Homeostasis unit1a biology

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Homeostasis means keeping the conditions inside the body constant. Conditions include temperature, blood suagar, water and carbon dioxide. Having a 'constant internal environment'.

The body temperature is normally 37 degrees Celcius if the temperature drops or rises by 3 degrees you will become ill.

Homeostasis is maintaining a constant internal environment

Conditions in your body need to be kept steady so that cells can function properly. This involves balancing imputs with outputs.

  • levels of CO2 - respiration in cells constantly produces CO2, which you need to get rid of
  • Levels of oxygen - you need to replace the oxygen that your cells use up in respiration
  • Water content - you need to keep a balance between the water you gain in drink, food and from respiration and the water you lose by pee, sweat and when breathing out.
  • Body Temperature - you need to get rid of excess body heat when you are hot but retain heat when the environment is cold.

Water is Lost from the Body in Various Ways

Water is taken into the body as food and drink and is lost from the body:
-- through the skin and sweat
-- via the lungs in breath
-- via the kidneys in urine

On  a cold day or when you are not exercising, you don't exercise as much so you'll produce more urine, which will be pale.
On a hot day or when you are exercising you are sweating a lot so you will produce less urine but this will be concerntrated ( a deeper colour). You will also lose more water through breathing when you exercise becuase you breathe faster.

Negative Feedback Helps things Steady

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