Homeostasis - GCSE Biology

Maintaining a constant internal environment
Conditions that must be controlled:
1. Core body temperature
2. Water content
3. Carbon dioxide level
4. Blood sugar level
Hormones are responsible for homeostasis
1. Proteins that act as chemical messengers
2. Secreted by glands
3. Transported in the bloodstream
4. Only affect the function of particular songs
5. Activated cells are called 'target' cells
6. Cells have a chemical receptor that responds to the hormone
Thermoregulation
1. Thermoregulatory centre in the hypothalamus senses the temperature of the blood flowing through it
2. Hypothalamus triggers responses to heat loss/gain
3. Hypothalamus reverts body temp. back towards the normal
4. This system is called negative feedback
Water content regulation
1. Controlled by loss of ions from:
  1. The lungs through exhalation
  2. The skin through sweating
  3. Urination - the kidneys

Resource summary

	Created by Beth Coiley over 9 years ago