Vermiform Appendix
Arteries of cecum and vermiform appendix. (Appendix visible at lower right, labeled as "vermiform process").
Normal location of the appendix relative to other organs of the digestive system (frontal view).
Latin	appendix vermiformis
Gray's	subject #249 1178
System	Digestive
Artery	appendicular artery
Vein	appendicular vein
Precursor	Midgut
MeSH	Appendix
Dorlands/Elsevier	a_54/12147735

In human anatomy, the appendix (or vermiform appendix; also cecal (or caecal) appendix; also vermix) is a blind ended tube connected to the cecum (or caecum), from which it develops embryologically. Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. Gray's Anatomy the Respiratory apparatus ( Apparatus Respiratorius Respiratory system Respiratory apparatus In Biology, a system is a group of organs that work together to perform a certain task Arteries are Blood vessels that carry blood away from the Heart. The appendicular artery, also appendiceal artery, descends behind the termination of the Ileum and enters the Mesenteriole of the Vermiform process In the Circulatory system, a vein is a Blood vessel that carries Blood back toward the Heart (as opposed to Artery, a blood vessel The appendicular vein is the vein which drains blood from the Vermiform appendix. Embryology (from Greek grc ἔμβρυον embryon, "unborn embryo" and grc -λογία -logia) is the study of the development The midgut is the portion of the Embryo from which most of the Intestines are derived Medical Subject Headings ( MeSH) is a huge Controlled vocabulary (or metadata system for the purpose of indexing journal articles and books Elsevier, the world's largest Publisher of Medical and Scientific literature, forms part of the Reed Elsevier group Human anatomy, which with physiology and biochemistry is a complementary basic medical science is primarily the scientific study of the morphology of the adult Human body The cecum or caecum (from the Latin caecus meaning Blind) is a pouch connected to the Ascending colon of the Large An embryo (from Greek:, plural, lit "that which grows" from en- "in" + bryein "to swell be full" is a multicellular The cecum is a pouch-like structure of the colon. The colon is a storage tube for solid wastes The main function of the colon appears to be extraction of Water and salts from Feces. The appendix is near the junction of the small intestine and the large intestine. In Biology the small Intestine is the part of the Gastrointestinal tract (gut between the Stomach and the Large intestine, and comprises The large intestine is the last part of the Digestive system: the final stage of the Alimentary canal in Vertebrate Animals Its function is to

The term "vermiform" comes from Latin and means "worm-like in appearance". Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome.

Size and location

The appendix averages 10 cm in length, but can range from 2 to 20 cm. The diameter of the appendix is usually between 7 and 8 mm. The longest appendix ever removed measured 26 cm in Zagreb, Croatia. ^[1]

The appendix is located in the lower right quadrant of the abdomen, or more specifically, the right iliac fossa. In Vertebrates such as Mammals the abdomen (belly constitutes the part of the body between the Thorax (chest and Pelvis. The iliac fossa is a large smooth concave surface on the internal surface of the ilium (part of the Hip bone) ^[2] Its position within the abdomen corresponds to a point on the surface known as McBurney's point (see below). McBurney's point is the name given to the point over the right side of the human Abdomen that is one-third of the distance from the ASIS ( Anterior superior iliac spine While the base of the appendix is at a fairly constant location, 2 cm below the ileocaecal valve ^[2], the location of the tip of the appendix can vary from being retrocaecal (74% ^[2]) to being in the pelvis to being extraperitoneal. The ileocecal valve is a Sphincter muscle situated at the junction of the Small intestine (ileum and the Large intestine. The pelvis (pl pelvises or pelves) or pelvic girdle is the irregular bony structure located at the base of the spine (properly known In higher Vertebrates the peritoneum is the Serous membrane that forms the lining of the abdominal cavity &mdash it covers most of the intra-abdominal In rare individuals with situs inversus, the appendix may be located in the lower left side. Situs inversus (also called situs transversus) is a congenital condition in which the major Visceral organs are reversed or mirrored

Function

Given the appendix's propensity to cause death via infection, and the seemingly perfect health of those who have had their appendix removed, the biological purpose of the appendix has mystified scientists for some time. An infection is the detrimental Colonization of a host Organism by a foreign Species. There have been cases of people who have been found, usually on laparoscopy or laparotomy, to have a congenital absence of an appendix. Laparoscopic surgery, also called Minimally invasive surgery (MIS, bandaid surgery, Keyhole surgery, or pinhole surgery A laparotomy is a surgical procedure involving an incision through the Abdominal wall to gain access into the Abdominal cavity. A congenital disorder is a disease or disorder that is present at birth There have been no reports of impaired immune or gastrointestinal function in these people. Immunity is a material term that describes a state of having sufficient biological defenses to avoid Infection, Disease, or other unwanted biological invasion

Vestigiality

The most common explanation is that the appendix is a vestigial structure with no absolute purpose. Vestigiality describes homologous characters of Organisms which have lost all or most of their original function in a species through In The Story of Evolution, Joseph McCabe argued thus:

The vermiform appendage—in which some recent medical writers have vainly endeavoured to find a utility—is the shrunken remainder of a large and normal intestine of a remote ancestor. Joseph Martin McCabe ( November 12 1867 – January 10 1955) was an English Writer and speaker on Freethought This interpretation of it would stand even if it were found to have a certain use in the human body. Vestigial organs are sometimes pressed into a secondary use when their original function has been lost.

One potential ancestral purpose put forth by Darwin^[3] was that the appendix was used for digesting leaves as primates. Charles Robert Darwin (February 12 1809 &ndash April 19 1882 was an English naturalist, who realised and demonstrated that all Species of life A primate is a member of the biological order Primates ( Latin: "prime first rank" the group that contains Lemurs the Aye-aye Over time, we have eaten fewer vegetables and have evolved, over millions of years, for this organ to be smaller to make room for our stomach. The term " vegetable " generally means the edible parts of Plants The definition of the word is traditional rather than Scientific, however In Human anatomy, the stomach is a J-shaped hollow muscular organ of the Gastrointestinal tract involved in the second phase of Digestion, following It may be a vestigial organ of ancient man that has degraded down to nearly nothing over the course of evolution. Evidence can be seen in herbivorous animals such as the Koala. The cecum of the koala is attached to the juncture of the small and large intestines and is very long, enabling it to host bacteria specific for cellulose breakdown. Early man’s ancestor must have also relied upon this system and lived on a diet rich in foliage. As man began to eat more easily digested foods, they became less reliant on cellulose-rich plants for energy. The cecum became less necessary for digestion and mutations that previously had been deleterious were no longer selected against. These alleles became more frequent and the cecum continued to shrink. After thousands of years, the once-necessary cecum has degraded to what we see today; the appendix. Darwin:^[4]

Few mammals other than humans, the other anthropoid apes, and other primates have an appendix. Charles Robert Darwin (February 12 1809 &ndash April 19 1882 was an English naturalist, who realised and demonstrated that all Species of life Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands Recent evidence based on a possible immune function is seen by one group of researchers to contradict the explanation of the appendix as a vestige of evolutionary development. eVolution is the third Album by eLDee, it was due to be released in 2008 ^[5]

The appendix is more developed in Old World monkeys. The Old World monkeys or Cercopithecidae are a group of Primates falling in the Superfamily Cercopithecoidea in the Clade ^[6]

However, such a view is actually a misinterpretation of the claim of vestigial status in evolutionary theory (i. e. , vestigial systems can have other functions).

Evolutionary theorists have suggested that natural selection selects for larger appendices because smaller and thinner appendices would be more susceptible to inflammation and disease^[7].

Immune Use

Loren G. Martin, a professor of physiology at Oklahoma State University, argues that the appendix has a function in fetuses and adults. Physiology (from Greek grc φύσις physis, "nature origin" and grc -λογία -logia) is the study of the mechanical physical A fetus (or foetus or fœtus) is a developing Mammal or other Viviparous Vertebrate, after the Embryonic stage and ^[8] Endocrine cells have been found in the appendix of 11 week old fetuses that contribute to "biological control (homeostatic) mechanisms. The endocrine system is an integrated system of small organs that involve the release of extracellular signaling molecules known as Hormones The endocrine system is instrumental Homeostasis (from Greek: ὅμος hómos, "equal" and ιστημι istēmi, "to stand" lit " In adults, Martin argues that the appendix acts as a lymphatic organ. The lymphatic system in Vertebrates is a network of conduits that carry a clear fluid called Lymph. The appendix is experimentally verified as being rich in infection-fighting lymphoid cells, suggesting that it might play a role in the immune system. The lymphatic system in Vertebrates is a network of conduits that carry a clear fluid called Lymph. An immune system is a collection of mechanisms within an Organism that protects against Disease by identifying and killing Pathogens and Tumor Zahid^[9] suggests that it plays a role in both manufacturing hormones in fetal development as well as functioning to 'train' the immune system, exposing the body to antigens in order that it can produce antibodies. Hormones (from Greek ὁρμή - "impetus" are chemicals released by cells that affect cells in other parts of the body Prenatal development is the process in which an embryo or fetus (or foetus) gestates during Pregnancy, from fertilization An antigen (from antibody-generating) or immunogen is a substance that prompts the generation of Antibodies and can cause an immune response Antibodies (also known as immunoglobulins, abbreviated Ig) are Gamma globulin Proteins that are found in Blood or other Bodily He notes that doctors in the last decade have stopped removing the appendix during other surgical procedures as a routine precaution, because it can be successfully transplanted into the urinary tract to rebuild a sphincter muscle and reconstruct a functional bladder. The urinary system (also called Excretory system or the genitourinary system (GUS is the Organ system that produces stores and eliminates Urine. A sphincter is a structure usually a circular Muscle, that normally maintains constriction of a natural body passage or orifice and which relaxes as required by normal physiological In Anatomy, the urinary bladder is a hollow muscular, and distensible (or elastic organ that sits on the Pelvic floor in Mammals It is the

Apparent function of the human vermiform appendix in the recovery from diarrhea. Although more than 2 million children die each year in developing countries as a result of diarrhea, children living in those countries face an estimated 1. 4 billion cases of diarrhea each year ^[10] Thus, the process of recovery from diarrhea is relatively effective in developing countries. This process is expected to be less critical in developed countries, where widespread epidemics resulting in diarrhea are uncommon and thus the loss of beneficial bacteria from the population as a whole is highly unlikely.

Latest Interpretation: Maintaining gut flora

Although it was long accepted that the immune tissue, called gut associated lymphoid tissue, surrounding the appendix and elsewhere in the gut carries out a number of important functions, explanations were lacking for the distinctive shape of the appendix and its apparent lack of importance as judged by an absence of side-effects following appendectomy. Components Lymphoid tissue in the gut is comprised of the following: Tonsils (Waldeyer's ring Adenoids (Pharyngeal tonsils ^[11] William Parker, Randy Bollinger, and colleagues at Duke University proposed that the appendix serves as a safe haven for useful bacteria when illness flushes those bacteria from the rest of the intestines. Duke University is a private Research University located in Durham, North Carolina, United States. The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have ^{[12] [5]} This proposal is based on a new understanding of how the immune system supports the growth of beneficial intestinal bacteria ^{[13] [14]}, in combination with many well-known features of the appendix, including its architecture and its association with copious amounts of immune tissue. The gut flora are the Microorganisms that normally live in the Digestive tract and can perform a number of useful functions for their hosts Such a function is expected to be useful in a culture lacking modern sanitation and healthcare practice, where diarrhea may be prevalent. In Medicine, diarrhea, also spelled diarrhoea (see spelling differences) is frequent loose or liquid Bowel movements Acute diarrhea ^[5] Current epidemiological data ^[15] show that diarrhea is one of the leading causes of death in developing countries, indicating that a role of the appendix as an aid in recovering beneficial bacteria following diarrhea may be extremely important in the absence of modern health and sanitation practices. Epidemiology is the study of factors affecting the Health and Illness of populations and serves as the foundation and Logic of interventions made in the Developing countries are countries that haven't reached Western-style standards of democratic government free market economy industrialization social programs and human rights guaranties ^[5]

Diseases

The most common diseases of the appendix (in humans) are appendicitis and carcinoid tumors. A disease is an abnormal condition of an organism that impairs bodily functions and can be deadly Appendicitis (or epityphlitis) is a condition characterized by Inflammation of the appendix. Carcinoid (also carcinoid tumour or carcinoid tumor) is a slow-growing but Malignant type of Neuroendocrine tumour, originating in the cells Appendix cancer accounts for about 1 in 200 of all gastrointestinal malignancies. Appendix cancer or appendiceal Cancer is a malignancy of the Vermiform appendix, accounting for about 1 in 200 of all gastrointestinal malignancies Adenomas also (rarely) present. An adenoma is a collection of growths (-oma of glandular origin

Appendicitis (or epityphlitis) is a condition characterized by inflammation of the appendix. Appendicitis (or epityphlitis) is a condition characterized by Inflammation of the appendix. Inflammation ( Latin, inflamatio, to set on fire is the complex biological response of vascular tissues to harmful stimuli such as Pathogens Virtually all cases of appendicitis require removal of the inflamed appendix, either by laparotomy or laparoscopy. A laparotomy is a surgical procedure involving an incision through the Abdominal wall to gain access into the Abdominal cavity. Laparoscopic surgery, also called Minimally invasive surgery (MIS, bandaid surgery, Keyhole surgery, or pinhole surgery Untreated, the appendix may rupture, leading to peritonitis, then shock, and, if continued untreated, death. Peritonitis is defined as Inflammation of the Peritoneum (the Serous membrane which lines part of the abdominal cavity and some of the Viscera Pain often begins in the center of the abdomen where the lining of the stomach is irritated then moves lower right as the condition develops; it is important to note that this makes diagnoses difficult in the early stages because an MRI or CT scan must be used to detect it. Computed tomography (CT is a Medical imaging method employing Tomography. Appendicitis presents as pain in the right lower quadrant with rebound tenderness (pain upon removal of pressure rather than application of pressure). Rebound tenderness is a clinical sign that a doctor may detect in physical examination of a patient's Abdomen. In particular, it presents at McBurney's point, 1/3 of the way along a line drawn from the Anterior Superior Iliac Spine to the Umbilicus. McBurney's point is the name given to the point over the right side of the human Abdomen that is one-third of the distance from the ASIS ( Anterior superior iliac spine The anterior superior iliac spine (ASIS is an important landmark of surface anatomy The navel (also called an umbilicus or colloquially belly button) is a Scar on the Abdomen, caused when the Umbilical cord is removed Typically, point (skin) pain is not present until the parietal peritoneum is inflamed as well. In higher Vertebrates the peritoneum is the Serous membrane that forms the lining of the abdominal cavity &mdash it covers most of the intra-abdominal Fever and immune system response are also characteristic of appendicitis.

The surgical removal of the vermiform appendix is called an appendicectomy (or appendectomy). An appendicectomy (or appendectomy) is the surgical removal of the Vermiform appendix. This procedure is normally performed as an emergency procedure, when the patient is suffering from acute appendicitis. In Medicine, an acute disease is a disease with either or both of a rapid onset a short course (as opposed to a chronic course In the absence of surgical facilities, intravenous antibiotics are used to delay or avoid the onset of sepsis; it is now recognized that many cases will resolve when treated non-operatively. Intravenous therapy or IV therapy is the giving of Liquid substances directly into a Vein. In modern usage an antibiotic is a Chemotherapeutic agent with activity against Microorganisms such as Bacteria, fungi or Protozoa Sepsis is a serious medical condition characterized by a whole-body inflammatory state (called a Systemic inflammatory response syndrome or SIRS caused In some cases the appendicitis resolves completely; more often, an inflammatory mass forms around the appendix. This is a relative contraindication to surgery.

Use as efferent urinary conduit

The appendix is used for the construction of an efferent urinary conduit, in an operation known as the Mitrofanoff procedure,^[16] in people with a neurogenic bladder. Mitrofanoff appendicovesicostomy, also known as the Mitrofanoff procedure, is a Surgical procedure in which the appendix is used to create a conduit between Neurogenic bladder refers to dysfunction of the Urinary bladder due to disease of the Central nervous system or peripheral nerves involved in the control of Micturition

Additional image

Mucinous adenocarcinoma of the appendix tip

See also

• Homology (biology)
• McBurney's point

References

External links

• "The vestigiality of the human vermiform appendix: A Modern Reappraisal" -- evolutionary biology argument that the appendix is vestigial
• Purpose of appendix believed found CNN article
• Appendix May Actually Have a Purpose WebMD article

• SUNY Labs 37:12-0102 - "Abdominal Cavity: The Cecum and the Vermiform Appendix"