Exchange Surfaces

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  • Created by: amina96
  • Created on: 23-02-14 08:26
Preview of Exchange Surfaces

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! ! amina96
Most gas exchanges... !
[ Note: I will be using this symbol ^, to explain the dash point above, and ^^
to explain the point (^) ]!
1) Have a large surface area.
- the many alveoli provide a large surface, so a faster rate of dif-
2) Are thin
-generally, 1 layer of epithelial cells!
^ This would mean that there is a short diffusion passage
across the gas exchange surface (in other words, a shorter dis-
tance the gases would have to travel), and so a faster rate of
** (also alveolar epithelium and capillary endothelium, are
1 cell thick, so shorter diffusion pathway = faster rate of dif-
3) Have a steep concentration gradient of O and CO
- this is maintained across the exchange surface --> so a faster
rate of diffusion.
** (alveoli have a good blood supply from the capillaries --
as they constantly take away O and bring more CO...
maintaining concentration gradient)!
** by breathing in+out --> air ----> conc gradient high!
in alveoli !
is refreshed!

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Page 2

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Gas Exchange - in the alveoli...…read more

Page 3

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Goblet cells:
What does it do?
- It secretes mucus!
^ The mucus traps the microorganisms + dust particles
from the inhaled stopping them reaching the alveoli!
Smooth muscle:!
- found in the walls of the trachea, bronchi and bronchioles!
What does it do?!
- During exercise, the smooth muscle relaxes, making the
tubes wider. This would then cause less resistance to air-
flow & air would be able to move in/out of the lungs more
easily.…read more

Page 4

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Distribution of features in the mammalian gaseous
exchange system...…read more


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