Chapter 8

Question 1

Why are specialized transport systems needed? (5)

Answer 1

• Metabolic demands of multicellular animals is high.
• SA:V Ratio gets smaller as they get larger. Increased diffusion distances.
• Molecules such as hormones and enzymes may be present in 1 place but needed in another.
• Food needs to be transported from digestion organ to the needed cells.
• Waste products of metabolism need to be removed from cells and transported to the excretory organs.

Question 2

Does an open circulatory system carry oxygen and c02

Answer 2

No, Carries food and nitrogenous waste products.

Question 3

In a closed circulatory system, how can the amount of blood being transferred to different tissues.

Answer 3

They an be controlled by vasoconstriction and vasodilation.

Question 4

Name 3 components of blood vessels and explain them.

Answer 4

Elastic Fibres - Composed of elastin and can stretch and recoil, providing vessel walls with flexibility.

Smooth muscle - Contracts or relaxes, changes the size of the lumen

Collagen - Provides structural support to maintain the shape and volume of the vessel