The conditions inside the body must be controlled within narrow limits. This is called homeostasis. These conditions include water content, ion content, body temperature and blood glucose concentration.
The thermoregulatory centre is the part of the brain that monitors and controls body temperature. 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.
Waste products must be removed from the body. If they are not, they will increase in concentration and may interfere with chemical reactions or damage cells. Waste products that must be removed include carbon dioxide and urea.
|Waste product||Why is it produced?||How is it removed?|
|carbon dioxide||it is a product of aerobic respiration||through the lungs when we breathe out|
|urea||it is produced in the liver when excess amino acids are broken down||the kidneys remove it from the blood and make urine, which is stored in the bladder temporarily|
Water enters the body through food and drink. It is also a product of aerobic respiration in cells. If the amount of water in the body is wrong, cells can be damaged because too much water enters or leaves them. The animation shows how the amount of water lost as urine is controlled. Note that you do not need to know any details of this for the examination.