1 / 21

The Endocrine Pancreas

Explore the roles of different cell types, insulin, and glucagon balance in the endocrine pancreas. Learn about diabetes mellitus, the physiological actions of insulin and glucagon, and their regulation. Discover insights into insulin-dependent and non-insulin-dependent diabetes. Gain knowledge about glucose tolerance testing, ketone bodies, and acidosis. Delve into the functions and dysfunctions of the pancreas in maintaining glucose balance.

janat
Download Presentation

The Endocrine Pancreas

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Endocrine Pancreas Lecture Objectives: • what are the different cell types and what do they secrete? • what is the balance between insulin and glucagon? • what does insulin do? • what is Diabetes Mellitus?

  2. The Pancreas • 98% of pancreas is dedicated to exocrine secretion • 2% of pancreas is dedicated to endocrine secretion • islets of Langerhans • receive both sympathetic and parasympathetic innervation

  3. Islets of Langerhans • islets are spread throughout the pancreas • 4 cell types • alpha cells secrete glucagon (20%) • beta cells secrete insulin (75%) • delta cells secrete somatostatin (<5%) • F or PP cells secrete pancreatic polypeptide (rare)

  4. Balance Between Insulin and Glucagon

  5. Insulin • synthesized as proinsulin and converted to a polypeptide • sequence conserved between species - development of antibodies

  6. Physiological Actions of Insulin • increases uptake and storage of glucose • stimulates glycogenesis • inhibits lypolysis, promotes fat uptake and storage • increases protein synthesis

  7. Regulation of Insulin Secretion • primary determinant = plasma glucose level • increased plasma amino acids • release of gastrointestinal hormones (GIP) • parasympathetic stimulation - triphasic response

  8. Glucagon • small protein released from alpha cells • prevents hypoglycemia following high protein meal • helps mobilize glucose during exercise

  9. Physiological Actions of Glucagon • glycogenolysis • glyconeogenesis • lipolytic • ketogenic gluconeogenesis

  10. Regulation of Glucagon Secretion • increased by decreased plasma glucose • increased by elevated plasma amino acids • increased by exercise • pancreatic sympathetic stimulation

  11. Diabetes Mellitus • most common endocrine disorder • characterized by polyuria, polydipsia, weight loss despite polyphagia, hyperglycemia, glucosuria, ketosis, acidosis • primary cause = reduced entry of glucose into peripheral tissues

  12. Insulin Dependent Diabetes Mellitus (IDDM) • also called type I or juvenile onset • associated with ketosis and acidosis • pathological changes in beta cells • plasma insulin low or undetectable • treatment = insulin injection

  13. Insulin Shock • insulin excess causes hypoglycemia • lack of fuel (glucose) for brain results in coma • hypoglycemia normally triggers secretion of: • glucagon • epinephrine • cortisol • growth hormone

  14. Non-Insulin Dependent Diabetes Mellitus (NIDDM) • also called type II or adult onset • patients are generally obese • insulin levels can be normal • insulin receptors downregulated • treatment = diet, sulfonylureas

  15. Glucose Tolerance Test • administer a glucose challenge and monitor blood glucose levels • blood glucose rises higher and returns to baseline more slowly in diabetics

  16. Ketone Bodies and Acidosis acetyl-CoA acetoacetate acetone B-hydroxybutyrate • decreased pH • respiration changes • acidic urine • can lead to coma

More Related