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Anatomy photo:37:12-0102 at the SUNY Downstate Medical Center—"Abdominal Cavity: The Cecum and the Vermiform Appendix" "The vestigiality of the human vermiform appendix: A Modern Reappraisal"—evolutionary biology argument that the appendix is vestigial; Smith HF, Fisher RE, Everett ML, Thomas AD, Bollinger RR, Parker W (October 2009).
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]
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]
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]
Coming off the side of the cecum (the tiny tail piece) is the appendix. It is a small organ attached to the large intestine in the lower right side of the abdomen. Anatomists and medical professionals have traditionally considered the appendix a vestigial organ. Later research suggests that it may have an immunological function. [13]
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.
Epoöphoron formed from the upper part of the mesonephric body. b. Remains of the uppermost tubes sometimes forming appendices. c. Middle set of tubes. d. Some lower atrophied tubes. e. Atrophied remains of the mesonephric duct. f. The terminal bulb or hydatid. h. The uterine tube, originally the duct of Müller. i. Appendix attached to the ...
Although structures called vestigial often appear functionless, a vestigial structure may retain lesser functions or develop minor new ones." I think the connection made between appendix and vestigial organs is therefore wrong, because vestigial organs can have function and still remain vestigial.