digestive system stomach

V-Stomach :
Is an expanded part of the digestive tube that lie under the diaphragum , is divided into :
Cardiac is the superior region , fundic is the body form , and the pyloric, which is the inferior region of the stomach . The stomach wall exhibit four general layers :
• Mucosa
The gastric mucosa consists of a surface epithelium that invaginates to varying extents in to the lamina propria, forming gastric pits . Emptying in to gastric pits are branched, tubular glands ( cardiac, gastric , and pyloric ) characteristic of each region of the stomach .
The lamina propria of the stomach is composed of loose connective tissue interspersed with smooth muscle and lymphoid cells. Separating the mucosa from the underlying submucosa is a layer of smooth muscle ,the muscularis mucosa , this layer is composed of an outer group of longitudinal fibers and circular fibers closer to the lumen .
• Submucosa
Consists of connective tissue with numerous lymph vessels, capillaries, and another contents.
• Muscularis externa
Consists of three layers of smooth muscle in different arrangements(directions) ,the internal is oblique ,the middle is circular, and the external is longitudinal layer.
• Serosa
Is thin and covered by mesothelium.








VI-Small intestine

Is relatively long permitting prolonged contact between food and digestive enzymes .It consists of 3 segments : duodenum, jejunum, and ileum.

• Mucosa :- The small intestine presents folds like finger, known as villi , that change their morphology and decrease in height from the duodenum to the ileum . Villi are elevations of epithelially covered lamina propria .
1-Epithelium, the simple columnar epithelium consists of goblet cells
2-Lamina propria, composed of loose connective tissue ,houses glands, known as the crypts of Lieberkuhn ,that extend to the muscularis mucosae
3-muscularis mucosae , consists of an inner circular and an outer longitudinal layer of smooth muscle .
• Submucosa :- display spiral fold , plicae circulars .
• Muscularis externa , is composed of the usual inner circular and outer longitudinal layers of smooth muscle, with Auerbach, s plexus.
• Serosa :- composed of connective tissue covered with mesothelium.



1- Duodenum:
Has the same layers above ,but it has a characteristic features :-
-Submucosa ,with the mucous duodenal (Bruner,s ) glands.
-Covered with serosa and adventitia.

2- Ileum:Has a lamina propria , with abundant of lymphatic nodules, are known as (Peyer , s patches) .