Stomach and Duodenum L 1 Hawler Medical University

Stomach and Duodenum L 1 Hawler Medical University College of Medicine Department: Surgery Rawand M. Haweizy Senior Lecturer M. B. Ch. B, MSc, MRCS e. mail: rawand_haweizy@yahoo. com

Objectives To recognize and understand: • The anatomy of the stomach and duodenum and its relations to surrounding structures. • Simple structures of stomach and duodenum to understand disease process that affect these two organs.

Contents l l l Introduction Embryology Anatomy and structures of stomach & duodenum

Introduction l The function of the stomach is to act as a reservoir for ingested food. l It also serves to break down foodstuffs mechanically and commence the processes of digestion before these products are passed into the duodenum.

Embryology l Stomach and duodenum develop from the caudal portion of the embryonic foregut. l Development starts in the 5 th week of gestation. l Rate of growth of the left gastric wall >right gastric wall.

Anatomy l l l A pliable, saccular organ. Located in the LUQ and epigastrium. Separated from the GI tract (2 locations).

Gross Anatomy l l Proximal= Cardia (attaches to esophagus) attaches at the LES. Fundus= most superior portion, receives food. Body= largest portion, contains parietal, chief and ECL cells. Distal= antrum, contains the G cells.

Anatomic relationships l Anteriorly: left hemidiaphragm, left lobe of the liver, anterior portion of the right lobe of the liver, parietal surface of the abdominal wall. l Posteriorly: left diaphragm, left adrenal, neck, tail, body of the pancreas, aorta and celiac trunk. l Inferiorly: transverse colon and its mesentery.

Anatomic relationships cont, d l l Stomach almost entirely covered with peritoneum. Peritoneum forms outer gastric serosa. Beneath serosa the muscularis propria. The MP is made up of 3 layers of smooth muscle. Ø Outer longitudinal Ø Middle circular Ø Inner most oblique

Anatomy&structure

Anatomy&structure cont, d l l l Within layers of MP, (myenteric plexus = Auerbach). Submucosa between MP and mucosa( strongest layer). Submucosa ( lypmhatics & Meissner’s plexus).

Anatomy&structure cont, d l Mucosa: 1. 2. 3. Surface epithelium (columnar). Lamina propria l Connective tissue layer supports surface epithelium. Muscularis mucosae ( rugal folds). l MM : boundary for invasive/non invasive gastric cancer.

Cell Types l Parietal: – – l Mucus: – – l Location: Body Function: secrete acid and intrinsic factor Location: Body, Antrum Function: mucus production Chief: – – Location: Body Function: produce Pepsin

Cell Types cont, d l Surface epithelium: – – l ECL: – – l Location: Diffuse Function: produce mucus, bicarb, prostaglandins(? ) Location: Body Function: Histamine production G cells: – – Location: Antrum Function: Gastrin production

Cell Types cont, d l D cells: – – Location: Body, Antrum Function: produce Somatostatin

Blood Supply l l l l R&L gastrics R&L gastroepiploics Short gastrics Inferior phrenics Gastroduodenal Venous drainage: R&L gastric veins

Blood supply cont, d

Nerve supply l Vagal trunks: – Left – anterior – Hepatic branch – Anterior gastric wall – Right – posterior – Celiac division – Posterior gastric wall

Nerve supply cont, d

Lymphatic drainage l l l l Gastric nodes Hepatic nodes Coeliac nodes Suprapyloric nodes Subpyloric nodes Gastroepiploic nodes Splenic hilar nodes

Lymphatic drainage cont, d

Duodenum First part of small intestine. l Receives partially digested food from stomach l Duodenum 25 cm (10 inches) l Roughly horseshoe-shaped l Divided into four segments: 1. Superior, 2. Descending, 3. Horizontal, and 4. Ascending duodenum l

Duodenum cont, d

Duodenum cont, d l l l Duodenum lined ( mucus-secreting columnar epithelium). Brunner’s glands lie beneath the mucosa Endocrine cells in the duodenum produce (cholecystokinin and secretin)

Duodenum cont, d Blood supply l l Superior pancreaticodoudenal artery. Inferior pancreaticodoudenal artery. Nerves Ø Parasympathetic and sympathetic nerves. Lymphatic drainage Ø Lymphatics from duodenum( pancreaticoduodenal, supra- and infrapyloric, superior mesenteric, and celiac lymph nodes)

Duodenum cont, d

Summary Ø Ø Ø The stomach acts as a reservoir food and commences the process of digestion. Knowledge of structures and anatomy of stomach and duodenum gives students orientations about many pathological processes that affect these two organs. Next lecture: physiology and functions of stomach and duodenum, investigations, H. Pylori.