Homeostasis

1. Homeostasis How the human organism responds to its environment using homeostatic mechanisms

2. What is homeostasis? • homeo = same or unchanged • Greek homoio-, combining form of hómoios similar, like • stasis = to remain still or steady • Greek, from sta- base of histanai 'to stand‘ - a period or state of inactivity or equilibrium • involves a control system by which an animal maintains a stable internal environment, despite fluctuations in their environment.

3. Objectives of this unit: To find out how homeostasis works: • To explore how and why the human animal maintains a stable internal environment, • including how a specific disruption results in responses within a control system to re-establish a stable internal environment

4. and... • the adaptive advantage for humans of their various homeostatic control systems • the biochemical and biophysical processes underpinning each mechanism • (e.g.equilibrium reactions, changes in membrane permeability, metabolic pathways).

5. and... • What happens when the control system breaks down completely due to extreme environmental factors? • ie when the control system cannot re-establish the homeostatic balance

6. Humans have control systems that regulate: • body temperature • blood pressure • osmotic balance • level of blood glucose • levels and balance of respiratory gases in tissues.

7. …environmental factors? • What environmental factors might affect the homeostatic control system? • External influences such as: • exposure to extreme environmental conditions , • disease or infection, • drugs or toxins, • Internal influences such as: • genetic conditions or metabolic disorders

8. The big ideas we’ll cover: • purpose of the system • components of the system • mechanism of the system (how it responds to being disrupted within a normal range of environmental fluctuations) • possible effect of extreme disruption to the system by internal or external influences, resulting in its breakdown.