Pancreatic Function Lecture 19 Dr Mazen Alzaharna CC

Pancreatic Function Lecture 19 Dr. Mazen Alzaharna CC 2018/1

The Pancreas • Pancreas is a large gland • Involved in the digestive process but located outside the GI tract • Composed of both exocrine and endocrine functions • 15 -25 cm in length • 60 -100 gram in weight Dr. Mazen Alzaharna CC 2018/1 2

Types of Tissues • Two functionally different tissues: • Endocrine (hormone releasing) • The smaller component • consists of islet of langerhans – 4 cell types • Secrete 4 hormones • Insulin, glucagon, ghrelin & somatostatin • Exocrine (enzyme secreting) • • The larger component secrets 1. 5 – 2 L/day, rich in digestive enzymes has alkaline p. H due to its content of Na. HCO 3 Produced by pancreatic acinar cells Dr. Mazen Alzaharna CC 2018/1 3

Somatostatin Glucagon Insulin Dr. Mazen Alzaharna CC 2018/1 4

Functions • Completes the job of breaking down food using digestive enzymes of pancreas • Protein → trypsin, chymotrypsin • Carbohydrates → amylase • Fats → lipase, lecithinase • Secretes hormones that affect the level of sugar in the blood. • Insulin, glucagon • Produces chemicals that neutralize stomach acids that pass from the stomach into the small intestine • Na. HCO 3 • Most of the pancreatic action is under the hormonal control of secretin and Cholecystokinin Dr. Mazen Alzaharna CC 2018/1 5

Pancreatic disorders • The major disorders of the pancreas are: • Endocrine pancreas: • Diabetes Mellitus (DM) • Islet Cell Tumors • Exocrine pancreas: • Acute pancreatitis & chronic pancreatitis • Pancreatic cancer • Cystic fibrosis Dr. Mazen Alzaharna CC 2018/1 6

Islet Cell Tumors • Tumors of the pancreatic islets are rare in comparison with tumors of the exocrine pancreas. • Islet cell tumors of the pancreas affect endocrine capability • If tumor occurs in beta cells → hyperinsulinism → low blood sugar • Alpha cell tumors → ↑ glucagon → DM Dr. Mazen Alzaharna CC 2018/1 7

Pancreatitis • Inflammation of the pancreas • The exocrine pancreas produces a variety of enzymes, such as proteases, lipases, and saccharidases. • These enzymes start autodigestion of the pancreas which causes the pain and complications of pancreatitis. • About 80% of cases are associated with cholelithiasis and alcoholism. • Associated with raised levels of pancreatic enzymes (amylase and lipase) in blood and urine. Dr. Mazen Alzaharna CC 2018/1 8

Laboratory Findings • Marked elevation of the serum amylase during the first 24 hours, followed within 72 -96 hours by a rising serum lipase. • Hypocalcemia Dr. Mazen Alzaharna CC 2018/1 9

Pancreatic Cancer • Carcinoma of the pancreas refers to carcinoma of the exocrine pancreas • Almost always arising from ductal epithelial cells (adenocarcinoma). • Presentation often occurs as a result of metastases rather than as a direct effect of the primary tumor. Dr. Mazen Alzaharna CC 2018/1 10

Laboratory Finding • Tumor markers, include: • carcinoembryonic antigen (CEA), • CA 19 -9, • and CA 125, • All are associated with pancreatic cancer but are nonspecific and can be elevated in conditions other than malignancies Dr. Mazen Alzaharna CC 2018/1 11

Cystic Fibrosis • Cystic fibrosis is an inherited, autosomal recessive disease that affects nearly all exocrine glands in the body. • The disease is characterized by: • chronic obstructive pulmonary disease, • pancreatic insufficiency, • and abnormally high sweat electrolytes. • The disease causes the exocrine glands to become obstructed by viscous material. • The blockage leads to cellular damage within the tissue. • Pancreatic insufficiency leads to poor digestion and poor growth pattern with a deficiency of fat-soluble vitamins. Dr. Mazen Alzaharna CC 2018/1 12

Cystic Fibrosis • CF is caused by a mutation in the gene for the protein cystic fibrosis transmembrane conductance regulator (CFTR). • This gene is required to regulate the components of sweat, digestive juices, and mucus. • The diagnosis of cystic fibrosis is made by clinical symptoms and positive sweat chloride test. • People with cystic fibrosis have unusually large amounts of chloride in their sweat when compared to reference ranges of healthy individuals. • The sweat is collected on sterile gauze over a period of a few minutes and later analyzed for the amount of chloride present. • Genetic analysis can be used to counsel families for gene carrier status. Dr. Mazen Alzaharna CC 2018/1 13

Other Tests • Detection of malabsorption • Fecal fat test • Indicates either pancreatic dysfunction or intestinal malabsorption • D-xylose absorption test • A pentose sugar which does not require pancreatic enzymes for absorption • In normal individuals, a 25 g oral dose of D-xylose will be absorbed and excreted in the urine at approximately 4. 5 g in 5 hours. Dr. Mazen Alzaharna CC 2018/1 14

Other Tests • Measuring exocrine function • Secretin, chymotrypsin, cholecystokinin • Measuring endocrine function • insulin, glucose Dr. Mazen Alzaharna CC 2018/1 15

Case Study • A 38 -year-old man entered the emergency department with the complaint of severe, mid abdominal pain of 6 hours' duration. • The patient had a 15 -year history of alcoholism • He had last been hospitalized for acute alcoholism 3 months ago, at which time he had relatively minor abnormalities of liver function. • On this admission, his blood pressure was 80/40 mm Hg; Dr. Mazen Alzaharna CC 2018/1 16

Serum amylase 640 units (3. 5 -260 units) Calcium 4. 0 m. Eq/L (4. 5 -5. 5 m. Eq/L) Blood urea nitrogen 32 mg/d. L (8 -25 mg/d. L) White blood cell count 16, 500 Hemoglobin 12 g/d. L 1. What is the probable disease? • Acute pancreatitis Dr. Mazen Alzaharna CC 2018/1 17

2. What is the cause for the low serum calcium? • Enzymatic fat necrosis and digestion, which result in free fatty acids in abdominal adipose tissue. The fatty acids then bind calcium as they form fatty acid salts. 3. What is the cause for the increased blood urea nitrogen? • Shock, resulting in prerenal azotemia Dr. Mazen Alzaharna CC 2018/1 18