Search results
Results from the WOW.Com Content Network
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]
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 vomeronasal organ plays an important role with its sensitivity toward chemicals that are related to mating or sensing prey. For example, snakes use the organ to detect the presence of prey or predator by gathering chemical cues in the environment through the flicking behavior of the forked tongue.
This definition is consistent with Wiedersheim, who said that vestigial organs are "wholly or in part functionless" (Wiedersheim 1893, p. 200) and have "lost their original physiological significance" (p. 205). Although Wiedersheim's originally published list contains 86 items, later interpretations enlarged his list to 180 vestiges.
The twin reversed arterial perfusion, or T.R.A.P. sequence, results in an 'acardiac twin', a parasitic twin that fails to develop a head, arms and a heart.The parasitic twin, little more than a torso with or without legs, receives its blood supply from the host twin by means of an umbilical cord-like structure, much like a fetus in fetu, except the acardiac twin is outside the autosite's body.
The condition is also called parapagus dicephalus. [1] If carried to term, most dicephalic twins are stillborn, or die soon after birth. [3] A small number are known to have survived to adulthood. [3] The extent to which limbs and organs are duplicated varies from case to case.
Vestigial organ. Add languages. Add links. Article; Talk; ... Download QR code; Print/export Download as PDF; Printable version; In other projects