Circulatory system of mammal

Question 1

Why is the transport system more essential in larger organisms?

Answer 1

Larger organisms have evolved into larger and more complex structures, the tissues and organs they are made have become more specialised so transport system is more essential for them.

Question 2

What does the transport system depend on?

Answer 2

• SA:V
• How active the organism is
  Lower the SA:V and more active the organism, greater the need for a specialised transport system with a pump.

Question 3

What are the common features of a transport system?

Answer 3

• A suitable medium to carry the material e.g. blood. This is usually liquid-based because substances can be dissolved into it and can be moved around easily but it can also be a gas e.g. air as it can be breathed in and out.
• The transport medium must be moved around in bulk over large distances.
• A closed system of tubular vessels which contains the transport medium and branched network to distribute it to all parts of the organism.
• A mechanism to move the transport medium within vessels, this requires a pressure difference between one part of the system and the other.

Question 4

What are the 2 ways of a transport system?

Answer 4

• Animals use a muscular contraction, either body muscles or specialised pumping organ e.g. heart.
• Plant relies on natural, passive processes e.g. evaporation of water.

Question 5

What does a closed double circulatory system mean?

Answer 5

Blood is passed through the heart 2 times in each complete circuit of the body.
This is because when the blood passes through the lungs, the pressure is reduced if it were to pass straight away to the rest of the body, the low pressure would make the circulation very slow. So the blood returns to the heart to boost its pressure before being circulated to the rest of the tissues so substances can be delivered at a faster rate which is needed for mammals that has a high body temperature and hence a high rate of metabolic rate.

Question 6

What are the 3 types of blood vessels?

Answer 6

Arteries
Veins
Capillaries

Question 7

Give names of different blood vessels and their role.

Answer 7

1) Pulmonary artery - carries blood from the heart to the lungs.
2) Pulmonary vein - carries blood from the lungs to the heart.
3) Aorta - carries blood from the heart to the rest of the body.
4) Vena cava - carries blood from the body to the heart.
5) Renal artery - carries blood from the body to the kidneys.
6) Renal vein - carries blood from the kidneys into the vena cava.