Homeostasis

Unit 4

Homeostasis

Any process that organisms use to maintain stable internal physiological conditions necessary for survival.

Dynamic equilibrium

This constant ebb and flow of physiological responses to change ensures that conditions remain stable within acceptable fluctuating ranges.

For example, a person’s body temperature may safely fluctuate daily within a range of 36°C to 37.8°C.

What are the two types of homeostatic control mechanisms, and how do they respond to change?

1. negative and positive feedback.

2. must contain a monitor, a coordinating centre, and a regulator.

What a motor?

senses the change and “reports” it to the coordinating centre

whats a coordinating centre

conveys the information to a specific regulator

Regulator

Responds to the change.

Eg. special sensory cells called thermoreceptors detect changes in external environmental temperatures.

negative feedback

→ A mechanism that opposes physiological change by countering it with a response that tries to restore physiological conditions to their original state.

→This mechanism tries to eliminate small effects by countering them with other physiological responses. (think opposites)

Positive feedback

→ A mechanism that amplifies the effect of the stimulus on the steady state, often driving the effect through to completion. This mechanism makes small effects greater and greater.

Eg. giving birth to baby.