high pressure. Contraction of the ventricle forces blood into the artery causing it to expand, you can feel this when you take your pulse. The artery then recoils as the ventricle relaxes and this keeps the blood pressure high.
• The muscle tissue makes them strong.
• The elastic fibres allow them to stretch and…