NEGATIVE FEEDBACK MECHANISM and POSITIVE FEEDBACK MECHANISM

(1.1) Negative Feedback Mechanism

-Most systems of the body are regulated by NEGATIVE FEEDBACK MECHANISM, which maintains homeostasis

(1.2) Negative Feedback Mechanism

-The word Negative is used to mean "bad" or undesirable". In this context, the word Negative means to "decrease"

(1.3) Negative Feedback Mechanism

-Negative Feedback is when any deviation from the setpoint is made smaller or is resisted

(1.4) Negative Feedback Mechanism

-Negative Feedback doesn't prevent variation but maintains variation within a normal range

(1.5) Negative Feedback Mechanism

Example: Negative Feedback Mechanism is the maintainance of the normal body temperature

(2) Three Components of Negative Feedback Mechanism

-RECEPTOR, CONTROL CENTER, and EFFECTOR

(3) Receptor

-monitors the value of a variable, such as the body temperature, by detecting stimuli

(4) Control Center

such as the part of the brain that determines the setpoint for the variable, and receives input from the receptor about the variable

(5) Effector

-such as the sweat glands that can change the value of variable when directed by the control center

(6) Stimulus

-a changed variable that initiates a homeostatic mechanism

(7.1) Positive Feedback Mechanism

-Occurs when the initial stimulus further stimulates the response.

(7.2) Positive Feedback Mechanism

-Positive means "Increase"

(7.3) Positive Feedback Mechanism

-is when any deviation from the setpoint becomes even greater.

(7.4) Positive Feedback Mechanism

Example: Childbirth