Stomach anatomy 10 marks shape ,parts, blood supply

Stomach anatomy 

  STOMACH 10 MARKS ANATOMY 

**Point Description **             

Shape Varies depending on distention and surrounding viscera.               

 - Empty: J-shaped.               

 - Distended: Pear-shaped (pyriform).               

 - Obese persons: Horizontal.               

**Features   **            

Two Orifices                

 - Cardiac orifice: Joins lower esophagus.               

 - Pyloric orifice: Opens into duodenum.               

Two Curvatures                

 - Lesser curvature: Attaches to lesser omentum.               

 - Greater curvature: Attaches to greater omentum and gastrosplenic ligament.               

**Two Parts  **              

 1. Cardiac part:               

 - Fundus: Upper convex dome above cardiac orifice.               

 - Body.               

 2. Pyloric part:               

 - Pyloric antrum.               

 - Pyloric canal.               

**Two Surfaces  **              

 - Anterosuperior surface.               

 - Posteroinferior surface.               

**Relations    **            

*Anteriorly Related to anterior abdominal wall, liver, and diaphragm. Feeding tube insertion site for complete esophageal obstruction.               

*Posteriorly Related to lesser sac, left kidney, left suprarenal gland, splenic artery, pancreas, splenic flexure of colon, transverse mesocolon, and spleen. Posterior perforation due to ulcers can damage these structures, especially the splenic artery, leading to peritoneal bleeding.               

*Blood Supply **Right and left gastric arteries (along lesser curvature), right and left gastroepiploic arteries (along greater curvature), a few short gastric arteries supplying stomach. Corresponding veins drain into superior mesenteric, splenic, and portal veins.               

**Lymphatic Drainage** Drains into pancreatico-splenic nodes (behind stomach along splenic artery), left gastric and right gastroepiploic nodes (near respective vessels), ultimately drains into coeliac group of lymph nodes.               

Structure Four layers:               

 - Mucosa (lined by simple columnar cells).               

 - Submucosa.               

 - Muscularis externa (smooth muscle fibers).               

 - Serosa.               

 Mucosal folds (rugae).               

 Gastric and pyloric glands.               

 Gastric glands contain:               

 - Chief/peptic cells (secrete pepsinogen and gastric lipase).               

 - Parietal/oxyntic cells (secrete HCl).               

 - Neck mucous cells (protect lining from acids and enzymes).               

 - Argentaffin cells (secrete gastrin and contain serotonin).               

**Nerve Supply **Sympathetic (T5-T9 spinal segments) and parasympathetic (vagus nerve).               

Parasympathetic Stimulates gastric musculature, inhibits pyloric sphincter.               

Sympathetic Motor to pyloric sphincter, inhibits gastric musculature.               

**Applied Aspects **             

1. Gastric disorders (dyspepsia) Anorexia, nausea, vomiting, epigastric discomfort or pain.               

2. Peptic ulcers Occur in stomach, lower esophagus, or duodenum (pepsin and HCl secretion sites).               

3. Gastric ulcers Common along lesser curvature, slow to heal and persist, treated with antacids to reduce HCl irritation or partial gastrectomy or vagotomy to promote healing.               

4. Gastric carcinoma Common along lesser curvature.              

HOW TO LABEL PARTS 

Shape: The stomach should be depicted slightly J-shaped when empty and pear-shaped when full.

Orifices:

Cardiac orifice: Label this at the upper left portion where the esophagus connects.

Pyloric orifice: Label this at the lower right portion where the stomach connects to the duodenum.

Curvatures:

Lesser curvature: Label this as the concave side along the top and right.

Greater curvature: Label this as the convex side along the bottom and left.

Parts:

Fundus: Label this as the dome-shaped upper portion.

Body: Label this as the main central portion.

Pyloric antrum: Label this as the wider lower portion.

Pyloric canal: Label this as the narrow, funnel-shaped terminal portion.

Surfaces:

Anterosuperior surface: Label this as the front upper surface.

Posteroinferior surface: Label this as the back lower surface.

Additional labels can include:

Rugae: Folds in the stomach lining.

Gastric glands: Glands in the stomach lining that produce digestive juices.