metabollic homeostasis and starvation

Question 1

how many phases of glucose homeostasis are there

Answer 1

5

Question 2

what happens during phase 1

Answer 2

the well fed state
glucose is provided by dietary carbohydrates

Question 3

what 3 things occur during phase 2

Answer 3

hepatic glycogenolysis maintains blood glucose concentration
glycogen supply decreases
hepatic gluconeogenesis from lactate, glycerol and alanine increases

Question 4

what happens during phase 3

Answer 4

about 24 hours later glycogen stores are exhausted
gluconeogenesis is now the major source of blood glucose

Question 5

what happens during phase 4

Answer 5

after several days the dependance on hepatic gluconeogenesis declines
ketone bodies concentration in blood is high enough to enter the brain
renal gluconeogenesis also becomes significant

Question 6

what happens during phase 5

Answer 6

occurs after prolonged starvation
energy needs of almost all tissues met by fatty acid oxidation or ketone body oxidation
as long as ketone body concentration are high there is a reduced need for muscle waste

Question 7

what maintains ketone body concentration

Answer 7

body fat