Physiology: The Exocrine Pancreas Flashcards
How does insulin lower blood glucose?
Drives anabolic pathways in target tissue to promote storage of nutrients
What is the function of glucagon?
Glucagon acts on the liver to promote hepatic glucose production, raising blood glucose
What do β-cells secrete?
Insulin
What is the function of GLP-1?
GLP-1 increases glucose-induced insulin release by β-cells, promotes beta cell proliferation and suppress glucagon secretion at depolarising glucose concentrations
Describe the action of ⍺-cells during high blood glucose levels
At high glucose, glucose uptake and metabolism are high
KATP channel closed, cell depolarised
SGLT2 glucose transporters contribute to sodium ion influx
Voltage-gated sodium channels and voltage gated calcium channels close and glucagon is not exocytosed
What do ε-cells secrete?
Ghrelin
What is the incretin effect?
Greater increase in insulin production in response to oral glucose than in response to IV glucose
Describe the action of ⍺-cells during low blood glucose levels
At low glucose, glucose uptake and metabolism are low
KATP channels open, voltage-gated sodium channels (NaV) contributes to action potentials
Voltage gated calcium channels (CaV) enable calcium influx which triggers glucagon exocytosis
Why do incretin drugs never cause hypoglycaemia?
Act via the amplifying pathway - augment insulin secretion when the pathway is triggered, so no action when there is no glucose
What do δ-cells secrete?
Somatostatin
What do ⍺-cells secrete?
Glucagon
How does the ⍺-cell contribute to hyperglycaemia in T2DM?
Glucagon secretion is elevated in the fed state in T2DM
What is somatostatin 14?
Secreted from δ-cells in response to nutrient or hormonal stimulation when suppression of β-cell and ⍺-cell function is needed (paracrine regulation)
Where are δ-cells and PP cells located within the islets of Langerhans?
Near the periphery
Insulin secretion defects are a feature of which type of diabetes?
T2DM
