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In humans, the vermiform appendix is sometimes called a vestigial structure as it has lost much of its ancestral digestive function.. Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. [1]
Ileum, caecum and colon of rabbit, showing Appendix vermiformis on fully functional caecum The human vermiform appendix on the vestigial caecum. The appendix was once believed to be a vestige of a redundant organ that in ancestral species had digestive functions, much as it still does in extant species in which intestinal flora hydrolyze cellulose and similar indigestible plant materials. [10]
The appendix, long misunderstood as a vestigial organ, is now recognized as a key MALT structure, playing an essential role in B-lymphocyte-mediated immune responses, hosting extrathymically derived T-lymphocytes, regulating pathogens through its lymphatic vessels, and potentially producing early defenses against diseases. [1]
Vestigial structures are anatomical structures of organisms in a species which are considered to have lost much or all of their original function through evolution. [8] These body parts can be classed as additional to the required functioning of the body. In human anatomy, the vermiform appendix is sometimes classed as a vestigial remnant.
The longest appendix ever removed was 26 cm (10 in) long. [3] The appendix is usually located in the lower right quadrant of the abdomen, near the right hip bone. The base of the appendix is located 2 cm (0.79 in) beneath the ileocecal valve that separates the large intestine from the small
A Meckel's diverticulum, a true congenital diverticulum, is a slight bulge in the small intestine present at birth and a vestigial remnant of the vitelline duct.It is the most common malformation of the gastrointestinal tract and is present in approximately 2% of the population, [1] with males more frequently experiencing symptoms.
Inflamed appendix removal by open surgery Laparoscopic appendectomy. Laparoscopic view of a phlegmonous cecal appendix with fibrinous plaques, located in the right iliac fossa. The surgical procedure for the removal of the appendix is called an appendectomy. Appendectomy can be performed through open or laparoscopic surgery.
It is erroneous to cite the appendix as a vestigial organ when we now know that it serves a biological function (i.e. a reservoir for beneficial bacteria). The article first cites it as a vestigial organ, then equivocates, suggesting the appendix might have a purpose after all. That’s a poor example of a vestigial organ.