Homeostasis & Negative Feedback

What is homeostasis?

The regulation of the internal conditions of a cell or organism to maintain optimum conditions for function, in response to internal and external changes.

Why is homeostasis important?

It maintains optimum conditions for enzyme action and all cell functions.

Which internal conditions are controlled by homeostasis?

Blood glucose concentration, body temperature and water levels.

What is a stimulus?

A change in the internal or external environment.

What is a receptor?

A cell that detects a stimulus (change in the environment).

What is a coordination centre?

It receives and processes information from receptors. Examples include the brain, spinal cord and pancreas.

What is an effector?

A muscle or gland that brings about a response which restores optimum conditions.

What are the three main parts of an automatic control system?

Receptors → coordination centre → effectors.

What is negative feedback?

If a condition changes from its optimum level, responses are triggered that counteract the change and return the condition towards its optimum level.

How does negative feedback maintain optimum conditions?

A change is detected by receptors, information is processed by a coordination centre, and effectors produce a response that counteracts the change.