Controlling Our Internal Environment (Homeostasis) :D

Homeostasis can be defined as the maintenance of a *stable internal environment through negative feedback despite fluctuations in the external environment.

((*stable = conditions fluctuate within a narrow range about a set point))

Homeostasis controls:

• Temperature
• PH
• Ion concentration in the blood
• Glucose concentration in the blood

• Homeostasis provides a constant internal environment and independence from fluctuating external conditions.
• Features that influence internal environment have a set level ((called the 'norm')).
• Any changes from the norm are called 'deviation'.
• Negative feedback is caused by deviation from the norm; it results in a return to the norm.
• When the body experiences changes in the external environment, the homeostatic system evens out the variations experienced by the body in a number of ways:
  • The liver can store or release glucose
  • Blood is kept at a constant, ideal state; glucose concentration remains at 80mg/cm3
  • Tissue fluid surrounding the cells has constant ideal conditions and contains the optimum glucose concentration for respiration to occur