Sesh 10- Endocrine Pancreas and Diabetes Mellitus Flashcards
What are the cells that perform the endocrine function of the pancreas called?
Islets of Langerhans
What are the 3 main peptide hormones made by the pancreas?
Insulin
Glucagon
Somatostatin
Which specific cell types within the Islets of Langerhans are insulin and glucagon secreted by?
Insulin- beta cells
Glucagon- alpha cells
What are the 2 main actions of glucagon on the liver?
- Glycogenolysis
- Gluconeogenesis
Are insulins actions anabolic or catabolic?
Anabolic
What is the renal threshold for glucose reabsorption?
10 mmol/L
Is less than this in pregnancy, and increased in the elderly
How is insulin made?
As preproinsulin- cleaved in ER to proinsulin
-Cleaved further in golgi–> Insulin + C peptide= stored separately in vesicles
What receptors in pancreatic beta cells allow sensing of plasma glucose?
GLUT2
Which channels in pancreatic beta cells shut, causing membrane depolarisation and insulin secretion?
K-ATP channels- inhibited by ATP (increases when intracellular glucose increases)
What type of receptor is the insulin receptor?
Tyrosine Kinase Receptor
How does insulin increase glucose uptake into cells?
Binds cell surface insulin receptor to cause GLUT4 translocation
What are the 4 main broad actions of insulin?
- Increases intracellular glucose uptake
- Increases glycogenesis in liver
- Increases protein synthesis
- Increases TG storage
On what organ does glucagon mainly have its effects?
Liver
What stimulus increases BOTH insulin and glucagon secretion?
Increase in amino acids
NB: Insulin increases protein synthesis and glucagon increases a.a. metabolism
Symptoms of hypoglycaemia are similar to being in what state?
Drunk
e.g. slurred speech, staggering, loss of consciousness
