Homeostasis

Question 1

why is homeostasis important

Answer 1

cells function most effectively at optimal conditions. Operates to control changes in the cellular environment

Question 2

what are the two main mechanisms of homeostasis control

Answer 2

1 - feedback control

2 - feed forward control

Question 3

negative feedback control

Answer 3

a change in a variable activates mechanisms that alter the level of that variable to counteract the change
widely used mechanism e.g body temp drops so hypothalamus initiates shivering to warm body

Question 4

feed forward control

Answer 4

involves altering a behaviour before there is an obvious error signal
e.g stop eating before ‘full’

Question 5

positive feedback control

Answer 5

a change in a variable activates mechanisms to alter the level of that variable so as to increase the change
NOT used in homeostasis
e.g blood clotting

Question 6

hypertonic

Answer 6

higher omsotic pressure therefore cells shrink until concs equal

Question 7

isotonic

Answer 7

same conc inside and out

Question 8

hypotonic

Answer 8

lower osmotic pressure therefore cells swell as solution rushes in