Stomach pptx - د. منال (الفصل الثاني)

• StomachManal alahmad

Stomach

Is the most expanded part of the digestive tract, it is sac like structure.

Functions of stomach:

1-Mechanical: store,mix and digest the food
2-Chemical: secretion of enzymes and acids
3-absorptive function: absorbs water, alcohol and certain drugs

Stomach

The Stomach is divided into 4 regions:

Cardiac

fundus
body
Pylorus

Stomach

• The wall of stomach consists of 4 layers:
• Mucosa
• Submucosa
• Muscularis Externa
• Serosa

Stomach

• Mucosa
• Consists of:
• 1- Epithelium : simple columnar epithelium
• 2-Lamina propria: Ioose connective tissue
• 3-muscularis mucosae: smooth muscle (inner circular and outer longitudinal layers).
• Rugae: are longitudinal folds in the mucous layer that appear when the stomach is empty and these folds disappear when the stomach is filled
• Gastraic pits: are considered as ducts for gastric glands which occur in lamina propria

Cardio esophageal

junction

stratified sq. epith
columnar epthelium
Cardiac gland

Stomach

• Submucosa
• the dense irregular collagenous connective tissue
this layer contains blood vessels

Stomach

• Muscularis Externa.
• consists of 3 substantial layers of smooth muscle.
Inner oblique layer :
b. Middle circular layer :(is clearly evident along the entire stomach and especially pronounced pyloric region where it forms the pyloric sphincter)

Outer longitudinal layer:

• ****** Aurbach’s plexus is found between the circular and longitudinal layers

Stomach

• Serosa :
loose areolar connective tissue covered by a mesothelium.

Stomach
Gastric glands: it consists of isthmus , neck and base , it divided into
1-Gardiac glands:
2-Pyloric glands : *-long gastric pits and short glands
*- simple and tend to branch
3-Fundic glands: *-short gastric pits and long glands
*-simple ,tubular and branched
this gland is lined by 5 types of cells Mucus neck cells, Regenerative (Stem) cells, Parietal cells, Chief (Peptic) cells, Enteroendocrine cells .