5.5 Circulatory System 2 - Blood vessels

Question 1

What are the three main types of blood vessel?

Answer 1

• Arteries
• Capillaries
• Veins

Question 2

What do arteries do?

Answer 2

These carry the blood away from the heart.

Question 3

What do capillaries do?

Answer 3

Capillaries carry blood through the body tissues, allowing oxygen, nutrients, and waste products, to be exchanged between tissues and the blood.

Question 4

What do veins do?

Answer 4

These carry the blood to the heart.

Question 5

How are the arteries adapted for their role?

Answer 5

• The heart pumps the blood out at high pressure so the artery walls are strong and elastic. The walls are thick compared to the size of the lumen.
• They contain thick layers of muscle to make them strong, and elastic fibres to allow them to stretch and spring back.

Question 6

What is the lumen?

Answer 6

The hole/space inside a blood vessel

Question 7

How are the capillaries adapted for their role? (3)

Answer 7

• Capillaries are really tiny - too small to see.
• Capillaries carry the blood very close to every cell in the body to exchange substances within them which means they have permeable walls, so substances can diffuse in and out.
• Their walls are usually only one cell thick. This increases the rate of diffusion by decreasing the distance over which it occurs.

Question 8

What do the capillaries supply?

Answer 8

Food and oxygen

Question 9

What do capillaries take away?

Answer 9

Waste, like carbon dioxide

Question 10

What is a network of capillaries in tissues called?

Answer 10

A capillary bed

Question 11

How does a lower blood pressure help the capillaries to carry out their functions?

Answer 11

It gives the blood more time to exchange substances with the tissues.

Question 12

How are the veins adapted for their role? (3)

Answer 12

• The blood is at lower pressure in the veins so the walls don’t need to be as thick as artery walls. They have a thin layer of elastic fibres and smooth muscle.
• They have a bigger lumen than arteries to help the blood flow despite the lower pressure.
• They also have valves to help keep the blood flowing in the right direction.

Question 13

How could you remember that arteries carry blood away from the heart?

Answer 13

‘A for Artery’ and ‘A for Away from the heart’

Question 14

If you consider all the blood vessels inside of a human body, which type of blood vessel accounts for the majority of the cross-sectional area?

Answer 14

Capillaries