7.3 - Circulatory System Of A Mammal

Question 1

Why does the efficient supply of materials over a large distance require a mass transport system?

Answer 1

Because diffusion is not fast enough for large distances

Question 2

A transport system is required for what?

Answer 2

To take materials from cells to exchange surfaces and from exchange surfaces to cells, they are also needed to be transported between different parts of the organisms

Question 3

What are the main features of a transport system?

Answer 3

1. A suitable medium in which to carry materials, e.g blood.
2. A form of mass transport in which the transport medium is moved around in bulk over large distances - more rapid than diffusion
3. A closed system of tubular vessels that contains the transport medium and forms a branching network to distribute to all part of the organism
4. A mechanism for moving the transported medium within the vessels - this requires a pressure difference between one part of the system and another

Question 4

What is the mechanism for moving the transport medium in the vessels in amimals and plants?

Answer 4

Animals - uses muscular contraction either of the body muscles or the heart
Plants - rely on natural, passive processes such as the evaporation of water

Question 5

Do mammels have a open or close circulatory system?

Answer 5

Closed

Question 6

Why do mammels have a close circulatory system?

Answer 6

When blood is passes through the lungs, its pressure is reduced. If it where to pass immediately to the rest of the body its low pressure would make circulation very slow. Blood is therefore returned to the heart to boost its pressure before getting circulated around to the rest of the tissues

Question 7

Why is it nessasery that mammels get substances delivered to the rest of the body quickly?

Answer 7

Because they have a high body temperature and hence a high rate of metabolism