Pancreas gland and its Hormones insulin and glucagon.pptx

Pancreas and its hormones descriptive notes along with pictures

1. Pancreas and its Hormones By D. Joy Merlin

2. Pancreas It is a dual function organ situated in the loop of stomach and duodenum. Its exocrine part –digestive enzymes Endocrine part – hormones- insulin,glucagon . It is made up of islet of langerhans cells. Exocrine cells called acini , which are involved in the synthesis of pancreatic juice. It will be helpful in digestion of protein, fat and carbohydrates in food.

3. Islets of langerhans Islets of langerhans , which contains 3 types of cells: The alpha, α The beta, β The gamma, γ The delta, δ

4. In human pancreas, about 2millions islets are there. 65% - beta cells – responsible for the synthesis of insulin. 25 % - alpha cells- responsible for the synthesis of glucagon . 5 to 10% - delta – secrete somatostatin . In addition, other type of cells- PP cells- secrete Pancreatic Peptide . The hormones secreted in islets directly oured into the blood stream.

5. Insulin Insulin is a small protein hormone secreted by beta cells of islets of langerhans . In 1922, Banting and Best, isolated insulin from pancreas for the first time. It composed of 2 polypetides , A and B chains which are held together with di-sulhide bonds. The chain A composed of 30 aa’s The chain B composed of 21 aa’s

6. Thus, insulin has 51 aa’s with M.wt : 6000 daltons . Biosynthesis of Insulin Synthesized by direct transcription and translation process of gene. Precursor of insulin is Proinsulin , synthesized in microsomal fraction of ancreatic beta cells as a long chain with M.wt : 9000 da . Post-translational modification gives 31aa C- petide by proteolytic enzyme treatment.

7. Insulin ( proinsulin ) stored in granules of Golgi body, which is resent in Beta cells. It will be released when it is needed.

8. Pathophysiology Diabetes Mellitus This condition caused by deficiency in the secretion or action of insulin. "Diabetes Mellitus" means "excessive excretion of sweet urine" Nearly 10% of Indian population shows some degree of abnormality in glucose metabolism.

9. Two major classes of DM: Type l diabetes Mellitus, or insulin-dependent diabetes Mellitus ( IDDM ). Type ll diabetes Mellitus, or non-insulin-dependent diabetes Mellitus ( NIDDM ), also called as resistant diabetes . In Type 1 diabetis the disease begins early in life and quickly becomes severe. It is due to inability to produce sufficient insulin. IDDM requires insulin therapy and careful lifelong control of the balance between dietary intake and insulin dose

10. Characteristic symptom of Type 1 (and type 2) diabetes are excessive thirst and frequent urination (polyuria) leading to intake of large volumes of water (polydipsia). These symptoms are due to the excretion of large amounts of glucose in the urine, a condition known as glycosuria. Type 2 diabetes is slow to develop (typically in older, obese individuals ) and the symptoms are milder and often go unrecognised at first.

11. Hypoglycemia It is defined as syndrome characterized by Low plasma glucose and associated group of symptoms. In infant the hypoglycemia that is its plasma glucose concentration is less than 25 mg per 100ml of blood. In adults two groups of symptoms occur depending upon whether the hypoglycemia is acute or chronic.

12. If the Low plasma glucose occurs rapidly symptoms of sweating, shakiness ,trembling, weakness and anxiety are produced. If the reduction in plasma glucose occurs slowly, headache, irritability, lethargy and other central nervous system symptoms predominate. Prolonged ingestion of ethanol and certain Other Drugs which can damage the liver cells and hamper the supply of liver glycogen for glycogenolysis main cause for fasting hypoglycemia.