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In human anatomy, the vermiform appendix (or appendix, pl. appendices) is a blind ended tube connected to the cecum (or internationally, "caecum"). It develops embryologically from the cecum. The term vermiform comes from Latin and means "wormlike in appearance". The cecum is the first pouch-like structure of the colon. The appendix is near the junction of the small intestines and large intestines.
Size and location The appendix averages 10 cm in length, but can range from 2-20 cm. The diameter of the appendix is usually less than 7-8 mm. The longest appendix ever removed was that of a Pakistani man on June 11, 2003, at Pakistan Institute of Medical Sciences, Islamabad, measuring 23.5 cm (9.2 in) in length. While the base of the appendix is at a fairly constant location, the location of the tip of the appendix can vary from being retrocaecal to being in the pelvis to being extraperitoneal. In most people, the appendix is located at the lower right quadrant of the abdomen. In people with situs inversus, the appendix may be located in the lower left side. Function Currently, the function of the appendix, if any, remains controversial in the field of human physiology. It has been known to cause the ability to process bark, leaves and other things of that nature. There have been cases of people who have been found, usually on laparoscopy or laparotomy, to have a congenital absence of their appendix. There have been no reports of impaired immune or gastrointestinal function in these people. One explanation has been that the appendix is a vestigial structure with no current purpose. The appendix is thought to have descended from an organ in our distant herbivorous ancestors called the cecum (or caecum). The cecum is maintained in modern herbivores, where it houses the bacteria that digest cellulose, a chemically tough carbohydrate that these animals could not otherwise utilize. The human appendix contains no significant number of these bacteria, and cellulose is indigestible to us. It seems likely that the appendix lost this function before our ancestors became recognizably human. Diseases The most common diseases of the appendix (in humans) are appendicitis and carcinoid. An operation to remove the appendix is an appendicectomy (also appendectomy). | |||||||||||||||||||||||||||||||||||
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