Intro to homeostasis

Homeostasis

The body's ability to maintain a stable internal environment despite changes in external environment.

Stimulus response model

Describes how a system responds to a stimulus

Positive feedback system

the response increases the stimulus

Negative Feedback system

response counters stimulus returning it to the state it was in before stimulus occurred.

Stimulus response model system

Stimulus, Receptor, Modulator, Effector, Response

What is stimulus?

an event/molecule that can initiate a response.

What is a receptor?

a structure that detects a signal or external change (usually a protein)

What is a modulator?

location where info from receptors is sent and compared to a set point and molecules altering the function of the effector are released.

What is an effector?

a molecule, cell or organ that responds to a signal and produces a response

What is the response?

the action of a cell, organ or organism caused by a stimulus

Why is often more than one negative feedback loop required?

negative feedback loops often overcompensate to reduce the stimulus, another one may be needed to increase the stimulus again to return the body to set point.

Set point

the ideal or optimal value for a particular physiological variable eg. internal body temp

Why is maintenance of homeostasis important?

allows organisms to survive and thrive by ensuring that internal bodily systems have the necessary conditions to carry out their vital function

How is set point and homeostasis related?

set point helps to maintain homeostasis by providing an optimal value for the modulator to compare the current conditions/stimulus to. This leads to either an increase or decrease in a stimulus response.

What stimulus response model is used in the maintenance of homeostasis?

Negative feedback loop

Why does homeostasis use negative feedback loops?

negative feedback loops maintain a stable internal environment by returning the system to a set point.

Why doesn't homeostasis use a positive feedback loop?

positive feedback loops amplify the stimulus, taking the bodily system further away from the set point. it often leads to instability.