Appendix
The site of your pain may vary, depending on your age and the position of your appendix. When you're pregnant, the pain may seem to come from your upper abdomen because your appendix is higher during pregnancy.
appendix
A blockage in the lining of the appendix that results in infection is the likely cause of appendicitis. The bacteria multiply rapidly, causing the appendix to become inflamed, swollen and filled with pus. If not treated promptly, the appendix can rupture.
A pocket of pus that forms in the abdomen. If your appendix bursts, you may develop a pocket of infection (abscess). In most cases, a surgeon drains the abscess by placing a tube through your abdominal wall into the abscess. The tube is left in place for about two weeks, and you're given antibiotics to clear the infection.
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 large intestine, located at the junction of the small and the large intestines. The term "vermiform" comes from Latin and means "worm-shaped". The appendix was once considered a vestigial organ, but this view has changed since the early 2000s.[1][2] Research suggests that the appendix may serve an important purpose as a reservoir for beneficial gut bacteria.
The human appendix averages 9 cm (3.5 in) in length, ranging from 5 to 35 cm (2.0 to 13.8 in). The diameter of the appendix is 6 mm (0.24 in), and more than 6 mm (0.24 in) is considered a thickened or inflamed appendix. The longest appendix ever removed was 26 cm (10 in) long.[3] The appendix is usually located in the lower right quadrant of the abdomen, near the right hip bone. The base of the appendix is located 2 cm (0.79 in) beneath the ileocecal valve that separates the large intestine from the small intestine. Its position within the abdomen corresponds to a point on the surface known as McBurney's point.
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.[19] In addition, there are different immune cells called innate lymphoid cells that function in the gut in order to help the appendix maintain digestive health.[20] Research also shows a positive correlation between the existence of the appendix and the concentration of cecal lymphoid tissue, which supports the suggestion that not only does the appendix evolve as a complex with the cecum but also has major immune benefits.[21]
Common diseases of the appendix (in humans) are appendicitis and carcinoid tumors (appendiceal carcinoid).[22] Appendix cancer accounts for about 1 in 200 of all gastrointestinal malignancies. In rare cases, adenomas are also present.[23]
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.[24]
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.[24]
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 as a means to access the colon in children with paralysed bowels or major rectal sphincter problems. The appendix is brought out to the skin surface and the child/parent can then attach a catheter and easily wash out the colon (via normal defaecation) using an appropriate solution.[27]
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.[28]
Recently ... improved understanding of gut immunity has merged with current thinking in biological and medical science, pointing to an apparent function of the mammalian cecal appendix as a safe-house for symbiotic gut microbes, preserving the flora during times of gastrointestinal infection in societies without modern medicine. 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.[29]
In a 2013 paper, the appendix was found to have indepedently evolved in different animals at least 32 times (and perhaps as many as 38 times) and to have been lost no more than six times over the course of history. [30] A more recent study using similar methods on an updated database yielded similar, though less spectacular results, with at least 29 gains and at the most 12 losses (all of which were ambiguous), and this is still significantly asymmetrical.[31] This suggests that the cecal appendix has a selective advantage in many situations and argues strongly against its vestigial nature. 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.[32]
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 found that lymphatic tissue encourages the growth of some beneficial gut bacteria, which play an important role in human digestion and immunity.
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. (8) The appendix, it seems, may have independently evolved in different animals at least 32 times over the course of history, suggesting the organ does have an important function. (4)
Appendicitis is often the result of an abdominal infection that has spread to the tiny organ, or some kind of obstruction that has blocked the small opening of the appendix. Sources of blockage include, among other things:
Appendix K is a standalone appendix that may be utilized by states during emergency situations to request amendment to approved 1915(c) waivers. It includes actions that states can take under the existing Section 1915(c) home and community-based waiver authority in order to respond to an emergency. Other activities may require the use of various other authorities such as the Section 1115 demonstrations or the Section 1135 authorities. This appendix may be completed retroactively as needed by the state.
Appendix: Satisfying the O-1A Evidentiary Requirements [2 USCIS-PM M.4, Appendices Tab] describes examples of evidence that may, in some circumstances, satisfy the O-1A evidentiary requirements, as well as considerations that are relevant to evaluating such evidence. While many of the listed examples and considerations are especially relevant to beneficiaries in fields related to science, technology, engineering, or mathematics (STEM),[21] the guidance in the appendix may be relevant to any O-1A petition, as the evidentiary requirements are the same for all persons in the sciences, education, business, and athletics.
Restriction of Appendix materials is intended to rectify inequities in the peer review process that can arise from submission of inappropriate or excessive appendix materials by some applicants and consideration of Appendix materials in peer review by some, but not all, reviewers. 041b061a72