Exchange & Transport - part 1
- Created by: r.chowwww
- Created on: 06-12-21 17:19
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- Exchange
- Exchanging materials
- o -> alveoli in lungs b/c it's needed for respiration
- CO2 -> alveoli in lungs b/c it's a waste product of metabolism
- Water -> nephrons in kidney b/c it's needed for cells to function properly
- Dissolved food molecules -> sm intestine b/c it's needed for respiration
- Mineral ions -> sm intestine b/c it's needed for cells to function properly
- Urea -> nephrons in kidney b/c it's a waste product of metabolism
- As organisms get bigger, their SA:Volume gets smaller. This means they can't rely on diffusion. They need to have specialised exchange surfaces & transport systems.
- Alveoli
- Adaptations
- Alveoli r adapted for gas exchange by diffusion b/w air in lungs & blood in capillaries
- Lungs
- O diffuses from the air in2 the blood.
- CO2 diffuses from the blood in2 the air.
- Millions of tiny alveoli = large SA for diffusion of gases
- Each alveolus is closely associated w/ a capillary. walls r 1 cell thick, minimising diffusion distance
- Ventilation of alveolus (breathing) & continual blood flow thru capillaries maintains high concentration gradient, to maximise rate of diffusion
- Adaptations
- Rate of diffusion
- Effectiveness of an exchange surface increases w/:
- increase in SA e.g. alveoli
- a shorter distance for diffusion e.g. surfaces r 1 cell thick
- maintenance of a high concentration gradient e.g. efficient blood supply, lungs r ventilated
- Fick's law
- rate of diffusion = SA x concentration diff / thickness of membrane
- For the rate to be high, the SA & concentration diff need to be high but the thickness of membrane needs to be low
- Effectiveness of an exchange surface increases w/:
- Blood
- Untitled
- Blood vessels
- Exchanging materials
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