Medicine Notes > Oxford Medicine Notes > Organisation of the Body Notes

Endocrine Pancreas Notes

This is a sample of our (approximately) 8 page long Endocrine Pancreas notes, which we sell as part of the Organisation of the Body Notes collection, a First package written at Oxford in 2014 that contains (approximately) 257 pages of notes across 38 different documents.

Learn more about our Organisation of the Body Notes

The original file is a 'Word (Docx)' whilst this sample is a 'PDF' representation of said file. This means that the formatting here may have errors. The original document you'll receive on purchase should have more polished formatting.

Endocrine Pancreas Revision

The following is a plain text extract of the PDF sample above, taken from our Organisation of the Body Notes. This text version has had its formatting removed so pay attention to its contents alone rather than its presentation. The version you download will have its original formatting intact and so will be much prettier to look at.

Endocrine pancreas Development
-pancreas develops from the endoderm of pancreatic buds- embryonic epithelium of pancreatic ducts contain both potential exocrine and endocrine cells. In development endocrine cells migrate from duct system and aggregated around capillaries to form Islets of langerhans- scattered throughout exocrine tissue has two types of glands: exocrine glands (secrete digestive enzymes into small intestine) and endocrine glands (islets of langerhans)
-islets contain 4 types of secretory cells (alpha, beta, sigma, F Light microscopy: each islet has 3000 secretory cells surrounded by fine collagenous network which has numerous fenestrated capillaries. A capsule surrounds each islet. Endocrine cells are small, pale stained, granular cytoplasm
-immunoperoxidase technique: identify different secretory cells based on their specific products
-B cells - 60% of cells in the islets, make up the central region, secrete insulin, proinsulin, C peptide
-alpha cells- 15% , found in the peripheral area, secrete glucagon
-sigma cells - 10% , scattered, secrete somatostain
-F cells -15% , found in the ventral region, secrete pancreatic polypeptide Innervation
-level of islet secretion occurs through innervations from both sympathetic and parasympathetic divisions of the ANS
-Parasympathetic innervations via the 'vagus nerve' increases insulin secretion
-sympathetic innervations-can be stimulatory/inhibitory depending on wheter B adrenergic (stimulatory) or a-adrenergic (inhibitory) Blood supply of the pancreas
-Rich blood supply- shown in specimens stained with red dye before fixationeach islet is supplied by three arterioles which ramify into a network of highly fenestrated capillaries
-Supply from branches of superior mesenteric and celiac arteries

-pancreatic veins drain into the hepatic portal vein- the liver is directly below the pancreas

Insulin Function: replenish fuel reserves in muscle, liver, adipose tissue
-during fasting B cells secrete less insulin- insulin decreases lipids are mobilised from adipose tissue, amino acids are mobilised from body proteins
-during feeding: insulin secretion increases-this decreases mobilisation of glycogen, triglycerides and stimulates uptake of carbohydrate, lipid and amino acid uptake by insulin sensitive target tissues
-insulin maintains the concentration of glucose in the plasma within narrow limits, allows the brain to have a constant supply of glucose very important for its function as it relies on glucose as its main energy supply Synthesis of insulin
-protein: made in the B cells of the islets of langerhans and expression of the gene forms preproinsulin
-the preproinsulin enters the rough endoplasmic reticulum where that starting sequence of 24 amino acids is cleaved to form proinsulin (has A,B,C domains)
-the trans-golgi packages the proinsulin and creates secretory granules. Proteases cleave the proinsulin at two spots and forms the C peptide, A and B chains
-the A and B chains are linked by two disulfide linkages and forms mature insulin. 21 amino acids on the A chain and 30 amino acids on the B chain.
-the secretory vesicle contains, proinsluin, insulin, C peptide - all three are released into the portal blood when glucose stimulates the B cell.
-C peptide has no biological action- but released in 1:1 ratio with insulinconcentration measured in urine determines the concentration of insulin in the blood
-proinsulin has some action, has 1/20th the potency as insulin
-60% secreted is insulin Control of insulin release a) increase in plasma glucose increases insulin secretion

****************************End Of Sample*****************************

Buy the full version of these notes or essay plans and more in our Organisation of the Body Notes.