Blood vessels

Question 1

Describe what an artery is and its role.

Answer 1

• Thick elastic muscular wall that has a small lumen. Elastic fibres provide strength to prevent bursting. Muscles contract after pulse passes. Both tissues result in smooth flow of blood.
• Carries blood away from the heart. The blood’s under high pressure.

Question 2

Describe what a vein is and its role.

Answer 2

• Relatively thin wall that contains valves to stop flowing backwards (backflow). Large lumen. Less muscle and elastic fibres due to low pressure.
• Carries blood towards the heart. Blood’s under low pressure.

Question 3

Describe what a capillary is and its role.

Answer 3

• One cell thick permeable wall. Found in large quantities in organs.
• Allows diffusion of oxygen, carbon dioxide, dissolved food and urea into and out of the blood. Low blood pressure.