LE 3.03 STOMACH, SPLEEN, AND PANCREAS.docx

I. Abdominal Viscera

  • The viscera of the abdomen constitute the majority of the alimentary system.

  • Key organs include the terminal esophagus, stomach, intestines, spleen, pancreas, liver, gallbladder, kidneys, and suprarenal glands.

  • Falciform ligament attaches to the anterior abdominal wall, dividing the liver into right and left lobes.

  • The greater omentum typically conceals most of the intestines.

II. Embryology

A. Stomach

  • Week 4: Gut tube dilates to form a spindle-shaped structure.

  • Week 5: Dorsal border grows faster forming greater curvature dorsally and lesser curvature ventrally.

  • Weeks 7-8: Stomach rotates 90 degrees clockwise along the longitudinal axis.

B. Omental Bursa

  • A peritoneal sac behind the stomach allowing its distension.

  • Formed by the stomach's rotation and incorporating dorsal mesogastrium.

C. Pancreas

  • Forms from dorsal and ventral pancreatic buds from the endoderm of the duodenum.

  • Buds fuse as the pancreas develops, with important structure typically forming a ring around the duodenum.

III. Stomach

A. Functions

  • Short-Term Storage Reservoir - Allows rapid consumption of large meals

  • Substantial Enzymatic Digestion - Chief function; especially for proteins.

  • Food Blender - Mixes food with gastric secretions producing chyme.

B. Parts

  • Cardia: Region around cardial orifice to the stomach.

  • Fundus: Vault above the cardial orifice, often contains gas.

  • Body: Major section of the stomach, located between fundus and pyloric antrum.

  • Pyloric Part: Funnel-shaped region including pyloric antrum and canal.

  • Curvatures:

    • Lesser: Shorter concave border, attached to lesser omentum.

    • Greater: Longer convex border, attached to the greater omentum.

C. Relations

  • Anterior: Diaphragm, liver, abdominal wall.

  • Posterior: Omental bursa, pancreas, retroperitoneal structures.

D. Arterial Supply

  • Supplied by branches of the celiac trunk: left gastric, splenic, and common hepatic arteries.

E. Celiac Trunk

  • Supplies lesser curvature, greater curvature, and upper body.

F. Venous Drainage

  • Drains primarily into the portal vein (various routes).

G. Lymphatic Drainage

  • Gastric lymphatics unite at pylorus; important groups identified for specific drainage.

H. Innervation

  • Sympathetic: Greater and lesser splanchnic nerves, coeliac plexus.

  • Parasympathetic: Vagus nerve from anterior and posterior gastric nerves.

IV. Pancreas

A. Function

  • Both exocrine (digestive enzymes) and endocrine (insulin and glucagon) functions.

B. Parts

  • Divided into head, neck, body, and tail.

  • The main pancreatic duct and accessory duct structure outlined.

C. Arterial Supply

  • Primarily from the splenic artery and pancreaticoduodenal arteries.

D. Venous Drainage

  • Excessively draining into the Portal, Splenic, and Superior mesenteric veins.

E. Lymphatic Drainage

  • Follows blood vessel drainage pattern, involving pancreaticosplenic nodes.

F. Innervation

  • Innervated by vagus and abdominopelvic splanchnic nerves through the celiac plexus.

V. Spleen

A. Function

  • Major functions in both immune response and recycling blood cells.

B. Surfaces

  • Diaphragmatic surface facing up and related to ribs.

C. Impressions

  • Various impressions by stomach, kidney, and colon indicated.

D. Accessory Spleen

  • Common occurrence (10%); often small and potentially left unremoved during splenectomy.

E. Arterial Supply

  • Largest branch of celiac trunk, splenic artery.

F. Venous and Lymphatic Drainage

  • The splenic vein joined by inferior mesenteric vein and drains to portal vein.

G. Innervation

  • Derived from the celiac plexus, primarily for vasomotor function.

References

  • Moore, K. (2014). Clinical Oriented Anatomy (7th ed.)

  • Lecturer’s Powerpoint

  • Lecture notes

  • Previous Transes