The Pancreas - PDF

							PANCREAS
Histological four types of cells Alpha cells – secrete glucagon Beta cells --- insulin D cells F cells -somatostatin pancreatic polypeptide

INSULIN
ACTIONS 1. CARBOHYDRATE METABOLISM ANTIGLUCONEOGENIC  Increases entry of glucose into skeletal muscle, cardiac muscle smooth muscles
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Increases peripheral utilization of glucose Increases glycolysis in liver, muscles, adipose tissue Increases synthesis of glycogen

2. FAT METABOLISM ANTILIPOLYTIC ACTION  Increases synthesis of FFA by stimulating lipoprotein lipase  Inhibits hormone sensitive lipase
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3. PROTEIN METABOLISM ANABOLIC ACTION  Decreases protein breakdown  Increases protein synthesis in muscles

MECHANSIM FACILITATED Diffusion by glucose transporters Decrease cAMP formation by inhibiting the activity of adenylyl cyclase activity.

DIABETES MELLITUS INSULIN deficiency leads to diabetes mellitus DM I DM II

Predisposing factors  Genetic  Age more common with increasing age  Obesity

CLINICAL FEATURES
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Insulin deficiency leads to hyperglycemia due to decreased peripheral utilization of glucose by cells Glycosuria Polyuria Polydipsia Dehydration Loss of weight Loss of resistance to infections

PATHOPHYSISOLOGY INSULIN DEFICIENCY Protein metabolism metabolism ↓ Increased catabolism effect ↓ Increased amino acids ↓ NITORGEN LOSS IN URINE ↓ ketogenesis DEHYDRATION KETOACIDOSIS ↓ ↓ ↓ ↓ ↓ DEHYDRATION ↓ Circulatory collapse ↓ Hypotension, Renal failure ↓ COMA ↓ DEATH ↓ ↓ metabolic acidosis carbohydrate metabolism ↓ hyperglycemia ↓ glycosuria ↓ polyuria, polydipsia ↓ ↓ fat ↓ lipolytic ↓ Increased FFA ↓ increased ↓ ↓

Electrotype and water IMBALANCE

COMPLICATIONS ATHEROSLCEROSIS Nephropathy Retinopathy Neuropathy HYPOGLYCEMIA INSULIN EXCESS

Blood glucose < 60 mg% Clinical features  Confusion  Irritability, convulsions, fatigue  Stimulation of sympathetic activity leading to palpitation, tremors, tachycardia, anxiety, nervousness Hypoglycemia is compensated by
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Increased glucagon secretion Increased sympathetic stimulation Increased glucocorticoids

REGULATORY MECHANISMS Factors STIMULATING INSULIN CARBOHYDRATE PROTEIN FAT NEURAL HORMONAL ↓ ↓ ↓ ↓ Hyperglycemia increased amino acids ketoacids parasympathetic stimulation ↓ ↓ Increased blood glucose Vagal GH GLUCAGON GASTRIN SECRETIN

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GLUCAGON
Secreted by alpha cells of pancreas Causes increased level of blood glucose in case of hypoglycemia ACTIONS GLUCONEOGENIC GLYCOGENOLYTIC, LIPOLYTIC, KETOGENIC HORMONE
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Stimulates gluconeogenesis Stimulates glycogenolysis Stimulates breakdown of glycogen into glucose LIPOLYTIC ACTION increase FFA into blood

Factors stimulating glucagon I. Hypoglycemia II. Increased amino acids in blood III. Symapathetic stimulation IV. GIT hormones -- Gastrin Secretin Factors decreasing glucagon stimulation I. Hyperglycemia II. FFA III. Insulin

MULTIPLE CHOICE QUESTIONS: PANCREAS 1. Insulin is secreted by a) Alpha cells. b) Beta cells. c) D cells. d) F cells. 2. One of the following statements is false regarding insulin a) Increases peripheral utilization of glucose. b) Increases synthesis of glycogen. c) Increases glycer rrrrrrrrrrr in liver. d) Increases gluconeogenesis.

3. One of the following is false a) Insulin causes potassium to enter the cells. b) Insulin deficiency leads to diabetes inspidus. c) Insulin decrease protein breaks down. d) Insulin inhibits hormone sensitive lipase. 4.Clinical features in patient with diabetes mellitus are a) b) c) d) Polydipsia. Polyphagia. Polyuria. Loss of weight.

5. Insulin deficiency leads to all except a) Increase protein breakdown. b) Hyperglycemia. c) Increased resistance to infections. d) Increase ketogenesis.

6. Hypoglycemia leads to all except

a) Confusion b) Convulsions. c) Bradycardia, d) Diarrhea 7. Hypoglycemia is compensated by all except a) Increased glucagon secretion. b) Increased glucocorticoids. c) Increased parasympathetic stimulation. d) Increased sympathetic stimulation. 8. One of the following is not action of glucagon a) Gluconeogenesis. b) Glycogenolysis. c) Lipolytic. d) Glycolysis. 9. Factors stimulating glucagon except a) Hypoglcemia b) Sympathetic stimulation. c) Gastrin d) FFA