6.4.1 Princibles Of Homeostasis

Question 1

Describe homeostasis in mammals

Answer 1

Maintenance of a stable internal environment with restricted limits

By physiological control systems that normally involve negative feedback

E.g. core temp, blood glucose

Question 2

Importance of maintains core temp

Answer 2

Is temp is to high:
-H bonds in teritary structure in enzymes break
-enzymes denature, active stores change shape, substances can’t bind
-no enzyme-substrate complexes formed

If temp is low:
-less kinetic energy so fewer enzyme-substrate complexes formed

Question 3

Importance of maintain blood Ph

Answer 3

Above/below optimum pH:
-H bonds break
-enzymes denature
-no enzyme-substrate complexes

Question 4

Importance of maintaining blood glucose

Answer 4

To low(hypoglycaemia):
-not enough glucose for respiration
-less ATP produced
-active transport can’t happen(cell dies)

To high(hyperglycaemia)
-water potential of blood decreases
-water lost from tissues to blood (osmosis)
-kidneys can’t absorb all glucose so more water lost in urine causing dehydration

Question 5

Roles of negative feedback in homeostasis

Answer 5

-receptors detect change from optimum
-effectors respond to counter act change
-retrying to optimum levels

Question 6

Positive feedback

Answer 6

Receptors detect change from normal
-effects respond to amplify change
-producing greater greater deviations from normal

NOT in homeostasis
E.g. contractions in childbirth