Question

Describe the anatomy and physiology of the Pancreas. Focus on the exocrine digestive functions.

Answer 1

ANSWERS

ANATOMY OF PANCREAS

Shape : prismoid in shape and appears triangular in cut section

Location: behind the stomach ,in left upper quadrant and surrounded by the spleen, liver and small intestine. The pancreas lies transversely between the duodenum on the right and the spleen on the left.

Measurement : 6 inches (15.24 centimeters) long, oblong and flat.

Borders : superior, inferior, and anterior borders

Surfaces :anterosuperior, anteroinferior, and posterior surfaces.

Divisions : pancreas is divided into a head, neck, body, and tail.

• The head lies on the inferior vena cava and renal vein and is surrounded by the C loop of the duodenum.
• The neck of the pancreas is between head and body .The neck is about 2 cm (0.79cm) in width. The neck lies mostly behind the pylorus of the stomach, and is covered with peritoneum.
• The body is the middle part of the pancreas between the neck and the tail.
• The tail of the pancreas extends up to splenic hilum

Blood supply : Pancreatic branches of the splenic artery supplies pa ncreas. The head is additionally supplied by the superior and inferior pancreaticoduodenal arteries which are branches of the gastroduodenala superior mesenteric arteries respectively. Venous supply ; pancreaticoduodenal vein and pancreatic veins

Lymphatic supply : Splenic lymph nodes, celiac lymph nodes and superior mesenteric lymph nodes.

Nerve supply : Pancreatic plexus, celiac ganglia, vagus nerve.

PHYSIOLOGY OF PANCREAS

The pancreas has both an endocrine and a digestive exocrine function.

• As endocrine gland, it regulate blood sugar levels, secreting the hormones insulin, glucagon, somatostatin, and pancreatic polypeptide.
• As a part of the digestive system, it functions as an exocrine gland secreting pancreatic juice into the duodenum through the pancreatic duct.

Exocrine Function:
The pancreas contains exocrine glands that produce enzymes necessary for digestion. These are secreted into the middle of the acinus ,accumulate in intralobular ducts, which drain to the main pancreatic duct, which drains directly into the duodenum. About 1.5 - 3 liters of fluid are secreted in this manner every day. These enzymes are rich in bicarbonate. Bicarbonate helps maintain an alkaline pH for the fluid, helps to neutralise the stomach acids that enter the duodenum.

• Trypsin and chymotrypsin to digest proteins.
• Amylase for the digestion of carbohydrates
• Lipase to break down fats.

Protein digestion begins with activation of trypsinogen to trypsin. The free trypsin then cleaves the rest of the trypsinogen, as well as chymotrypsinogen to its active form chymotrypsin.Enzymes secreted involved in the digestion of fats include lipase, phospholipase A2, lysophospholipase, and cholesterol esterase.Enzymes that breakdown starch and other carbohydrates include amylase.