Water is taken into the body through food and drink.
It leaves the body in the following ways:
- 1) Through skin as SWEAT
- 2) Via the lungs as BREATH
- 3) Via the kidneys as URINE
HOT DAY or EXERCISING
- Sweat a lot
- Produce less urine to conseve water but it is concentrated so darker in colour
- Lose more water through your breath when exercising
COLD DAY or NOT EXERCISING
- Don't sweat as much
- Produce more urine, which will be pale because the waste in the urine has become more diluted
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WHEN YOU'RE TOO HOT
- Lots of sweat is produced - when it evapourates, it transfers heat from your skin to the environment, cooling you down
- VASODILATION - blood vessels close to the surface of the skin widen. This allows more blood to flow to the surface so it can radiate heat out into the surroundings.
- Hairs lie flat
WHEN YOU'RE TOO COLD
- Very little sweat is produced
- VASOCONSTRICTION - blood vessels close to the surface of the skin constrict so less heat can be transferred from the blood to the surroundings
- Hairs stand on end to trap an insulating layer of air to keep you warm
- You shiver and the movement generates heat in your muscles. Exercise does the same.
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