3.6.4.1 Homeostasis and negative feedback Flashcards Preview

SHHS - Science - NEW AQA A-Level Biology (Year 2) > 3.6.4.1 Homeostasis and negative feedback > Flashcards

Flashcards in 3.6.4.1 Homeostasis and negative feedback Deck (8)
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1
Q

What is negative feedback?

A

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

2
Q

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

A

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

3
Q

Define homeostasis.

A

The maintenance of a constant internal environment.

4
Q

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

A

The tissue fluids.

5
Q

Which conditions are maintained by homeostasis?

A
  1. Temperature
  2. Blood/tissue fluid water potential
  3. Blood glucose concentration
6
Q

What is positive feedback? (give an example)

A

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.

7
Q

Does homeostasis involve positive feedback?

A

NO

8
Q

Why is it important to maintain a stable internal temperature?

A

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