1.6 Types, Structure and Function of Blood Vessels

Question 1

What are arteries and their job?

Answer 1

Arteries are blood vessels that carry blood away from the heart. With the exception of the pulmonary arteries, they carry oxygen-rich blood.

Question 2

What is the structure of arteries?

Answer 2

• Their walls contain several layers of thick elastic fibres and muscle. This helps to regulate blood flow.
• Arteries branch into smaller distributive arteries and eventually arterioles, which are very small arteries that lead to capillary beds in the tissue.

Question 3

Give an example of an artery.

Answer 3

The aorta is the largest artery in the body and it’s thick elastic walls deal with the surge of blood leaving the heart.

Question 4

How do arteries maintain blood flow?

Answer 4

As blood enters, they expand and recoil.

Question 5

What are capillaries?

Answer 5

A capillary is a microscopic tube with walls only one cell thick covered by a sieve-like basement membrane.

Question 6

What do capillaries do?

Answer 6

They supply the tissues with oxygen and nutrients whilst removing waste products such as carbon dioxide.

Question 7

What are veins?

Answer 7

Plasma leaves the capillaries and enters small blood vessels known as venules that join together to form veins.

Question 8

What is the structure of veins?

Answer 8

• They have a large internal diameter will walls much thinner than arteries that contain less muscle and elastic tissue.
• To ensure blood flows in the right direction, veins have valves throughout their length that prevent back flow.

Question 9

What do veins do?

Answer 9

Blood flowing in the veins is not under pressure, and with the exception of pulmonary veins, they carry deoxygenated blood back to the heart.

Question 10

What can blockages in the veins cause?

Answer 10

Varicose veins.