Anatomy

Question 1

Mobile part of the stomach?

Answer 1

Large midportion

Question 2

Blood supply of the stomach?

Answer 2

Celiac axis, which gives rise to:
Left and right gastric arteries (lesser curvature)
Right and left gastroepiploic arteries (greater curvature)

Question 3

Consistently largest artery to the stomach?

Answer 3

Left gastric artery
(Usually, arises directly from the celiac trunk, and divides into an ascending and descending branch along the lesser curvature).

Question 4

Second largest artery to the stomach?

Answer 4

Right gastroepiploic artery

Arises from gastroduodenal artery behind first part of duodenum

Question 5

The left gastroepiploic artery arises from?

Answer 5

From the splenic artery

Question 6

The right gastric artery arises from?

Answer 6

From the hepatic artery, near the pylorus and hepatoduodenal ligament.

Question 7

Venous drainage?

Answer 7

Gastric veins drain into portal vein
Right gastroepiploic vein drains into superior mesenteric
Left gastroepiploic vein drains into splenic

Question 8

Implications of good vasculature?

Answer 8

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.

Question 9

Lymphatic drainage?

Answer 9

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

Question 10

Innervation to the stomach?

Answer 10

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

Question 11

Anterior vagus branches

Answer 11

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”

Question 12

Posterior vagus branches

Answer 12

1) Branches to the celiac plexus
2) Continues along posterior lesser curvature
3) Posterior fundus branch, above esophageal hiatus (Criminal nerve of Grassi)

Question 13

Four layers of gastric wall?

Answer 13

1) Mucosa
2) Submucosa
3) Muscularis propria
4) Serosa

Question 14

Layers of the mucosa?

Answer 14

1) Epithelium (columnar glandular)
2) Lamina propria
3) Muscularis mucosa

Question 15

Role of epithelial cells in gastric mucosa?

Answer 15

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.

Question 16

Nature of glands in the cardia

Answer 16

Branched, secrete mucus and bicarbonate

Question 17

Nature of glands in the fundus and body

Answer 17

Tubular glands, deep pits
Contain:
- Parietal cells
- Chief cells
- Enterochromaffin-like cells
- G-cells
- D-cells

Question 18

Histology and role of parietal cells

Answer 18

• 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

Question 19

Histology and role of chief cells

Answer 19

• 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

Question 20

Nature of glands in the antrum

Answer 20

• Branched and shallow glands

- Contain gastric-secreting G cells and somatostatin-secreting D cells

Question 21

Histologic breakdown of normal stomach

Answer 21

44% chief (zymogenic) cells
40% mucous cells
13% oxyntic (parietal) cells
3% endocrine cells

Question 22

Composition of submucosa?

Answer 22

Branching blood vessels
Lymphatics
Collagen
Inflammatory cells
Nerve fibers
Ganglion cells of Meissner's autonomic submucosal plexus

The submucosa gives strength to GI anastomoses.

Question 23

Composition of gastric rugae?

Answer 23

Mucosa and submucosa

Question 24

Composition of Muscularis propria

Answer 24

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)

Question 25

Role of serosa

Answer 25

AKA visceral peritoneum

Provides tensile strength to gastric anastomoses