Principles of Homeostasis

Question 1

What is homeostasis?

Answer 1

Regulation of internal conditions of an organism for optimal functioning in response to internal and external changes.

Question 2

What is homeostasis dependent upon?

Answer 2

Many variables being kept within certain pre-set limits, including:

• Body temperature
• Fluid balance
• pH of extracellular fluid
• pH of blood
• Blood concentrations of sodium, potassium and calcium ions
• Blood sugar levels

Question 3

What are receptors?

Answer 3

Animals external environment is not stable, which affects their internal environment, so their body is not a the right conditions for optimal functioning. Therefore, receptors detect changes in internal conditions
effectors can generate a response.

Question 4

What is negative feedback?

Answer 4

• Any change in internal environment is reversed and returned to normal state
• Most common type of feedback in body
• E.g. blood glucose, temperature control

Question 5

What is positive feedback?

Answer 5

• Change in internal environment causes effector to be stimulated and reinforce change and amplify response
• Comparatively few examples in body
• E.g. blood clotting, oxytocin in childbirth