Describes in detail the endocrine function of the pancreas. Also discusses type 1 and type 2 diabetes, diabetic ketoacidosis and hyperglycaemic hyperosmolar state (HHS). Discusses macrovascular and microvascular complications of diabetes. Finally the medications, their mechanism of actions and comm...
Divided into Pancreatic islets (Islets of Langerhans), with
millions of islets found in the pancreas. This comprises
the endocrine portion of the pancreas
Beta cells —→ Insulin (found centrally in islets and
most abundant)
Alpha cells —→ Glucagon (found outer islets)
Delta cells —→ Somatostatin (found outer islets)
Insulin
Protein hormone synthesised by Beta cells
Synthesised as preproinsulin in rough ER, then
cleaved to proinsulin and transported to Golgi
apparatus and finally turned to insulin and c-peptide in
secretory granules
Pancreas - Endocrine 1
, C-peptide can be used as an indicator of insulin
production, as it has a higher half life than insulin
Insulin release:
Promotes glucose uptake in adipose (fat) and skeletal muscle
Promotes glycogen synthesis through glycogen synthase
Inhibits gluconeogenesis
Increased fatty acid synthesis
Stimulates protein synthesis.
Through stimulating entry of amino acids into cells
^ above important as side effect of insulin therapy is weight gain.
Lowers potassium, which is why insulin + glucose used to treat hyperkalemia
Enhanced the activity of Na-K-ATPase pump in skeletal muscle
Insulin effects:
Insulin release is glucose dependent, the
more glucose that enters beta cell, the
more insulin released.
Glucose enters beta cells via GLUT-2
ATP produced through Glucokinase and
other enzymes
ATP production closes potassium channels
Depolarisation of Beta cell as potassium
stuck in cell
voltage gated calcium channels to open
resulting influx of calcium within the cell,
causes exocytosis of stored insulin.
Pancreas - Endocrine 2
, Amino acids can trigger the release of insulin too.
Production of insulin inhibited by epinephrine (adrenaline), as it acts strongly on the
alpha-2 receptors, resulting in greater plasma glucose (fight or flight response)
Glucagon
Protein hormone which is synthesised by Alpha cells
Opposes the action of Insulin, and thus is released during low plasma glucose
levels.
Increases amino acid uptake in liver, so serum amino acid levels will fall.
Glucagon receptors found mostly in liver, most other tissue have lower densities of
glucagon receptors.
Glucagon receptors NOT found in skeletal muscles.
Important enzymes and transports
Glucokinase
Glucokinase is a Beta cell enzyme found in liver and pancreas, involved in first step
of glycolysis
Insulin activates glucokinase, and promotes transcription.
Works better with high glucose concentration (inactive when glucose levels low),
and can convert lots of glucose.
GLUT-2:
Pancreas - Endocrine 3
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller kathandesai. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £7.49. You're not tied to anything after your purchase.
