Anatomy Flashcards
Mobile part of the stomach?
Large midportion
Blood supply of the stomach?
Celiac axis, which gives rise to:
Left and right gastric arteries (lesser curvature)
Right and left gastroepiploic arteries (greater curvature)
Consistently largest artery to the stomach?
Left gastric artery
(Usually, arises directly from the celiac trunk, and divides into an ascending and descending branch along the lesser curvature).
Second largest artery to the stomach?
Right gastroepiploic artery
Arises from gastroduodenal artery behind first part of duodenum
The left gastroepiploic artery arises from?
From the splenic artery
The right gastric artery arises from?
From the hepatic artery, near the pylorus and hepatoduodenal ligament.
Venous drainage?
Gastric veins drain into portal vein
Right gastroepiploic vein drains into superior mesenteric
Left gastroepiploic vein drains into splenic
Implications of good vasculature?
1) At least 2 out of 4 arteries can be ligated with impunity.
2) Gastric remnant is adequately supplied by short gastric arteries (if splenic artery intact)
3) Gastric bleeding requires embolization of more than 1 feeding artery
4) A distal splenorenal shunt (connects distal splenic vein to side of left renal vein) can decompress esophagogastric varices in portal hypertension.
Lymphatic drainage?
Cardia and medial corpus: Left gastric and celiac axis nodes
Lesser curvature antrum: Right gastric and pyloric nodes
Greater curvature antrum: Right gastroepiploic chain
Greater curvature proximal: Left gastroepiploic/splenic hilum
Greater and lesser curvature: Celiac nodal basin
Innervation to the stomach?
1) Extrinsic parasympathetic: Vagus nerves
Vargas nucleus in floor of fourth cerebral ventricle –>
Carotid sheath –>
Mediastinum –>
Branches out into recurrent laryngeal nerve and esophageal branches, which come together above esophageal hiatus to form the left (anterior) and right (posterior) vagal trunks
2) Extrinsic sympathetic: From T5-T10
Splanchnic nerves to the celiac ganglion
Celiac ganglion to stomach
3) Intrinsic
Neurons in myenteric and submucosal
Anterior vagus branches
1) Branches to the liver (in gastrohepatic ligament)
2) Anterior nerve of Latarjet
- Segmental branches to body of stomach
- Terminates near the angular is incisura as the “crow’s foot”
Posterior vagus branches
1) Branches to the celiac plexus
2) Continues along posterior lesser curvature
3) Posterior fundus branch, above esophageal hiatus (Criminal nerve of Grassi)
Four layers of gastric wall?
1) Mucosa
2) Submucosa
3) Muscularis propria
4) Serosa
Layers of the mucosa?
1) Epithelium (columnar glandular)
2) Lamina propria
3) Muscularis mucosa
Role of epithelial cells in gastric mucosa?
All epithelial cells of the stomach (except endocrine cells) contain carbonic anhydrase, and produce bicarbonate.
These play an important role in protecting the stomach from acid, injury and gastric irritants.
Nature of glands in the cardia
Branched, secrete mucus and bicarbonate
Nature of glands in the fundus and body
Tubular glands, deep pits Contain: - Parietal cells - Chief cells - Enterochromaffin-like cells - G-cells - D-cells
Histology and role of parietal cells
- Ultrastructural appearance with secretory canaliculi
- Cytoplasmic tubulovesicles, containing acid-producing H/K-ATPase (proton pump)
- Most mitochondria-rich cell
- Secrete acid and intrinsic factor in the gastric lumen
- Secrete bicarbonate into the intercellular space
Histology and role of chief cells
- AKA Zymogenic cells
- Protein-synthesizing cells: basal granular endoplasmic reticulum, supranuclear Golgi apparatus, apical Zymogen granules
- Secrete proenzyme forms of pepsinogen (I > II) –> activated in acidic luminal environment
Nature of glands in the antrum
- Branched and shallow glands
- Contain gastric-secreting G cells and somatostatin-secreting D cells
Histologic breakdown of normal stomach
44% chief (zymogenic) cells
40% mucous cells
13% oxyntic (parietal) cells
3% endocrine cells
Composition of submucosa?
Branching blood vessels Lymphatics Collagen Inflammatory cells Nerve fibers Ganglion cells of Meissner's autonomic submucosal plexus
The submucosa gives strength to GI anastomoses.
Composition of gastric rugae?
Mucosa and submucosa
Composition of Muscularis propria
AKA Muscularis externa
1) Incomplete inner oblique layer
2) Complete middle circular layer (continues from esophageal and pyloric circular muscles)
3) Complete outer longitudinal layer (continues from esophageal and duodenal longitudinal layer)
4) Auerbach’s myenteric plexus
5) Interstitial cells of Cajal (pacemaker cells)
