Pancreatic endocrinology Flashcards
What do alpha cells secrete?
glucagon
What do beta cells secrete?
insulin
What is the most common cell in the pancreatic islets?
beta
What do delta cells secrete?
somatostatin
What does local insulin release inhibit?
glucagon
Which hormone decreases glycogenolysis and gluconeogensis?
insulin
Which hormone increases glucose uptake in tissues?
insulin
Which hormone increases hepatic glucose output?
glucagon
Describe the mechanism of insulin release
Increased blood glucose Increased glucose in beta cell Increased rate of glucose metabolism Increased ATP Closes K+ channels Opens Ca2+ channels Insulin is released
What is proinsulin a precursor for?
insulin
Describe biphasic insulin release?
first phase- rapid release of stored product
second phase- slower release of newly synthesied product
Describe how insulin causes an increase in glucose uptake in cells?
Insulin binds to insulin receptors
Intracellular signalling cascade
GLUT4 vesicle mobalisation
Glucose entry into cell via GLUT4
Where are the primary glucose sensors?
pancreatic islets
What does low blood glucose stimulate the release of?
glucagon
What does high blood glucose inhibit the release of?
glucagon
How does glucagon act on the liver?
converts glycogen into glucose (glycogenolysis)
forms glucose from lactic acid and amino acids (gluconeogensis)
What does high blood glucose stimulate the release of?
insulin
Describe the actions of insulin
accelerates facillitated diffusion of glucose into cells
speeds up conversion of glucose into glycogen
Increases uptake of amino acids and protein synthesis
Speeds up synthesis of fatty acids
Slows glycogenolysis
Slows gluconeogensis
What do low blood glucose levels inhibit the release of?
insulin
What disease is characterised by hyperglycaemia ?
diabetes mellitus
