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exchanging substances (gills have a large surface area for gas exchange…
exchanging substances
exchange substances with their environment
1)cells can use diffusion to take in substances they need and get rid of waste products
oxygen and carbon dioxide are transferred between cells and the environment during gas exchange
in human urea diffusion from cells into the blood plasma for removal from the body by the kidneys.
2)its easy to exchange substances with its environment depending on surface area to volume ratio.
multicellular organisms need exchange surface
multicellular organism have a smaller surface area compared to their volume not enough substances diffuse from their outside surface to supply their entire volume this means they need some sort of exchange surface.
exchanged surface are adapted to maximise effectiveness
they have a large surface area so lots of a substance can diffuse at once
exchange surface in animals have lots of blood vessels to get stuff into and out of the blood quickly
they have a thin membrane so substance only have a short distance to diffuse
gas exchange surfaces in animals are often ventilated too-air moves in and out
in single cell organisms gases and dissolves substances can diffuse directly into the cell across the cell membrane its because they have a large surface area compared to their volume so enough substance can be exchanged across the membrane to supply the volume of the cell
gas exchange happens in the lungs
to do this the lungs contain millions of little air sacs called alveoli where gas exchange takes place
the alveoli are specialised to maximise the diffusion of the oxygen and co2 they have:
a moist lining for dissolving gases
very thin walls
an enormous surface area (about 75 m2 in humans )
a good blood supply
the job of the lungs is to transfer oxygen to the blood and to remove waste carbon dioxide from it
the villi provides a really big surface area
they increase te surface aarea in a big way so that digested food is absorbed much more quickly into the blood
they have
a single layer of surface cells
a very good blood supply to assists quick absorptions
the inside of the small intestine is covered in millions and millions of these tint little projections called villi
the structure of leaves lets gases diffuse in and out of cells
2)oxygen and water vapour also diffuse out through the stomata
3)the size of the stomata is controlled by guard cells these close the stomata if the plants is losing water faster than it is being replaced by roots without these guard cells the plant would soon wilt
1) the underneath of the leaf is an exchange surface its covered in biddy little holes called stomata which the carbon dioxide diffuses in through
4)flattened shape of the leaf increases the area of this exchange surface so that its more effective
carbon dioxide diffuses unto the air spaces within the leaf then it diffuses into the cells
5)the walls of the cell inside the leaf from another exchange surface the air spaces inside the leaf increases the area of this surface so there's more chance for carbon dioxide to get into the cells.
gills have a large surface area for gas exchange
5)the LAMELLA have lots of blood capillaries to speed up diffusion
4)the gill filaments are covered in lots of tiny structures called lamellae which increases the surface area even more
3) each gill is made of lots of tin plates called gill filaments which give a big surface area from exchange of gases
2)water enters the fish through its mouth and passes out through the gills as this happens oxygen diffuses from the water into the blood in the gills and carbon dioxide diffuses from the blood into the water
1)the gills are the gas exchanged surface in fish
6)have thin surface layer of cells to minimise the distance that the gas has to diffuse
7)blood flows through the lamellae in one direction and water flows over in the opposite direction this maintains a large concentration gradient between the water and the blood
8) the concentration of oxygen in the water is always higher than that in the blood so as much oxygen as possible diffusion from the water into te blood