The large intestine is also known as colon. It is a long continuous tube-like tract through which food residue passes before defecation. The colon begins as a dilated pouch, the caecum, to which appendix is attached. The large intestine does not take part in the digestion or the absorption of the food. The content that reaches the large intestine is devoid of nutrients. The large intestinal walls absorb the water in the residue and the soft-solid is passed towards the rectum. Peristalsis is very slow in the colon.
The rectum is the last portion of the large intestine. It is normally empty until just before defecation. In a person of regular habit the call to defecate occurs at about the same time each day. During defecation strong peristalsis occurs in the colon. The rectum acts as a temporary storage site for faeces, which expels solid waste through the anus.
The appendix is also known as the vermix. It is a pouch-like structure of tissues, located in the lower abdominal at the right-hand side. It resembles a worm. It is a narrow tube about four inches long. Its function is not known completely, but according to a few theories, it acts as a storehouse for storing good bacteria of the stomach.