L18. Homeostasis

Question 1

What does homeostasis refer to?

Answer 1

Arrangements to restore the normal state once it has been disturbed.

Question 2

What is negative feedback control? Give an example.

Answer 2

Alters the variable to COUNTERACT the change.

eg if body temperature decreases, negative feedback acts to increase body temperature.

Question 3

What is feed forward control? Give an example.

Answer 3

Alters behaviour BEFORE there is an obvious error signal.

eg stop eating before “full”.

Question 4

What is positive feedback control? Give an example.

Answer 4

Alters variable levels to INCREASE the change
A small change causes a much bigger change
eg blood clotting

Question 5

Describe osmosis in a hypotonic solution.

Answer 5

Lower concentration outside the dell

Water moves in

Question 6

Describe osmosis in an isotonic solution.

Answer 6

Same concentration inside and outside the cell

No net change in cell volume.

Question 7

Describe osmosis in a hypertonic solution.

Answer 7

Higher concentration outside the cell

Water moves out of the cell