Biology Unit 1 Exam- Control in the Human Body

The body has many internal conditions that need controlling, the body does this in different ways. Some examples of controlled internal conditions are:

• the water content of the body- water leaves the body via the lungs when we breathe out, and via the skin when we sweat to cool us down, other excess water is lost via the kidneys in urine
• the  ion content of the body- ions are lost via the skin when we sweat and excess ions are lost via the kidneys in urine
• temperature- to maintain the temperature at which enzymes work best
• blood sugar levels- to provide the cells with a constant supply of energy

Many processes in the body are controlled by substances called hormones. Hormonesare secreted by glands and are usually transported to their target organs by the bloodstream.

Homones regulate the functions of many organs and cells. An example of this is the monthly release of an egg from a woman's ovaries and the changes in the thickness of the lining in her womb. All these…