glucose homeostasis Flashcards
why is glucose homeostasis important
Neuronal tissue has few carbohydrate reserves and limited capacity to metabolize fat
what does the pancreas do in glucose homeostasis
The pancreas secretes the hormones responsible for regulating blood glucose
Insulin
Glucagon
Hormones found in Islets of Langerhans
what is the pancreas
A triangular gland located behind the stomach
exocrine function of pancreeas
Acinar cells produce an enzyme-rich juice used for digestion.
the endocrine function of the pancreas
islets of Langerhans
what are the 3 cells of islets
Alpha cells produce glucagon
Beta cells produce insulin
Delta cells produce somatostatin
what is the structure of glucagon cells (a-cells) 25%
A 29-amino-acid polypeptide hormone that is a potent hyperglycemic agent
what are the functions of alpha cells
Prevents hypoglycemia
what is the action of glucagon
Its major target is the liver, where it promotes:
Glycogenolysis (the breakdown of glycogen to glucose)
Gluconeogenesis (synthesis of glucose from non-carbs)
Release of glucose into the blood from liver cells
what is structure insulin (beta cells -65%)
51-amino-acid protein consisting of two amino acid chains linked by disulfide bonds.
Synthesized as part of proinsulin and then cleaved by enzymes, releasing functional insulin
what is the function of insulin
Prevents hyperglycaemia (lowers blood glucose levels)
what are the main actions of insulin
- Enhances transport of glucose into cells (puts glucose transporters (GLUT-4) into membrane)
- Liver – glucose uptake and glycogen synthesis
islets of langerhans cell Interactions
Insulin inhibits glucagon release (via somatostatin), thus preventing an opposing action on glucose levels.
Glucagon enhances insulin release, thus enabling the elevated glucose to be transported into cells.
what is diabetes mellitus
Results from a lack of secretion or effectiveness of insulin
what is type 1
insulin deficient, young
