Biology Homeostasis

All about Homeostasis topic

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  • Created by: arun
  • Created on: 19-10-10 03:51
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Biology 4 Revision Notes
Homeostasis means the maintenance of a constant internal environment.
The body needs to keep certain things the same to stay healthy. There are six things that need
to be controlled:
1) Body Temperature
2) Water levels - if not, too much water could enter/leave cells by osmosis
3) Ion content
4) Urea
5) Carbon dioxide
6) Blood Pressure
7) Glucose Levels
From Mrs. GRENCH ­ Movement, Respiration, Sensitivity, Growth, Reproduction,
Excretion, Nourishment, Cells, and Homeostasis ­ all organisms are sensitive to their
Living organisms can detect changes in their environment and co ­ ordinate their
responses to enhance survival.
Plants do it without a nervous system.
Keyword ­ Stimuli ­ Change in an animal's surroundings ­ this can be internal or
Detection ­ H20 ­ Amount, direction
Light ­ brightness, wave length, duration, direction
Positive = grow towards
Negative = grow away
Photo = Light
Hydro = water
Geo = gravity
E.g. ­ `phototropism ­ positive = response towards light e.g., shoot tips
`Negative geotropism'= response away from gravity e.g. ­ stem / shoot tips.
These responses are a result of directional growth i.e. a relatively slow response caused
by growing towards/away ­ Eucalyptus, Sunflower, touch me not, Venus flytrap.
The thermoregulatory centre is the part of the brain that monitors and controls body
The pancreas meanwhile monitors and controls blood glucose concentration.
It produces a hormone called insulin that reduces blood glucose levels.
Diabetes is a disease which can be caused by insufficient insulin.

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The Eye
Skin…read more

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The skin is a barrier to the outside world against bacteria etc.
The skin is also very sensitive to we can feel things
The skin's main function is temperature control.…read more

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