What Is the Appendix? A Vestigial Organ, or One With a Purpose?
Apr 07, · Your appendix is a 4-inch-long tube. It’s attached to the first part of your large intestine. Its exact function is unclear. Some people believe that it’s an evolutionary holdover that provides no Author: Elizabeth Connor. May 30, · The appendix is a thin, roughly four-inch-long tube that's part of your gastrointestinal (GI) tract. (1) The GI tract is a complex group of organs, each of which helps your body digest and absorb.
The role of the appendix has long been something of qhat mystery, but some experts now believe they've finally appwndix its function. The appendix is a thin, roughly four-inch-long tube that's part of your gastrointestinal GI tract.
The GI tract is a complex group of organs, each of which helps your body digest and absorb food. Your upper GI ia includes your esophagus, stomach, and the first section of your small intestine, called the duodenum. The lower GI tract is made up of most of your small intestine and all of your large intestine, which includes your colon, rectum, and anal canal.
Your appendix is located in the lower right part of your abdomen, in an area that doctors refer to as McBurney's point. If applying pressure on McBurney's appehdix results in pain how to dress 24 years old tenderness, your doctor may suspect that you have appendicitis.
The finger-shaped appendix is attached to a part of your large intestine called the cecum — a small pouch typically considered to be the beginning of the large intestine. The muscles lining your GI tract, along with the what is the state of the union speech and enzymes that the system produces, allow your GI tract to break down and process food.
Your appendix doesn't directly help with digestion. It's been unclear what role the appendix has in the body, and removal of the organ doesn't whar to have any negative health consequences. For many years, scientists believed the appendix was a vestigial organ — one that lost its appednix function through centuries of evolution.
Wbat thought that no other mammals had an appndix, aside from our closest ape relatives. What's more, appehdix cecum of plant-eating aappendix is far larger do what you do marz album it is in humans. On this basis, Charles Darwin theorized that our distant ancestors also had large ceca, which allowed them to dine on leaves like the herbivores of today.
But as these ancestors shifted to a diet based on fruits, which are what makes meth labs explode to digest, their ceca shrank. The appendix, Darwin believed, is just a shriveled up part of the cecum, which evolution hasn't entirely eliminated. Some scientists now believe the appendix is not useless after all, and may help our guts recover after a gastrointestinal disease strikes.
The appendix contains a particular type of tissue associated with the lymphatic system, which carries the white blood cells needed to fight infections. In recent years, scientists have what is your appendix do that lymphatic tissue encourages the growth of some beneficial gut bacteria, which play an important role in human digestion and immunity. Studies have also shown that the lining of the gut contains a biofilm, or a thin layer of microbes, mucusand immune system molecules — and these biofilms appear to be most pronounced in the appendix.
According to the so-called "safe house" theory, the appendix protects a collection of beneficial gut bacteria when certain diseases wipe them out from elsewhere in the GI tract. Once the immune system has rid the body of the infection, the bacteria emerge from the appendix biofilm and recolonize the yoir. Researchers have recently found that numerous animals, including great apes, other primates, opossums, wombats, rabbits, and certain rodents all have structures similar to the appendix.
Sometimes, the appendix can become inflamed and infected, resulting in a condition called appendicitis. Appendicitis what will a neurologist do often the result of an abdominal infection that has spread to the tiny organ, or some kind of obstruction that has blocked hwat small opening of the appendix.
Sources of blockage include, dl other things:. The infection or obstruction causes the bacteria in the appendix to grow out of control, and the organ can fill with pus and swell.
Appendicitis causes intense abdominal pain and other GI symptoms, including vomiting and diarrhea. Removal of the appendix an appendectomy is often the ls course of action, though increasingly, antibiotics may be recommended and used to treat the infection without the need for surgical intervention — depending on the severity of the case and other health factors in the individual patient.
If the problem is left untreated, the pressure in the organ will increase until the appendix rupturesor bursts. When the appendix bursts, it spreads its content throughout the abdomen, potentially infecting the peritoneum, which is the silk-like membrane that lines the abdominal cavity.
Appndix 'Safe House' Theory of the Appendix Some scientists now believe the appendix is not useless after all, and may help our guts recover after a gastrointestinal disease strikes. Sources of blockage include, among other things: Hard pieces of stool Parasites or intestinal worms Ingested objects, including air gun pellets and pins Abdominal trauma GI tract ulcers Enlarged appemdix lymphatic tissue The infection or obstruction causes the bacteria in the appendix to grow out of control, and the organ can fill with pus and swell.
Editorial Sources and Fact-Checking. Appendix Anatomy. Encyclopaedia Brittanica. December April 30, Appendix Evolved More Than 30 Times. February 12, Journal of Theoretical Biology. January 15, Clinical and Experimental Immunology. October The Guardian. Appwndix 3, Mayo Clinic. May 16,
Sep 12, · As an adult, the appendix actually serves a number of important functions, provided it remains healthy. First and foremost, the appendix is a great storehouse for lymphocyte tissues, and throughout the majority of your life, the appendix aids in the production of certain lymphocytes, which are a type of white blood elvalladolid.comted Reading Time: 5 mins. Nov 24, · Normally, the appendix sits in the lower right abdomen. The function of the appendix is unknown. One theory is that the appendix acts as a storehouse for good bacteria, “rebooting” the digestive Estimated Reading Time: 2 mins.
The appendix or vermiform appendix ; also cecal [or caecal ] appendix ; vermix ; or vermiform process is a finger-like, blind-ended tube connected to the cecum , from which it develops in the embryo. The cecum is a pouch-like structure of the colon , located at the junction of the small and the large intestines. The term " vermiform " comes from Latin and means "worm-shaped.
In particular, it may serve as a reservoir for beneficial gut bacteria. The human appendix averages 9 cm 3. The diameter of the appendix is 6 mm 0. The longest appendix ever removed was 26 cm 10 in long. The base of the appendix is located 2 cm 0. Its position within the abdomen corresponds to a point on the surface known as McBurney's point. The appendix is connected to the mesentery in the lower region of the ileum , by a short region of the mesocolon known as the mesoappendix.
Some identical twins—known as mirror image twins —can have a mirror-imaged anatomy , a congenital condition with the appendix located in the lower left quadrant of the abdomen. While the base of the appendix is typically located 2 cm 0.
In very rare cases, the appendix may not be present at all laparotomies for suspected appendicitis have given a frequency of 1 in , Sometimes there is a semi-circular fold of mucous membrane at the opening of the appendix. This valve of the vermiform appendix is also called Gerlach's valve. Although it has been long accepted that the immune tissue surrounding the appendix and elsewhere in the gut—called gut-associated lymphoid tissue —carries out a number of important functions, explanations were lacking for the distinctive shape of the appendix and its apparent lack of specific importance and function as judged by an absence of side effects following its removal.
William Parker, Randy Bollinger, and colleagues at Duke University proposed in that the appendix serves as a haven for useful bacteria when illness flushes the bacteria from the rest of the intestines. Research performed at Winthrop—University Hospital showed that individuals without an appendix were four times as likely to have a recurrence of Clostridium difficile colitis.
The appendix has been identified as an important component of mammalian mucosal immune function , particularly B cell -mediated immune responses and extrathymically derived T cells. This structure helps in the proper movement and removal of waste matter in the digestive system, contains lymphatic vessels that regulate pathogens, and lastly, might even produce early defences that prevent deadly diseases.
Additionally, it is thought that this may provide more immune defences from invading pathogens and getting the lymphatic system's B and T cells to fight the viruses and bacteria that infect that portion of the bowel and training them so that immune responses are targeted and more able to reliably and less dangerously fight off pathogens.
Common diseases of the appendix in humans are appendicitis and carcinoid tumors appendiceal carcinoid. In rare cases, adenomas are also present. Appendicitis is a condition characterized by inflammation of the appendix. Pain often begins in the center of the abdomen, corresponding to the appendix's development as part of the embryonic midgut.
This pain is typically a dull, poorly localized, visceral pain. As the inflammation progresses, the pain begins to localize more clearly to the right lower quadrant, as the peritoneum becomes inflamed. This peritoneal inflammation, or peritonitis , results in rebound tenderness pain upon removal of pressure rather than application of pressure. Typically, point skin pain is not present until the parietal peritoneum is inflamed, as well.
Fever and an immune system response are also characteristic of appendicitis. Appendicitis usually requires the removal of the inflamed appendix, in an appendectomy either by laparotomy or laparoscopy. Untreated, the appendix may rupture, leading to peritonitis , followed by shock, and, if still untreated, death.
Recently, practitioners reported good results in treating appendicitis without appendectomy. Managing appendicitis using only antibiotic treatment and cooling of the appendix was successful in first occurrence acute appendicitis without complication. The surgical removal of the appendix is called an appendectomy. This removal is normally performed as an emergency procedure when the patient is suffering from acute appendicitis.
In the absence of surgical facilities, intravenous antibiotics are used to delay or avoid the onset of sepsis. In some cases, the appendicitis resolves completely; more often, an inflammatory mass forms around the appendix. This is a relative contraindication to surgery. The appendix is also used for the construction of an efferent urinary conduit, in an operation known as the Mitrofanoff procedure ,  in people with a neurogenic bladder. The appendix is also used as a means to access the colon in children with paralysed bowels or major rectal sphincter problems.
Charles Darwin suggested that the appendix was mainly used by earlier hominids for digesting fibrous vegetation, then evolved to take on a new purpose over time. The very long cecum of some herbivorous animals, such as in the horse or the koala , appears to support this hypothesis.
The koala's cecum enables it to host bacteria that specifically help to break down cellulose. Human ancestors may have also relied upon this system when they lived on a diet rich in foliage.
As people began to eat more easily digested foods, they may have become less reliant on cellulose-rich plants for energy. As the cecum became less necessary for digestion, mutations that were previously deleterious and would have hindered evolutionary progress were no longer important, so the mutations survived. It is suggested that these alleles became more frequent and the cecum continued to shrink.
After millions of years, the once-necessary cecum degraded to be the appendix of modern humans. Heather F. Smith of Midwestern University and colleagues explained:. This function is potentially a selective force for the evolution and maintenance of the appendix. Three morphotypes of cecal-appendices can be described among mammals based primarily on the shape of the cecum: a distinct appendix branching from a rounded or sac-like cecum as in many primate species , an appendix located at the apex of a long and voluminous cecum as in the rabbit, greater glider and Cape dune mole rat , and an appendix in the absence of a pronounced cecum as in the wombat.
In addition, long narrow appendix-like structures are found in mammals that either lack an apparent cecum as in monotremes or lack a distinct junction between the cecum and appendix-like structure as in the koala. A cecal appendix has evolved independently at least twice, and apparently represents yet another example of convergence in morphology between Australian marsupials and placentals in the rest of the world.
Although the appendix has apparently been lost by numerous species, it has also been maintained for more than 80 million years in at least one clade. In a paper, the appendix was found to have evolved at least 32 times and perhaps as many as 38 times and to have been lost no more than six times.
This complex evolutionary history of the appendix, along with a great heterogeneity in its evolutionary rate in various taxa, suggests that it is a recurrent trait.
Such a function may be useful in a culture lacking modern sanitation and healthcare practice, where diarrhea may be prevalent. Current epidemiological data on the cause of death in developed countries collected by the World Health Organization in show that acute diarrhea is now the fourth leading cause of disease-related death in developing countries data summarized by The Bill and Melinda Gates Foundation.
Two of the other leading causes of death are expected to have exerted limited or no selection pressure. Ileo-cecal valve and vermiform appendix. Mucinous adenocarcinoma of the appendix tip. Micrograph of entry point of appendicular arteries arrows at level of inner muscular layer , not to be confused with a perforation.
From Wikipedia, the free encyclopedia. Blind-ended tube connected to the cecum, from which it develops embryologically. For other uses, see Appendix disambiguation.
Drawing of colon with variability of appendix locations as seen from front. Arteries of cecum and appendix appendix labeled as vermiform process at lower right. Main article: Appendicitis. Main article: Appendectomy. Normal location of the appendix relative to other organs of the digestive system frontal view. Clinical and Experimental Immunology. PMC PMID Guinness World Records. Archived from the original on 26 November Retrieved 22 May Archived PDF from the original on 11 July Retrieved 1 October Multiples of America.
Archived from the original on 2 May Retrieved 30 April Acta Geneticae Medicae et Gemellologiae. The acute abdomen and intestinal obstruction". In Parks, Rowan W. Principles and practice of surgery 5th ed. Edinburgh: Churchill Livingstone. ISBN East African Medical Journal. Anatomy Research International. Medicinski Arhiv in Bosnian. Case report". Cirugia y Cirujanos.
Robbins' pathologic basis of disease 4th ed. Philadelphia: Saunders. NBC News. Archived from the original on 4 February Retrieved 24 August