3.6.4.1 Homeostasis and negative feedback

Question 1

What is negative feedback?

Answer 1

When a change causes a response that leads to a reduction in that change (return to optimum)

Question 2

Describe the sequence of events that occur during a response to a stimulus (both hormonal and nervous)

Answer 2

Stimulus->Receptor->Coordinator->Effector->Response

Question 3

Define homeostasis.

Answer 3

The maintenance of a constant internal environment.

Question 4

To what are we referring when we say that homeostasis maintain our ‘internal environment’?

Answer 4

The tissue fluids.

Question 5

Which conditions are maintained by homeostasis?

Answer 5

1. Temperature
2. Blood/tissue fluid water potential
3. Blood glucose concentration

Question 6

What is positive feedback? (give an example)

Answer 6

When a change leads to a response that leads to the amplification of that change.
Eg. childbirth, the initial contractions trigger more and stronger contractions.

Question 7

Does homeostasis involve positive feedback?

Answer 7

NO

Question 8

Why is it important to maintain a stable internal temperature?

Answer 8

● Enzymes have optimum temperature
Above this and they denature
Below this they don’t have enough kinetic energy to function