About 1.5 meters long and thick part extending from the end of the ileum to the anus is called the large intestine. Here the food stays for 1.5-2.0 days. The large intestine has three parts.
Cecum, colon and rectum.
(i) Cecum: The first part of the large intestine is called the cecum. It is sac shaped. Its length is 6 cm and width is 7.5 cm. At the bottom of the caecum is a tube-like outgrowth. It is called vermiform appendix. Inflammation of the appendix caused by bacteria is called appendicitis. It is a passive organ.
(ii) Colon: The tubular portion after cecum is called colon. Its length is 101-114 cm. The colon has four parts. Ascending colon, transverse colon, descending colon and sigmoid colon.
(1) Ascending Colon: This part rises upwards from the cecum. Its length is 13 cm.
(2) Transverse Colon: This part lies transversely. Its length is 38 cm.
(3) Descending Colon: The part of the colon that is downward is called the descending colon. Its length is 25 cm.
(4) Sigmoid colon: The part of the colon connected to the rectum that forms a loop-like structure is called the sigmoid colon. Its length is 25-38 cm.
Function: Colon digests and absorbs food.
(iii) Colon: The sac-like part located at the end of the large intestine is called colon. The lower part of the rectum swells to form an ampulla. Its length is 13 cm. It contains annular sphincter or sphincter.
Functions: Faeces are produced in the large intestine, water is absorbed, food fermentation and digestion takes place.