Transport in animals
- Created by: geburdon99
- Created on: 21-10-15 22:26
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- Transport in animals
- Factors that affect the need for a transport system.
- Size
- Once an organism has several layers of cells, any oxygen or nutrients diffusing in from the outside will be used up by the outer layers of cells.
- Surface-area-to-volume ratio
- Small animals have a larger surface area to volume ratio than large animals.
- The surface area-to-volume ratio is affected by the animal's shape.
- Level of activity
- Releasing energy from food by respiration requires oxygen.
- If the organism is fairly active, its cells will need good supplies of nutrients and oxygen, to supply the energy for movement.
- Size
- Features of a good transport system.
- A fluid to carry nutrients and oxygen around the body.
- A pump to create pressure that will push the fluid around the body.
- Exchange surfaces that enable oxygen and nutrients to enter the blood and for waste products to be removed.
- Tubes or vessels to carry the blood.
- Two circuits - one to pick up oxygen and another to deliver oxygen to the tissues.
- Single and double circulatory systems.
- Single circulatory systems
- Occur in Fish.
- Heart, Gills, Body, Heart
- Double circulatory systems
- Occur in mammals.
- Pulmonary circulation is when one circuit carries blood to the lungs to pick up oxygen.
- Systemic circulation is when one circuit carries the oxygen and nutrients around the body to the tissues.
- Heart, body, heart, lungs, heart.
- Single circulatory systems
- Advantages of a double circulation system.
- In the Fish single circulatory system.
- The blood pressure is reduced as blood passes through the tiny capillaries of the gills.
- This means the blood won't flow very quickly to the rest of the body
- This limits the rate at which oxygen and nutrients are delivered to respiring tissues.
- This means the blood won't flow very quickly to the rest of the body
- The blood pressure is reduced as blood passes through the tiny capillaries of the gills.
- In the mammal double circulatory system.
- The heart can increase the pressure of the blood after it has passed through the lungs, so blood flows more quickly to the tissues.
- The systematic circulation can carry blood at a higher pressure than the pulmonary circulation.
- The blood pressure must not be too high in the pulmonary circulation, otherwise it may damage the delicate capillaries in the lungs.
- The systematic circulation can carry blood at a higher pressure than the pulmonary circulation.
- The heart can increase the pressure of the blood after it has passed through the lungs, so blood flows more quickly to the tissues.
- In the Fish single circulatory system.
- Factors that affect the need for a transport system.
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