integration of metabolism

Question 1

anti-insulin hormones

Answer 1

adrenaline
cortisol
GH

Question 2

endocrine cells of pancreas and proportion of alpha and beta cells

Answer 2

alpha: 60-70%
beta: 30-40%
delta: somatostatin

Question 3

cellular control of insulin secretion

Answer 3

glucose enters cell by GLUT 2-> glucose-6-phosphate by GLUCOKINASE-> ATP produced
aa enters cell-> ATP produced
ATP causes K channels to close-> {K} builds up in cell-> ca channels open-> exocytosis of insulin vesicles

Question 4

processing of insulin prohormone

Answer 4

pro-insulin undergoes proteolysis-> C-peptide + insulin

Question 5

cellular actions of insulin

Answer 5

insulin binds to alpha subunit-> tyrosine kinase-P -> IRS-P -> phosphorylation cascade:
dephosphorylation of glycogen synthase kinase-> glycogen synthase active
translocation of GLUT 4 to membrane
phosphodiesterase-P -> cAmp converted to AMP-> no cAmp-> PKA inhibited-> hormone-sensitive lipase inhibited
OR
tyrosine kinase-P -> RAS-P -> RAF phosphorylates MEK kinase-> MEK-P -> MAPK-P -> transcription factor activated

Question 6

location of GLUT 124; are they insulin dependent?

Answer 6

GLUT 1 (independent) : RBC/brain/pancreas/liver
GLUT 2 (independent): pancreas/liver
GLUT 4 (dependent): muscle/adipose

Question 7

adrenaline vs cortisol

Answer 7

adrenaline (short-term): glycogenolysis/ FA release

cortisol (long term): gluconeogenesis/ FA release/ AA release

Question 8

effects of insulin in fed state on brain

Answer 8

brain takes up glucose via GLUT 1 for TCA

Question 9

effects of insulin in fed state on muscles

Answer 9

aa-> protein

glucose taken up via GLUT 4 -> glycogen

Question 10

effects of insulin in fed state on liver

Answer 10

glucose -> glycogen

glucose-> acetyl coA -> TCA OR FA -> TG-> VLDL (to adipocytes)

Question 11

effects of insulin in fed state on adipose

Answer 11

VLDL -> FA + glycerol by LPL
glucose taken up by GLUT 4-> glycerol
glycerol + FA -> TAG
hormone-sensitive lipase inhibited

Question 12

effects of fed state on RBC

Answer 12

glucose taken up by GLUT 1-> anaerobic respiration-> lactate

Question 13

effects of insulin in fed state on tissues

Answer 13

aa -> protein

Question 14

effects of glucagon in fasting/starving state on brain

Answer 14

KB-> acetyl coA-> TCA

glucose-> TCA

Question 15

effects of glucagon in fasting/starving state on adipose

how does FA travel in blood

Answer 15

TAG-> FA + glycerol by HORMONE SENSITIVE LIPASE

FA travels in blood bound to albumin

Question 16

effects of glucagon in fasting/starving state on liver

Answer 16

glycogen-> glucose
aa/glycerol/lactate-> glucose
FA-> acetyl coA-> TCA; excess become KB

Question 17

effects of glucagon in fasting/starving state on muscle

Answer 17

proteins -> aa

FA (from adipose)-> acetyl CoA -> TCA

Question 18

how the body gets energy in starvation

Answer 18

1. glycogen storage
2. gluconeogenesis (AA/ glycerol/lactate)
3. KB/ FA

Question 19

ketone bodies formed in starvation

Answer 19

acetoacetate

beta- hydroxybutyrate

Question 20

how do ketone bodies conserve muscle tissue

Answer 20

stimulates pancreas to release insulin

limits gluconeogenesis -> less aa + FA release

Question 21

type 1 diabetes features and treatment

Answer 21

autoimmune beta cell destruction
hyperglycaemia + ketoacidosis
insulin injections

Question 22

type 2 diabetes features and treatment

Answer 22

insulin resistance
hyperglycaemia
diet/weight/oral hypoglycaemic agents/ biguanides (increase GLUT 4)/sulphonylureas (improve insulin secretion)

Question 23

complications of diabetes mellitus

Answer 23

microangiopathy (basement membrane of small bv thickens)
retinopathy
nephropathy
neuropathy

Question 24

how does metabolic pattern in uncontrolled diabetes resemble starvation

Answer 24

in starvation-> insulin is low
in diabetes type 1 there is NO insulin
glucagon acts unopposed
KB produced