Download The Large Intestine Location: The large intestine lies inferior to the

 The Large Intestine
 Location: The large intestine lies inferior to the stomach and liver
 Functions:
1. Reabsorb water and compact material into feces.
2. Absorb vitamins produced by bacteria.
3. Store fecal matter prior to defecation.
 Division:
1. Cecum and Appendix: the first portion of the large intestine.
2. Colon (ascending, transverse, descending, sigmoid): the largest portion.
3. Rectum: the last of the large intestine lead to the end of the digestive tract
(anal canal).
 Histology of Large intestine
1. Mucosa simple columnar epithelial with abundant goblet cells; stratified
squamous epithelium near anal canal.
2. No villi.
3. Large lymphoid nodules are scattered throughout the lamina propria and
submucosa.
Longitudinal muscle layer incomplete, forms three bands or taeniae coli. .4
5. Circular muscle forms pockets or haustra between bands.
6. The adventitia forms small pouches (appendices epiploicae) filled with fatty
tissue along the large intestine.
 Cecum and Appendix:
1. Cecum is the cavity in which the large intestine begins and into which the
ileum opens.
2. The cecum collects and stores materials from the ileum and begins the process
of compaction.
3. The slender, hollow appendix, or vermiform appendix, is attached to the poster
medial surface of the cecum.
4. appendix has thick wall, which is mainly due to large accumulations of
lymphoid tissue in the lamina propria and submucosa.
5. Intestinal villi are usually absent.
6. The muscularis externa is thinner.
7. The outer, longitudinal smooth muscle layer of the muscularis externa does
not aggregate into taeniae coli.
8. the primary function of the appendix is as an organ of the lymphatic system.
 Colon:
1. The wall of the colon forms a series of pouches, or haustra which permit the
expansion and elongation of the colon.
2. Crypts of Lieberkühn are present.
3. Villi are absent and Goblet cells are numerous.
4. The lamina propria and muscularis mucosae may be difficult to distinguish.
5. Three separate longitudinal bands of smooth muscle called the taeniae coli.
 Rectum:
1. Epithelial type is keratinized stratified squamous.
2. The last portion of the rectum, the anal canal, contains small longitudinal folds
called anal columns.
3. The anus is the exit of the anal canal. where the epidermis becomes
keratinized.
4. Rectum has internal involuntary sphincter and external voluntary sphincter
which guards the anus.
5. Rectum is a retroperitoneal.
Type of gland is mucus (mucous glands)