Bio 2B Regulation and Maintenance of Homeostasis

regulation

the process of controlling body systems to maintain ideal function and homeostasis (depends on nervous and endocrine systems)

stimulus

a detectable change (physical or chemical) in the environment (external or internal) of an organism that results in some activity in response (ex. body temp. rising)

control center

brain/gland that senses stimulus message and decides on a response; send a message to an effector by nerve signal/hormone message (ex. brain senses and sends message to sweat glands)

effector

organ/gland/muscle that performs an action (ex. sweat glands start sweating)

response

any behavior of a living organism that results from an external or internal stimulus (ex. body temp. returning to normal)

positive feedback mechanism

rare; stimulus leads to a response that INCREASES stimulus (ex. sneezing, childbirth)

negative feedback mechanism

common; stimulus leads to response that negates stimulus (ex. body temp. regulation)

hormone

chemical substances that act like messenger molecules in the body