Controlling Internal Conditions

The temperature inside our bodies must stay close to 37 degrees centigrade. This is the temperature that many of the chemical reactions that happen inside our bodies to keep us alive works best. If our body temperature went more than a couple of degrees above or below this we would be in a lot of danger.

This is just one thing that must be kept roughly the same inside our bodies. the others we need to know are listed below. So how does our body keep them the same?

Sensors on the surface and inside the body are continually sending information to the brain. The brain may then send signals to muscles or to glands which have the power to adjust the situation if it is less than ideal.

e.g. if we are too hot

sweat	take off clothing	fan yourself	drink more

if we are too cold

shiver	put on clothing	get goose bumps	go indoors

Do sports drinks work?
one of the things that has to stay the same inside our bodies is the concentration of the ions in solution, in our cells and in our blood.

When we sweat and have a wee our bodies lose ions which much be replaced or we may become ill. People doing sport often drink special drinks, instead of water, which are supposed to replace ions as well as provide energy. Do you know the names of any isotonic sports drinks? It is debatable whether these drinks actually work or if they are just a clever way of making money.

REMEMBER

Internal conditions which are controlled include

the water content of the body
water leaves the body via the lungs when we breathe out
via the skin when we sweat
excess water is lost via the kidneys in the urine

the ion content of the body
ions are lost via the skin when we sweat
excess ions are lost via the kidneys in the urine

temperature
to maintain the temperature at which enzymes work best

blood sugar levels
to provide the cells with a constant supply of energy.