1a Glucose Homeostasis Flashcards
What is significantly impaired when glucose concentration falls below normal levels?
Cerebral function
What bodily system is glucose particularly important for?
The functioning of the central nervous system
What is hypoglycemia?
Blood glucose concentration levels fall below a normal levels
What can happen is blood glucose Concentration falls below 2mmol/L
Unconsciousness, coma and ultimately death
What does persistent hyperglycemia result in?
Diabetes mellitus type II
What hormones act against hypoglycemia? - 4
Glucagon
Cortisol
Growth hormone
Catecholamines
What is the most prevalent form of diabetes?
Type 2 diabetes mellitus
What are the three types of diabetes
Type 1 DM
Type 2 DM
maturity onset diabetes of the young
state the cell types found in the pancreas - 2
Islets of Langerhans
Exocrine acinar cells
What is meant by the pancreas having retroperitoneal structure?
Has a peritoneum on the anterior side only
What are the small clumps of cells in the pancreas called?
Islets of Langerhans
What are exocrine acinar cells?
Cells that generate exocrine secretions
What are the three types of islet cells?
alpha, beta and delta cells
What are the alpha cells involved with?
Glucagon secretion
What are the beta cells in the islets of langerhans involved with?
Insulin secretion
What are the delta cells in the islet of langerhans involved with?
Somatostatin secretion
What do the gap junctions between the cells of the islets of Langerhans allow?
They allow small molecules to pass directly between cells - paracrine communication
What is the purpose of the tight junctions between the cells of the islets of langerhans?
Create small intercellular spaces
What effect does somatostatin have on the insulin and glucagon?
inhibitory
What type of communication is found between the islet cells?
Paracrine communication
What does insulin do?
Stimulates growth and development and reduces blood glucose
What increased effect does insulin secreted from the beta cells have on the liver? - 5
Increased:
- Glycolysis
- Glycogenesis
- Glucose transport into cells via GLUT 4
- amino acid transport
- lipogenesis
Where is GLUT 4 predominantly expressed?
Adipocytes and skeletal muscle
When blood glucose is high, what is released?
Insulin from the beta cells as well as some glucagon from the alpha cells to ensure that hypoglycaemia doesn’t occur
How does somatostatin affect the release of insulin from beta cells when there is a rise in blood glucose?
inhibits the release of insulin
How does glucagon affect the release of insulin from beta cells when there is a rise in blood glucose?
stimulates release of insulin
state the impact of insulin on:
amino acid transport
protein synthesis
lipogenesis?
Increases amino acid transport, protein synthesis and lipogenesis
What is released when blood glucose levels are lowered?
Alpha cells release glucagon
What affect does glucagon have? - 5
INCREASED:
- gluconeogenesis
- lipolysis
- blood glucose
- amino acid transport to the liver
- hepatic glycogenolysis
Is GLUT 2 insulin sensitive?
No