7.3 Circulatory system of a mammal

Question 1

What affects whether organisms have specialised transport medium and whether it is circulated by a pump?

Answer 1

SA:Vol
activity of the organisms
lower SA: volume and higher activity
- greater need for specialised system with a pump

Question 2

Features of transport system

Answer 2

• a medium to carry materials
• form of mass transport to move medium
• closed system of vessels to transport medium
• mechanism that moves the medium in vessels

Question 3

why do large organisms have a transport system?

Answer 3

• small SA:vol
• so have specialised exchange surfaces
• it’s required to take substances from the exchange surfaces to all the cells

Question 4

describe the pattern of blood circulation in a mammal

Answer 4

• closed double circulatory system
• deoxygenated blood is pumped to the lungs from the heart
• oxygenated blood is pumped to the rest of the body

Question 5

what mechanisms do humans use in the transport system?

Answer 5

muscular contraction
- by muscles
or
- by specialised pumping organs (the heart)

Question 6

what mechanisms do plants use in the transport system?

Answer 6

natural, passive processes (evaporation of water)
- mechanism that maintains the flow in one direction (vessels)
- a means of controlling flow accordingly
- mechanism for the mass flow of water/gases

Question 7

why is it necessary for humans to have substances delivered quickly?

Answer 7

humans have a high body temperature a
- therefore have a high rate of metabolism