biochemistry of glucose and insulin Flashcards
what is hyperglycaemia
fasting blood glucose >7mM
this person would be diabetic
explain glucose homeostasis
what cells are responsible for releasing glucagon
pancreatic alpha cells
what cells are responsible for releasing insulin and also making it
pancreatic beta cells
they should only do this in response to blood glucose rising above 5mM
what is the first organ to be affected in hypoglycaemia
brain ie confusion
<4mM
what is a healthy fasting blood sugar
4-6mM
(6-7mM = pre-diabetes)
why is insulin efficient
accurate sensing of blood glucose changes
the correct amount of insulin is released
counter-regulatory mechanisms to protect against hypos
what are the cells of the pancreatic islets
what is the part of insulin that is cleaved off
C-peptide
how is insulin secreted
REFER TO SHEET
glucose enters B cells through the GLUT2 glucose transporter and is phosphorylated by glucokinase
*glucokinases Km fro glucose lies in physiological range of concentrations
> changes in glucose concentrations can drastically change glucokinase activity
pathophysiology of T1DM
beta cells are mostly lost > autoimmune destruction
> beta cells lose the ability to sense changes in glucose due to hyperglycaemia taking glucose concentration outwith the Km of glucokinase
T2DM pathophys
beta cell function declines
they try to compensate for the hyperglycaemia > and so presents with hyperinsulinemia
