MEH - Endocrine Pancreas Flashcards Preview

CJ: UoL Medicine Semester Two (ESA2) > MEH - Endocrine Pancreas > Flashcards

Flashcards in MEH - Endocrine Pancreas Deck (15)
Loading flashcards...

How does the pancreas develop embryologically?

An out-growth of the foregut


What are the two functions of the pancreas?

- produces digestive enzymes secreted directly into the duodenum (exocrine action)
- produces hormones from Islets of Langerhans (endocrine)


Give some examples of hormones secreted by the pancreas

- insulin
- glucagon
- somatostatin
- pancreatic polypeptide
- ghrelin
- gastrin
- vasoactive intestinal peptide


Which two hormones control plasma glucose?

Insulin and glucagon


Why is it important that plasma glucose is kept stable?

The brain uses glucose at the fastest rate in the body and relies on the blood glucose


What transport proteins are used for insulin and glucagon?

Trick question - none, as they are carried dissolved in the plasma


How long is the half-life of insulin and glucagon?

Around five minutes - must be short due to constant changes in serum glucose levels


What is the structure of insulin?

It is an alpha-helix structured peptide, which consists of two unbranched peptide chains connected by 2 disulphide bridges to ensure stability


What is margination?

Movement of insulin storage vesicles to the cell surface and exocytosis


How do K ATP channels regulate insulin release from beta cells?

If glucose is present, it enters the cell and is metabolised. This increases cell [ATP], so the K ATP channels stay shut. The membrane depolarises and Ca2+ channels open, driving insulin release.

If no glucose was present, the K ATP channels would open and hyperpolarise the membrane, so no insulin would be released.


What is the structure of an insulin receptor?

Two identical subunits spanning the cell membrane - one alpha bit and one beta bit joined together by a disulphide bond (so four pieces in total: alpha+beta x 2)


What are the effects of insulin?

- increases glycogen synthesis
- increases uptake of amino acids in muscles
- inhibits breakdown of amino acids in liver
- increases storage of triglycerides in adipose tissue


What is glucagon secreted by?

Alpha cells due to low glucose levels


What is the structure of glucagon?

29 amino acids in one polypeptide chain - no disulphides bridges means it has a flexible structure


What are the effects of glucagon?

Increases rate of glycogen breakdown in the liver and stimulates gluconeogenesis

Decks in CJ: UoL Medicine Semester Two (ESA2) Class (87):