Homeostasis

Homeostasis
-is a process of maintaining constant physical and chemical factors within an internal environment to ensure survival of body cells.
-Internal environment refers to environment surrounding the cell which consist of tissue fluid(interstitial fluid), plasma and lymph.
-Factors involved in homeostasis are:
i)Physical factors- body temp, blood pressure, osmotic pressure.
ii)Chemical factors- blood pH value, glucose and mineral(salt), concentration of blood.
-The organ involved in homeostasis are:
>Receptors- special cell that can detect changes in certain factor and an impulse is generated to be sent to central nervous system (usually the brain)
>Control centre- control centre that receives impulses from receptors, coordinates them and sends action signals (impulses or hormones) to the effectors or target organs.
>Effectors- muscle or gland that corrects the changes in the internal environment after receiving impulse from the control center.

Importance of Homeostasis
-Life of organism becomes less dependent on external environment because the organism is able to control changes in its internal environment to compensate for changes in external conditions.
-Ensures an optimum internal environment for cells to function, the organism to survive and reproduce efficiently.
-Enables biological systems to function efficiently and smoothly with minimum wastage of energy.
-The organism can live in wider range of habitats because the species can live in areas with variable conditions.
-The organism can increase or decrease the metabolic rate of its body according to its requirements.

Negative feedback mechanism
-Regulatory mechanism that's used to restore the body to its original constant state after it has been affected by any disturbance.
-If the physiological parameter were raised/lowered, a process would take place to reduce/increase the parameter involved.

Positive feedback mechanism
-Mechanism that is seldom used as it creates further extreme to the changes that has occurred.
-If a physiological parameter were increased/lowered, positive feedback would further increase/lower the factor.
-Eg: Action of hormone.