What are the main functions of the large intestine?

The large intestine has four key functions: absorption of water to form feces; storage, lubrication, and expulsion of fecal matter; synthesis of vitamin B-complex by gut flora; and protection via mucoid secretion rich in IgA antibodies.

What are the parts of the large intestine?

The large intestine consists of four main regions: caecum and appendix, colon (ascending, transverse, descending, and sigmoid), rectum, and anal canal.

How can you distinguish the large intestine from the small intestine anatomically?

The large intestine has three unique anatomical features: teniae coli (longitudinal muscle bands), appendices epiploicae (fat-filled peritoneal tags), and sacculations (haustrations) (outpouchings of the wall). These are absent in the small intestine.

What are the layers of the colon wall?

The colon wall has four layers: mucosa (lacks villi, has goblet cells), submucosa (contains vessels and Meissner’s plexus), muscle layer (inner circular and outer longitudinal with teniae coli), and serosa (covers transverse and sigmoid colon).

Which parts of the large intestine are intraperitoneal and mobile?

Only the appendix, transverse colon, and sigmoid colon are intraperitoneal with mesenteries, making them mobile. The rest of the large intestine is more fixed.

What are teniae coli and where are they found?

Teniae coli are three longitudinal muscle bands (tenia libera, tenia mesocolica, tenia omentalis) in the colon's outer layer. They converge at the appendix base and disappear at the rectum, contributing to sacculations.

Large Intestine – Parts & Key Features (Teniae, Haustra)