Beetus 1 Flashcards
Pancreas is composed of two major types of tissues:
- Acini
- Islets of Langerhaans
What do Acini cells do?
- exocrine function
- secrete digestive juices into the duodenum
What do Islets of Langerhans do?
- endocrine
- secrete insulin and glucagon directly into the blood
What types of cells are contained in the islets?
- Alpha
- Beta
- Delta
- PP
These cells comprise about 60% of the islet cells
Beta cells
Where are beta cells located?
Mainly in the middle of each islet
Beta cells secrete
- amylin
- insulin
What does insulin do?
- facilitates entrance of glucose into cells
- lowers blood glucose
What does amylin do?
- inhibits insulin secretion
- any other effects unknown
These cells constitute about 25% of total islet cells
Alpha cells
What do alpha cells secrete?
Glucagon
What does glucagon do?
- Increases blood glucose by stimulating the liver and other storage cells
- done to release stored glucose
These cells constitute about 10% of the total islet cells
Delta cells
What do delta cells secrete?
Somatostatin
What does somatostatin do?
Helps regulate the release of insulin and glucagon
PP cells prevalence
Very few in number
What do PP cells do?
- secrete a hormone called pancreatic polypeptide
- uncertain function
The close interrelations among islet cell types allow:
- cell to cell communication
- direct control of secretion of some hormones by the others
How does insulin impact glucagon secretion?
Insulin inhibits glucagon
Amylin and insulin
Amylin inhibits insulin secretion
What does somatostatin inhibit?
Secretion of both insulin and glucagon
