HOMEOSTASIS AND FEEDBACK CONTROL

pp 1041-1042

• Homeostasis: maintaining stable internal environment

• Bringing body back to normal• The sympathetic and parasympathetic

divisions of the autonomic system function in opposition to each other for “flight or fight” response

HOMEOSTASIS

• Last step of the series controls the first

FEEDBACK MECHANISMS

• Negative feedback: the product (response) stops production of the initial stimulus

EX. Thermoregulation (sweating and shivering)

NEGATIVE FEEDBACK

POSITIVE FEEDBACK

• The product stimulates production of the initial stimulating substance or action (i.e. contractions during labor)