In: Anatomy and Physiology
Discuss homeostasis within the context of positive and negative feedback. What type of feedback is predominantly used? Why? Be able to give examples of both types of feedback.
Homeostasis refers to the maintenance of constant internal environment of the body. Homeostasis is necessary to maintain the normal physiological functions of the body.
Homeostasis is achieved by feedback mechanism(feedback signals). Feedback mechanism is a process in which some of the output signal of the system is fed back to the input. There are two types of feedback mechanism in the body:
a. Negative feedback : occurs to reduce the change or output.
b. Positive feedback : occurs to increase the change or output.
NEGATIVE FEEDBACK MECHANISM is predominantly used by the body to maintain homeostasis.
Examples:
a. Negative feedback mechanism :
Secretion of thyroxine (when thyroxine level increases in blood,negative feedback inhibits the secretion of TSH from pituitary gland leading to decreased secretion of thyroxine).
Maintenance of water balance.
Blood sugar regulation.
b. Positive feedback mechanism :
Parturition (induces labor by the secretion of oxytocin hormone)
Blood clotting.