endocrine pancreas Flashcards
normal range BG
4.2-6.3
hypoglycaemia [BG]
< 3
insulin effect [BG]
lowers it
glucagon effect [BG]
increases it
alpha islet cell
glucagon
beta islet cell
insulin
delta islet cell
somatostatin
F islet cell
pancreatic polypeptide
what is extra glucose stored as
glycogen in liver
TAG in liver and adipose tissue
amino acid uses
make new proteins
excess converted to fat
can be enery source
storage of fatty acids
TAGs in adipose tissue + liver
mechanism control insulin secretion by BG
inc BG –> metabolism increases
ATP increases and Katp channels close
cell depolarises and Ca channels open
Ca entry triggers exocytosis and insulin release
primary action of insulin
bind to tyrosine kinase receptors of insulin-sensitive cells which mobilises GLUT-4 channels to cell membrane
additional actions insulin
- inc glycogen synthesis
- inc amino acid uptake
- inc protein synthesis
- inc TAG synthesis
- permissive effect GH
- promote K+ entry cells
stimuli which inc insulin release
- inc BG
- inc amino acid
- glucagon
- gastrin, CCK
- vagal nerve activity
stimuli which inhibit insulin release
- low BG
- somatostatin
- sympathetic effect
- stress e.g.hypoxia
glucose counter regulatory control system
glucagon
epinephrine
cortisol
GH
actions of glucagon
inc glycogenolysis
inc gluconeogenesis
form ketones
(all result in elevated BG)
stimuli that promote glucagon release
low BG inc amino acid sympathetic effect + epinephrine cortisol stress e.g. hypoxia
effect exercise BG
entry glucose into skeletal muscle inc during exercise (even w no inuslin)
starvation effect BG
adipose tissue broken down and FFA released
excess converted to ketones for brain and muscle
ketoacidosis
FFA build up in plasma and create acidosis
stimuli that inhibit glucagon release
glucose
insulin
free fatty acids + ketones
somatostatin
