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Flashcards in Endocrine pancreas Deck (11)
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What are the two parts of a pancreas?

1. Exocrine

2. Endocrine


What are the characteristics of an exocrine pancreas?

Contains ducts and acinar tissue

Glands secrete proteolytic enzymes along the ducts

These include

Trypsin and Lipase


What are the characteristics of an endocrine pancreas?

Islets of Langerhaans - 1 million

Made of different cells

1. Beta cells - insulin

2. Alpha cells - glucagon

3. Delta cells - somatostatin

4. Epsilon cells - ghrelin


What are the two most important pancreatic hormones?

Glucagon and insulin


What are the features of insulin?

Acts on tyrosine kinase receptor

These work by phosphorylation of proteins following activation Cascade of phosphorylation -> signalling pathways

2 important signalling pathways are activated:

1. Anabolic pathways - lipogenesis, glycogenesis

2. Increases GLUT4 translocation in muscle and adipose tissue


What are the features of glucagon?

Acts through G-protein coupled receptors

Increases intracellular cAMP upon activation

Activates catabolic pathways -> glycogenolysis and gluconeogenesis


What hormone can inhibit insulin and glucagon?



How do B cells release insulin?

1. Glucose enters the b cells via GLUT2 transporters

2. The molecules are broken down into ATP

3. Increase in intracellular ATP causes the potassium ATPase to block

4. Potassium no longer leaves the cell

5. The build-up of intracellular potassium causes membrane depolarisation

6. Voltage-dependant calcium channels open

7. Calcium enters the cells and causes vesicles containing insulin to fuse with the cell membrane


Why is insulin difficult to isolate?

Exocrine enzymes would degrade the insulin if you tried to make pancreatic extract


When was insulin first isolated?

In 1921 by Banting and Best


What did Sanger do in 1952?

Discovered the amino acid sequence of insulin

This was the first peptide to be sequenced