Function of the Appendix and Facts About Appendicitis
What Is the Appendix?
The appendix is a small, blind-ended tube that extends from a pouch called the cecum at the start of our large intestine. The lumen or cavity of the appendix is continuous with the lumen of the cecum. It’s long been assumed that the appendix is a vestigial structure—one that had a function in our distant ancestors but no longer has a function in our bodies. Some researchers think that the appendix does have some useful functions, however.
The appendix can create big problems if it becomes inflamed and swollen due to an infection by bacteria. This condition is known as appendicitis. It's often a very painful disorder and is potentially dangerous. If the appendix ruptures, it may release its contents into the abdomen. This may result in peritonitis, a very serious condition in which the lining of the abdomen is inflamed. The usual treatment for appendicitis is to remove the appendix.
The Human Digestive System
Location of the Appendix
The full name of the appendix is "vermiform appendix". Vermiform means worm-like, which is a good description for this organ. Its length varies considerably, but on average an adult appendix is 11 cm (4.3 inches) long and about 6 to 8 mm (0.24 to 0.32 inches) in diameter.
The colon is the first and longest part of our large intestine. It has three sections—the ascending colon, which is connected to the small intestine, the transverse colon, and the descending colon. The cecum and the appendix are located at the start of the ascending colon and are found in the lower right area of the abdomen (from the patient's point of view).
The cecum serves no special function in humans. In herbivorous animals, bacteria in the enlarged cecum break down the cellulose present in the cell walls of plants.
Not all mammals have an appendix, but some do. This adds to the mystery of its evolution and possible function. Mammals with an appendix include humans, great apes, wombats, opossums, and rabbits.
Some Possible Functions of the Appendix
The human appendix may have one or more functions. Some leading theories are listed below.
- According to Loren G. Martin, a physiology professor at Oklahoma State University, endocrine cells (cells that produce hormones) appear in the appendix of a human fetus at about eleven weeks of development. The endocrine cells are active and release hormones. Hormones are chemical messengers and have specific effects in our bodies.
- The lining of the appendix contains lymphoid tissue, which is part of our immune system. The immune system fights bacteria and other organisms that cause disease. We have lymphoid tissue in many other areas of the body in addition to the appendix.
- One theory is that antigens (particles from invading organisms) enter the appendix from the intestine and cause the cells in the lymphoid tissue to make antibodies. These antibodies then protect us when we are exposed to the antigens in the future. According to this theory, the appendix is acting as a training ground for the immune system.
Protection for Good Bacteria and a Ureter Replacement
- It's been proposed that the appendix is a type of safe house for good bacteria that live in the large intestine. These bacteria are important for our health. According to the proposal, if bacteria in the large intestine are lost for some reason—such as in disease or antibiotic treatment—or if the intestine is invaded by bad bacteria that kill the good ones, the appendix can "reboot" the large intestine. It does this by releasing good bacteria to recolonize the large intestine. Some scientists have criticized this idea, saying that although the appendix can send bacteria back into the intestine, it sends bad bacteria as well as good bacteria.
- The appendix is occasionally used for surgical reconstruction of damaged structures in the body, such as a ureter (the tube that transport urine out of the kidney to the urinary bladder) in young children. This is not a natural function of the appendix, but it's certainly useful.
The theories describing possible appendix functions are very interesting, but they need to be confirmed by more scientists. If the theories are true, we need to know whether the actions of the appendix are insignificant because they are also performed by other parts of our body or if they are actually important.
An Appendicitis Overview
Causes of Appendicitis
The word "appendicitis" mean "inflammation of the appendix". It's not always clear why this inflammation develops. The problem may begin when the opening to the appendix is blocked by mucus produced inside the appendix or by feces moving through the colon. The feces may become hard, forming a fecal stone that traps bacteria inside the appendix.
Trapped bacteria reproduce and their population increases, since they can't escape into the colon. The bacteria trigger the inflammatory response, which is the body's way of fighting infection and damage to the body. Pus and fluid build up during this response, causing the appendix to swell and become painful.
The appendix may also become blocked when its lymphoid tissue swells due to a gastrointestinal infection or an infection somewhere else in the body. In addition, the entrance to the appendix may be blocked by an abnormal growth of tissue. Rarely, appendicitis develops because of trauma to the abdomen.
A Doctor Describes Appendicitis Symptoms
The most noticeable symptom of appendicitis is generally pain.
- The first symptom of the problem is usually a dull pain near the naval. The pain is often diffuse and isn't localized in any one area.
- This pain gradually moves to the lower right quadrant of the abdomen and becomes more severe.
- Pain become worse as time passes.
- Pain is felt when the lower right abdomen is pressed. (This should always be done very gently!)
- Pain is felt when the hand that was pressing the abdomen is released (rebound tenderness).
- Pain is worse when a person coughs, walks or moves.
These symptoms may be caused by other conditions besides appendicitis. A doctor must be consulted for a diagnosis.
Other Possible Symptoms
Other symptoms of appendicitis may include the following:
- nausea and vomiting
- loss of appetite
- abdominal swelling
- diarrhea or constipation
- inability to pass gas
The symptoms of appendicitis are shared with other disorders, so a doctor will often perform diagnostic tests before the appendix is removed.
Appendicitis can't be self-diagnosed or treated with herbal medicine. Someone with symptoms that might indicate the existence of appendicitis must visit a doctor for a diagnosis and treatment. A ruptured appendix is a very dangerous condition.
An Appendicitis Poll
Have you had appendicitis?
Some Possible Treatments
A person with appendicitis shouldn't refuse to get their appendix removed if this is recommended by a doctor. They will probably be in too much pain to consider refusing the surgery, anyway! It's probably not a good idea to remove a healthy appendix, however, even though a person can live an apparently normal life without it. The appendix may have hidden benefits.
It used to be a common procedure to remove the appendix during abdominal surgery for another problem. This was believed to be a wise move, since it was thought that we didn't need the appendix and its removal would prevent the development of appendicitis in the future. Removing a healthy appendix is no longer a routine procedure.
People with severe lower abdominal pain need to get a prompt medical examination. An appendectomy or appendicectomy (surgery to remove the appendix) is usually straight forward and the patient recovers quickly. If an infected appendix ruptures, pus and fluid may collect near the appendix. Surgeons can drain this fluid from the body. If pus inflames the membrane lining the abdomen, which is called the peritoneum, doctors have to use aggressive treatment to cure the infection. Peritonitis may be life threatening.
Appendicitis is most common in people between the ages of ten and thirty but can occur at any age.
Antibiotic Treatment for Uncomplicated Appendicitis
In some cases of uncomplicated appendicitis (cases in which the appendix hasn't ruptured), antibiotics have cured the infection and surgery hasn't been necessary. A delay in surgery while antibiotics are tried worries some doctors, however. They are afraid that if the antibiotics don't work the appendix could continue to swell and eventually rupture.
In some people who are weakened by another illness, surgery may be risky. Doctors sometimes try antibiotics as a first approach to treating appendicitis in these people. It's very important that anyone who receives antibiotic treatment for an inflamed appendix is monitored closely by their doctor. There seems to be a 10% to 20% risk of recurrence of appendicitis after apparently successful antibiotic treatment.
In this article, the word "appendicitis" refers to an acute condition which appears quickly and has dramatic symptoms. There is another, much rarer form of the disorder known as chronic appendicitis. This is a long-lasting condition with milder symptoms. Antibiotics are most likely to be tried as a treatment for this type of appendicitis.
Can Appendicitis Be Prevented?
There is no known way to prevent appendicitis, although eating a diet that is high in fibre may reduce the risk. Fibre is found in foods from plants, so eating lots of grains, legumes (also known as pulses), vegetables, and fruit would create a high fibre diet.
In 1986, researchers explored the link between acute appendicitis and diet in 59 areas of Britain. They found a positive correlation between potatoes and appendicitis but a negative one between green vegetables and appendicitis. This is an old study and really needs to be repeated. Since green vegetables are known to have many health benefits besides possibly reducing the risk of appendicitis, however, it's a good idea to include lots of them in the diet.
Most of us are never aware of our appendix. It never causes problems and may even be helping us. When a problem with the organ does occur, however, it's generally very noticeable. Fortunately, an effective treatment is available.
- The Appendix as a Safe House for Bacteria from NBC news
- A Possible Function of the Appendix from ScienceDaily
- Antibiotics and Appendicitis: University of Nottingham Report from WebMD.com
- Antibiotics and Appendicitis: University of Gothenburg Report from ScienceDaily
- Vegetable Consumption and Acute Appendicitis from the NIH (National Institutes of Health)
© 2013 Linda Crampton