What Does The Human Appendix Do?

Picture courtesy of cancer.gov
Picture courtesy of cancer.gov
Vermiform Appendix (highlighted in box) - Gray's Anatomy, 1918 (with modifications).
Vermiform Appendix (highlighted in box) - Gray's Anatomy, 1918 (with modifications).

The Appendix

The appendix is a narrow, muscular, worm-shaped tube. One end is attached to the first part of the large intestine. The other end is closed and its position in the body can vary from person to person.

An average adult appendix is about 4 inches (10cm) long, but can range in length from less than an inch up to 8 inches. Its diameter is usually about 1/3 inch (7-8mm).

The function of the appendix is unknown.

Indigestible food moves from the small intestine into the appendix, and is then forced out again, as the appendix contracts its muscular walls, into the large intestine.

Because of this action, the most popular theory is that it was once used by primitive man to digest particularly tough foods, but is no longer required in modern man as we have a different diet.

Scientists have also theorized that the appendix may have lympatic, exocrine, endocrine, or neuromuscular functions.

The appendix can be surgically removed (appendectomy) without any known side effects. The usual reason for removal of the appendix is appendicitis, where the appendix becomes inflamed.

Recognizing & Treating Appendicitis

Location of the Appendix

Did You Know ... ?

  • The Australian koala has an appendix which is over 6 foot or 2 metres long! This animal eats eucalyptus leaves, which it is thought are detoxified in its appendix.
  • Most cases of appendicitis are in people aged between 8 and 25. It is rarely seen in children under 2 years old.
  • According to Guinness world records, the longest appendix ever removed was 9.2 inches (23.5cm) in length, from a man in Pakistan in 2003.
  • A person's age can be estimated by the appearance of the lymph nodules in the appendix. At birth, lymphoid nodules are not present; but by age 10 there are many throughout the mucosa of the appendix. After the age of 10, the lymphoid nodules gradually waste away. By the age of 40, the lymph nodules are barely visible.

© 2008 fridayonmymind

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Comments 30 comments

chloe 6 years ago

my friend is in the emergency room because of her appendix


fridayonmymind profile image

fridayonmymind 6 years ago Author

Sorry to hear that. I hope your friend recovers quickly.


e-lyl 6 years ago

Nice hub, thanks.

I think I read recently in SciAm that some researchers think the appendix acts as a reservoir for intestinal flora. After a bout of diarrea the gut can be reinocuclated by the bugs stored in the appendix.

Interesting theory anyway.


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fridayonmymind 6 years ago Author

Very interesting. Thanks for posting it!


J.T. Schuster profile image

J.T. Schuster 6 years ago from Murfreesboro TN

I have this theory that my half brother still uses his for eating all of the raw meats that he does...lol.


Salena 6 years ago

Had my appendix taken out a year ago. It's awful pain to go through.


nicky 6 years ago

i had appendix


lg 5 years ago

my sister has just had hers out she is in pain


Ben 5 years ago

Right now my brother's in the hospital too and his appendix is gonna be taken out. That's why I looked this up to begin with. (and nicky everyone "had" an appendix...?)


Donna 5 years ago

While reading about the appendix on your site, I noticed the author uses the term "man" to refer to all humans. The creditability of the information is called into question when out-dated terms are used. Please rectify.


Rebecca 5 years ago

Just had mine taken out, very painful stuff.


Ashlei 5 years ago

My brothers girlfriend is in the hospital now because hers broke.

And donna I think you just don't like it because your sexist.


Chance 5 years ago

I had mine removed on Monday and returned to work the following Monday...But yes i agree, very painful stuff!


fridayonmymind profile image

fridayonmymind 5 years ago Author

Thanks for your comments! Hey Donna, when did the word "man" as a generic term for all humans become "out-dated"? It's in every dictionary! In fact, I looked up "human" in the dictionary, and it said "relating to man and mankind".


Annelli 5 years ago

I had my appendix out last week and still in pain. Man is a term used for women, men and children it is as modern today as it was 150yrs ago. I hope know one see's this topic as sexist because that would be pathetic.


me 5 years ago

you are all stupid. =) in a nice way. no one likes appendixes hahahahahaha.


Francisco 5 years ago

My appendix was inflamed and I had to sit in the waiting hall in pain for over 13 hours until I was finally attended but,before I went to the hospital I was throwing up for a week! Worst time of my life...anyway im glad that surgery wont affect me in anyway although full recovery can take a while.


Alicia 5 years ago

On how the theory of how the appendix stopped working..."The appendix no longer functions because primitive man ate 'tough foods'" seems silly. When a man stops eating tough foods this doesn't cause the appendix to stop working. The appendix would have stopped working because some man had a non-working appendix while another man had one that was still working. The working appendixes could have been bad for man and soon after they died. Those who had the non-working appendixes still lived and the genetics of the non-working appendix runs through modern man.

Anyways! Great article! very useful for my project!


Martin 4 years ago

@ Donna

I realize this is nine months later and you likely won't see it, but please stuff your feminazi gender neutral crap.

The word "man" has been used as shorthand for "human" throughout the entirety of human history. Don't expect *man* to bow down to your demand to change simply because you've got your panties in a wad.

A demand on your part doesn't necessitate a change on ours.


NinoG 4 years ago

I like the way we used to be...When woMAN let man be MAN. Knock off your silly pro-WOman attitude Donna. Everyone knows that author was referring to Mankind. You're putting women back in place that 1000's fought hard to get out of. Just the fact that you feel the need to take the authors words out of context and make this about yourself, proves that truly don't understand what the 1000's were and still are striving for. Deep breath. Deep breath Donna....you'll live on Sister.


lily 4 years ago

my sister got her appendix taken out last week and mine is coming out in eight days.


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fridayonmymind 4 years ago Author

Best wishes to you both!


cade 4 years ago

The apprndix MUST be of some use, I know this as a fact, if it is of surely no use evolution should've disapeared millions of years ago


bananaman 4 years ago

Mine had to come out 2 years ago now. Since having it out I've developed Irritable Bowel Syndrome. I don't think they are unrelated, so I do think the appendix does something we haven't fully appreciated yet.


Christina 4 years ago

I read the appendix is used still,especially in babies and young children, for immune response. Certain white blood cells, immunoglobulin, are stored there and it tells them where to go.


mike 4 years ago

veryy painfull cant git out of bed strugglling day 3 out of hospital


guddu 3 years ago

My mother has a appendix of about 8mm we should operate or cure by medicine


fridayonmymind profile image

fridayonmymind 3 years ago Author

I recommend always seeing a doctor if you're worried about anything medical.


A.H 3 years ago

SEE always doctor help,its not so simple,matter of s life


W.L 2 years ago

http://www.news-medical.net/news/2007/10/08/30907....

Researchers at Duke University Medical Center say that the function of the frequently discarded appendix, an organ often credited with little importance and often dismissed as having no significant function, does it seems have a role to play after all.

Researchers in the United States say the appendix produces and protects good germs for the gut by "rebooting" the digestive system.

The team of immunologists at Duke University Medical Center say the human digestive system contains massive amounts of bacteria most of which are good and help the digestion of food.

However the researchers say sometimes the bacteria die off or are purged from the intestines as in diseases such as cholera or dysentery.

According to the researchers, the appendix's job is to "reboot" the digestive system when that happens with the bacteria safely harbored in the appendix.

Many doctors believe the appendix is a vestigial organ with no function and is no more than a blind ended tube connected to the cecum, from which it develops embryologically.

The cecum is a pouch-like structure of the colon and the appendix is near the junction of the small intestine and the large intestine and has abundant infection-fighting lymphoid cells, which suggests it plays a role in the immune system.

The most common diseases of the appendix (in humans) are appendicitis and carcinoid tumors. Appendix cancer accounts for about 1 in 200 of all gastrointestinal malignancies.

Appendicitis is a condition where the the appendix becomes inflamed and in almost all cases it is removed either by laparotomy or laparoscopy; left untreated, the appendix will rupture, leading to peritonitis, then shock, and, if continued untreated, death.

The appendix is routinely removed without any notable ill effects or side effects and the scientists stress that even though the appendix seems to have a function, people should still have them removed when they are inflamed because since leaving it untreated could be fatal.

Dr. Bill Parker, a professor of surgery and one of the scientists responsible for establishing its status as a useful organ, says the function of the appendix seems related to the massive amount of bacteria that populates the human digestive system and where it is located just below the normal one-way flow of food and germs in the large intestine, helps support that theory.

The study appears in the online edition of the Journal of Theoretical Biology.

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