Endocrine Pancreas Flashcards
What is the function of the pancreas?
1. Both an endocrine and exocrine gland A. Exocrine pancreas -99% of gland B. Endocrine pancreas -1% of gland
What is the primary role of the pancreatic hormones?
- Primary role is to maintain appropriate basal level of glucose in blood
A. 70-90 mg/dl - Balance accomplished by integration of glucose metabolic activity of liver, muscle and adipose tissue
What are the pancreatic hormones?
insulin and glucagon
What happens to glucose after a meal?
- muscle storage for later use: glycogen
- Energy for muscle and other tissue
- Storage as fat (triglycerides)
- Excretion in urine with high blood sugar
- Energy for CNS
- Liver storage for later use: glycogen
What is glycogenesis?
glucose -> glycogen
What is Glycogenolysis:
glycogen -> glucose
What is gluconeogenesis?
amino acids -> glucose
What is lipogenesis?
fatty acids & glycerol -> triglycerides
What is lipolysis?
triglycerides -> fatty acids & glycerol
What cells of the pancreas function as endocrine cells?
1. Pancreatic Islets A. Alpha – glucagon B. Beta – insulin C. Delta D. F cells
What is the function of the delta cells?
- Secrete somastatin
What is the function of the F cells?
Secrete pancreatic polypeptide
What is the function of somastatin?
A. Inhibits glucagon, insulin & panc polypeptide secretion
B. Slows the rate of nutrient entry into cells
What is the function of glucagon?
- Stimulates liver to break down glycogen
- Increase blood glucose
- Secreted during low blood glucose level
What is the function of insulin?
- Decrease blood glucose
- Secreted during high blood glucose level
- Stimulates uptake of glucose by cells
- Promotes muscle/adipose cells to take up glucose
- Synthesis of glycogen in muscle/liver
- Reduces lipolysis
What is the function of C peptide?
- Connection between the A and B chains of the insulin structure. provides an index of beta cell function for pts who are receiving exogenous insulin. Half life of insulin is 5 mins; most is destroyed by proteases after glucose is transported.
- provides an index of beta cell function for pts who are receiving exogenous insulin. Half life of insulin is 5 mins; x
- Measured by RIA
Where is the highest concentration of insulin receptors?
- Insulin receptors are present in almost all cell membranes
A. Highest concentration in liver, muscle, adipose tissue
What is the chain of events once insulin binds to the receptor proteins?
Stimulates a chain of events -> increase in number of glucose transport proteins in target cell membranes -> improved movement of glucose from plasma into cell cytosol
How does insulin affect the number of insulin receptors on cells?
Insulin increases the number of insulin? receptors
Where are GLUT-4 transporter proteins?
Muscle & fat cells contain a type of insulin-sensitive glucose transporter protein called GLUT-4
How does the binding of insulin affect the GLUT-4 transporters?
- Normally, a few GLUT-4 transporters are in the cell membrane
- Binding of insulin causes an recruitment of other GLUT-4 receptors from a cytoplasmic pool