1.1 The Heart and Blood Vessels

Question 1

Arteries (4)

Answer 1

• Narrow lumen.
• Thicker walls.
• More elastic fibres, collage, smooth muscle.
• No valves.

Question 2

Veins (4)

Answer 2

• Wide lumen
  
  • Thinner walls
  • Less collagen, elastic fibres and smooth muscle.
  • Valves.

Question 3

Capillaries (4)

Answer 3

• Capillaries join small arteries (arterioles) and Small veins (venules)
• One cell thick walls (called endothelial cells)
• Lumen is the same width as one RBC
• No muscle or elastic tissue.

Question 4

Why is the lumen on the capillary the same width as one RBC?

Answer 4

More of RBC in contact with wall, therefore smaller diffusion distance

Question 5

What is the importance of Smooth Muscle?

Answer 5

Walls constrict and dilate.

Question 6

What is the importance of Elastic Fibres?

Answer 6

Stretch and recoil.

Question 7

What is the importance of blood vessels containing Collagen (Tough fibrous protein)?

Answer 7

Strong and durable.

Question 8

How is the Heart muscle supplied blood?

Answer 8

Heart muscle is supplied with blood through two vessels called the coronary arteries because the heart is unable to use any of the blood inside it’s pumping chambers directly.

Question 9

What is the importance of a network of capillaries?

Answer 9

Network of capillaries lies close to every cell which ensures rapid diffusion between blood and surrounding cells.