What Is ANAL CANAL? ANAL CANAL Definition & Meaning
Channel: Audiopedia
Date: 05/11/2018

what is anal canal, what does anal canal mean, anal canal meaning, anal canal definition, anal canal explanation

The anal canal is the terminal part of the large intestine.[1] It is situated between the rectum and anus,[2] below the level of the pelvic diaphragm. In humans it is approximately 2.5 to 4 cm (0.98-1.58 in) long. It lies in the anal triangle of perineum in between the right and left ischioanal fossa.

The anal canal is divided into three parts. The zona columnaris is the upper half of the canal and is lined by simple columnar epithelium. The lower half of the anal canal, below the pectinate line, is divided into two zones separated by Hilton's white line. The two parts are the zona hemorrhagica and zona cutanea, lined by stratified squamous non-keratinized and stratified squamous keratinized epithelium, respectively.

In humans it is approximately 2.5 to 4 cm long, extending from the anorectal junction to the anus. It is directed downwards and backwards. It is surrounded by inner involuntary and outer voluntary sphincters which keep the lumen closed in the form of an anteroposterior slit.

Behind this lies the anal gland which secretes lymphal discharge and built up fecal matter from the colon lining. Gland expungement is done routinely every 24 - 36 months to prevent infection and fistula formation.

It is differentiated from the rectum by the transition of the internal surface from endodermal to skinlike ectodermal tissue.
Source: Wikipedia.org