Biology 106

Digestive system

Stomach

Ileum

StomachT.S. of the stomach of rabbit

• The tube wall in General made up of 4 layersFrom the outer layer to the inner:1. Serosa : (Simple squamous epithelium)2. Muscularis: (L.M.L and C.M.L)3. Submucosa: (C.T. ,B.V., muscularis mucosa layer)4. Mucosa: (simple tubular glands; have 3 cell types:

a- Simple columnar cells, b-Peptic cells secrete digestive enzyme, c-Oxyntic cells secrete HCL.

Serosa

• It composed of very thin layers of loose connective tissue+(Simple squamous epithelium)

Muscularis• Composed of

smooth muscle fibers

Longitudinal external layer (L.M.L.)

Circular inner layer (C.M.L)

Submucosa

• Consists of loose connective tissue, blood and lymph vessels.

• It is a very light area.

The mucosaThe thickest layer, consists of :A. Layer of simple

columnar epithelium+ Gastric gland

B. the muscularis mucosae consists of :

An inner circular smooth muscle fibers

An outer longitudinal smooth muscle fiber + blood vessels.

Gastric glands have 4 types:Two of them are well distinguished 1- peptic cells secrete digestive enzymes2- oxyntic cells secrete HCL

Ileum is the smallest part of samll intestineT.S. of the ileum of rabbit

• The tube wall in General made up of 4 layersFrom the outer layer to the inner:1. Serosa : (Simple squamous epithelium)2. Muscularis: (L.M.L and C.M.L)3. Submucosa: (C.T. ,B.V., muscularis mucosa

layer)4. Mucosa: intestinal villi and crypts of

Lieberkuhn lined with simple columnar and globlet cells (secrete mucous)

Hisology: T.S. of the ileum of rabbit

Mucosa• Intestinal villi increase

intestinal absorptive surface , Villi also help the intestines to move food along the digestive pathways.

• Crypts, Intestinal glands are located in the crypts of Lieberkuhn at the base of the villus .

Liver• The liver is the body's largest compound

gland. It is a major metabolic organ, and is important for degrading alcohol and drugs.

T.S. of the liver of the pig

• A reticular gland formed of the cells arranged in strands crossing each other forming network

• The strands form hepatic lobules

• Each lobules has a central vein and blood sinusoids.

• Among these lobules there are C.T. and many portal spaces.

• Each portal space contains branch of portal vein, branch of hepatic artery and bile ductule.

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