
Does the appendix serve a purpose in any animal? (2001) - georgecmu
https://www.scientificamerican.com/article/does-the-appendix-serve-a/
======
killjoywashere
From a structure-function perspective, the human vermiform appendix is simpy
the terminus of the tiniae coli: the cords of smooth muscle have to end
somewhere. Similar "I gotta end somwhere" constructs are the gubernaculum and
the platysma. Appendices tend to have lots of lymphoid aggregates, but the
entire gut has lymphoid aggregates. The fact that more are in the appendix per
square inch of epithelium, is probably due as much to its dependent location
(everything in the right colon tends to fall down) as any developmental
specialization. I am also not aware of any appendix-specific transcription
factors (I think most pathologists would agree such a thing would be useful if
it existed, see Krukenberg tumor).

At a histologic level, there is nothing special about the appendix. The cell
types in the appendix are found throughout the colon: colonic epithelium,
smooth muscle, lymphoid tissue, vessels, nerves.

I think the term "vestigal" is being misinterpreted by many as a suggestion
that it had some more important function earlier in evolution. I rather doubt
it. They assert that an appendix hasn't been described in some species. Ok,
but have you positively described the absence of tiniae coli as well?

The association with the Bursa of Fabricius may hold water, because the bursa
apparently develops from the avian hindgut, however, unlike birds, when we
amputate the appendix of a baby human, it doesn't develop an immune
deficiency. Also, the bursa seems to be further down the gut than that
appendix, although I have not done a careful examination.

~~~
Lordarminius
> From a structure-function perspective, the human vermiform appendix is simpy
> the terminus of the tiniae coli ...

Are you an anatomist/pathologist ? Your post brings back memories of my med
school years :) I tend to agree with you - the appendix may be a vestigial
organ in the sense that it has a common derivation and serves an immunologic
purpose in evolutionary relatives, but we can posit that it may never have
done so in man

~~~
AstralStorm
You cam posit so and you would be very wrong. See first reply.

Also look up side effects of appendectomy on pubmed to see what functions it
has.

~~~
mywittyname
Care to provide a link? I did a search but the only results I found specified
stump appendicitis (infection of any leftover bits) and bowel obstructions.

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DoodleBuggy
This question has been answered many times through numerous studies since 2001

TLDR: Yes

[http://www.sciencedirect.com/science/article/pii/S1631068316...](http://www.sciencedirect.com/science/article/pii/S1631068316300653)

[http://dujs.dartmouth.edu/2008/04/a-bacterial-safe-house-
a-n...](http://dujs.dartmouth.edu/2008/04/a-bacterial-safe-house-a-new-role-
for-the-appendix/)

[https://www.sciencedaily.com/releases/2007/10/071008102334.h...](https://www.sciencedaily.com/releases/2007/10/071008102334.htm)

[http://time.com/4631305/appendicitis-appendix-gut-
bacteria/](http://time.com/4631305/appendicitis-appendix-gut-bacteria/)

------
dustfinger
The appendix protects good bacteria in the gut.
[https://www.wired.com/2013/02/appendix-
revolution/](https://www.wired.com/2013/02/appendix-revolution/)

------
Gustomaximus
It does for Koala's. There's probably better articles. This was the best of a
bad lot on a quick search:

[http://www.abc.net.au/news/2007-10-10/scientists-discover-
tr...](http://www.abc.net.au/news/2007-10-10/scientists-discover-true-
function-of-appendix-organ/693946)

