In what ways is the narrator in Cat's Cradle (John) is similar to yet different from the narrator in The Great Gatsby (Nick)? Do they succeed in...

Narrators hold different positions in the stories they tell. First person narrators tell the story from an interactive position. He/she is one of the characters, and readers generally cannot know anything the narrator doesn't know. Both Fitzgerald's narrator Nick in The Great Gatsby and Vonnegut's narrator in Cat's Cradle are first person narrators, and while they share some similarities, they are also very different.

Vonnegut's narrator John is a first-person central narrator, meaning that he is not just the narrator, he is also the main character. Everything John sees, readers see. Everywhere John goes, readers go. Everything John thinks, readers can 'hear.' Readers also receive all the story's details from John. There are no other characters who really contribute to our understanding of the story. Even when we 'hear' other characters speaking or reacting, it is really John relating what he hears and what he thinks other characters think.

Fitzgerald's narrator Nick is, similarly, a first-person narrator, but he is really more of a peripheral narrator. Rather than being the main character, Nick is only one character of many, but in his position as a peripheral narrator, Nick’s job is to hear and convey to the reader everyone else's stories.

One question that a reader must ask of a narrator is whether or not he/she is reliable or unreliable. A reliable narrator is one who is consistent in his/her story and in the world he/she creates for the reader. He/she tells the truth and (usually) nothing but. An unreliable narrator is one whose story cannot be taken at face value. He/she has little or no credibility. This can be for a number of reasons, including insanity, lying, or just a total lack of moral character. Both John and Nick are similar yet again in that they are unreliable narrators, but they differ in the reason why. 

John is an unreliable narrator because he is a liar. Some would argue that John is a reliable narrator because although he lies, he is honest about the fact that he is lying. We can see this immediately in the novel's epigraph:

"Nothing in this book is true.
Live by the foma that make you brave and kind and healthy and happy.
The Book of Bokonon 1:5" (Vonnegut, 1963, p.1)

However, honesty about lying still does not reveal truth to the reader, so even here in the epigraph, where 'foma' translates as 'lies,' we see that John is unreliable. We can see other evidence in the text as well. In Chapter 3, John writes, "In the autobiographical section of The Books of Bokanon he writes a parable on the folly of pretending to discover, to understand" (p. 6), which seems to suggest that the search for truth displays a lack of good sense and that perhaps truth is relative. In Chapter 15, John shares Dr. Breed's opinion that "everybody does about the same amount of thinking. Scientists simply think about things in one way, and other people think about things in others" (p. 22). Again, this suggests that truth is relative. Although everyone thinks, they all think in different ways and emphasize different things. In another example, John is discussing Dr. Hoenikker's death with Miss Faust:

"Dr. Breed keeps telling me the main thing with Dr. Hoenikker was truth."

"You don't seem to agree."

"I don't know whether I agree or not. I just have trouble understanding how truth, all by itself, could be enough for a person." (pp. 33-34)

Here, John clearly indicates that he believes truth is not enough to make living and the knowledge of impending death bearable. He seems to believe that there needs to be something other than truth to ameliorate the burdens of living life. His own lies paired with his consistent questioning of an objective Truth makes John a classic unreliable narrator.

Nick is also an unreliable narrator, but it's not necessarily because he's a liar. Rather, it's because he sees himself as morally superior to those whose stories he tells. The novel begins with this revelation:

‘Whenever you feel like criticizing any one,’ [my father] told me, ‘just remember that all the people in this world haven’t had the advantages that you’ve had.’ He didn’t say any more but we’ve always been unusually communicative in a reserved way, and I understood that he meant a great deal more than that. In consequence I’m inclined to reserve all judgment. (Fitzgerald, 1925. p. 3)

Any time a narrator proclaims himself to be morally superior in any way, the reader should pay particular and close attention to how that narrator functions in the story. And in this story, Nick, despite his assertion to the contrary, does a lot of judging. He begins by telling us that Gatsby "represented everything for which [he has] an unaffected scorn" (p. 4). In his outing with Tom and Daisy, Nick sees Myrtle, whom he describes as having a "simple mind" (p. 133), but he doesn't have anything particularly nice to say about Tom and Daisy, either: 

They were careless people, Tom and Daisy—they smashed up things and creatures and then retreated back into their money or their vast carelessness or whatever it was that kept them together, and let other people clean up the mess they had made…. (p. 191).

But Nick's reliability as a narrator doesn't just hinge on the lack of continuity between his perception of himself as a non-judgmental person and the reality that he is. He also undermines his credibility by engaging in many of the same activities and behaviors for which he judges everyone else. For example, although Nick has a girlfriend back home, he flirts with Jordan and has a casual fling with a girl in the city. He comments on the drunken guests at Myrtle's party, but he gets just as drunk as the rest of them. And at the end, Jordan calls him out:

'You said a bad driver was only safe until she met another bad driver? Well, I met another bad driver, didn't I? I mean it was careless of me to make such a wrong guess. I thought you were rather an honest, straightforward person. I thought it was your secret pride' (pp. 189-190).

Nick responds, “I’m thirty. [. . .] I’m five years too old to lie to myself and call it honor” (p. 190). There are some who argue that this change of heart, and Nick's compassionate attention to Gatsby's funeral and ultimate return to the Midwest, allow him to be a reliable narrator, but at this point, the damage is done. First, we have no real idea, because he probably doesn't either, about what Nick is lying. Second, our perspectives and perceptions of the other characters have been well- and permanently shaped. No, Nick is not a reliable narrator.

As to whether or not our narrators' goals have been reached by the end of these novels, it's hard to say. Fitzgerald's Nick wants to leave the monotony of Midwestern life to make his fortune, and he attaches himself to people who live exciting, glamorous lives in the rich fast lane. But in the end (or perhaps from the start), he has little tolerance for the shallow and self-serving people he finds, and he returns to the Midwest, perhaps changed somewhat in character but not in circumstance. Vonnegut's John has perhaps convinced his readers to explore multiple philosophical truths rather than an objective Truth, but only the reader(s) can say whether or not either was successful.

What are bacterial infections? |

Causes and Symptoms

Bacteria are very small, one-celled organisms (the cell being the smallest unit of a living organism) with an average size of thousandths of a millimeter. Based on their relatively simple structure, they are classified as prokaryotic cells. Prokaryotic cells have a rigid outer cell wall, very simply organized hereditary material (deoxyribonucleic acid, or DNA) floating free within the cell, and only a few other structures necessary for their survival, growth, and reproduction. Eukaryotic cells, such as those found in humans, plants, and other animals, have highly organized DNA and many more internal structures. Despite the fact that bacteria are relatively “simple,” they are still very complex living organisms.

The many types of bacteria can be divided into three categories based on their shape: coccus (round), bacillus (rod-shaped), or spirillum (spiral). Another major distinction between types of bacteria is based on the sugar and lipid (fat) composition of their cell walls. This difference can be identified through Gram staining, the result of the stain determining whether the organism is gram-positive or gram-negative. Various types of bacteria may have additional structures that are useful in their identification. Capsules and slime layers are water-rich sugary materials secreted by the bacteria that cling to their surfaces and form halolike structures. Flagella are long, thin, whiplike structures found in one location on the bacterium or occasionally covering its entire surface. These structures are used to enhance the motility, or movement, of the bacteria.

Some bacteria are normal, harmless inhabitants of human bodies, such as those on the surface of the skin. Others, such as those that live in the human intestinal tract, aid in digestion and are essential for good health. The warm, moist, nutrient-rich human body also provides an excellent breeding ground for numerous harmful bacterial invaders. For bacteria to cause infectious disease, several stages must occur. The bacteria must enter the person, they must survive and multiply on or in the person, they must resist the natural defenses of the human body, and they must damage the infected person. Most bacterial diseases are infectious because of the ease with which they can be transmitted from individual to individual by physical contact with the person, a contaminated object, or bacteria expelled into the air, such as by coughing or sneezing. A few bacterial diseases, such as food poisoning, are not classified as infectious.

Bacterial infections cause disease by a variety of mechanisms. Many of them produce chemical compounds that are toxic to human beings. For example, Salmonella
and Staphylococcus aureus are two types of bacteria that are capable of causing food poisoning. Clostridium botulinum produces the deadly
botulism toxin. In each case, ingestion of the toxin in contaminated food can lead to serious illness. Clostridium tetanii can enter the body through puncture wounds and will multiply rapidly deep in tissue where there is little exposure to the air. The toxin that it produces acts on the central nervous system and causes severe muscle spasms, which can lead to death from respiratory failure. Water that has been contaminated with raw sewage is a potent source of disease-causing bacteria. Vibrio
cholera

produces a potent toxin that causes severe diarrhea leading to death if it is not vigorously treated. Certain varieties of Escherichia coli and Shigella found in contaminated water can also cause severe intestinal disorders. Toxic shock syndrome is associated with the production of toxins by Staphylococcus aureus.

Another common cause of disease from bacterial infections is the result of the physical destruction of tissue by the invading organisms.
Leprosy (also called Hansen’s disease), caused by Mycobacterium leprae, if left untreated, can lead to severe deterioration and disfiguration of large areas of a person’s body. If a wound interrupts the blood supply to an area of the body such as a hand or foot, the tissues begin to decay, thereby providing nutrients for many bacteria, especially Clostridium perfringens. These bacteria can greatly accelerate the destruction of the tissue, which causes the condition known as gas
gangrene.

In many cases, disease results when the infecting bacteria are recognized by the body’s natural defense system (the
immune system) as “nonself,” that is, as invaders. Certain cells within the body are designed to attack intruders and eliminate them. During this process, disease symptoms that are consequences of the immune system’s response may be evident: inflammation (redness and swelling), the production of pus, and fever, among other symptoms. In some cases, certain components of the bacteria, such as capsules and slime layers, may protect them from being eliminated by the immune system. The bacteria may also multiply exceedingly rapidly, producing increasing amounts of toxins that overwhelm the capacity of the immune system to eliminate them. In these cases, continued and increasingly elevated disease symptoms such as fever can cause severe, even fatal, damage unless an alternate method for eliminating the infection is found. Failure to eliminate the bacterial invaders can also lead to a long-term, chronic infection that damages body tissues.

Many
respiratory diseases are associated with the body’s immune response to bacterial invasion. Streptococcus pyogenes is the causative agent of
strep throat, whose features include severe redness, inflammation, pain, and the production of pus in throat tissue. In a small percentage of cases, strep throat can also lead to an infection of and potential permanent damage to the heart
valves in a disease called rheumatic fever. In tuberculosis, Mycobacterium tuberculosis
enters the lungs through inhalation. The body’s defense system walls off the intruders and forms a nodule called a tubercle deep in the lung tissue. Nevertheless, the bacteria continue to multiply in the nodule and can travel to new sites in the lung. Tubercle formation occurs at these new sites. Eventually, this
repeated cycle of infection and nodule formation becomes a chronic disease and leads to the destruction of lung tissue. Bacterial
pneumonia can be caused by several different organisms, including Klebsiella pneumoniae and Mycobacterium pneumoniae. A pneumonia-like disease, Legionnaires’ disease, was first identified in 1976 after twenty-nine delegates to an American Legion convention died from a mysterious respiratory disorder. The lengthy process of identifying a causative agent led to the discovery of a type of bacteria not previously known, Legionella pneumophila.

The human urinary and genital tracts are also potential havens for invading bacteria. Cystitis (bladder infections) are caused by many different types of bacteria. Kidney infections can be acquired as corollaries of urinary tract infections. Sexually transmitted diseases (STDs)
are contracted through sexual contact with an infected partner, and two common STDs have a bacterial origin.
Gonorrhea is caused by Neisseria gonorrhoeae and leads to a severe inflammatory response and rapid spread of the organisms throughout the body. If not treated, it can lead to sterility as well as to diseases of the joints, heart, nerve coverings, eyes, and throat. Syphilis, caused by Treponema pallidum, can also have serious consequences if left untreated, including dementia and death. In addition, it can be passed to a fetus developing inside an infected mother in a condition known as congenital syphilis.

Treatment and Therapy

The medical management of the many bacterial infections and the diseases they cause begins with diagnosis. Diagnosis relies on a variety of biochemical tests that are analyzed in conjunction with the signs and symptoms exhibited by the infected individual. Treatment is then designed so that it not only eliminates the disease symptoms but also eradicates all invading bacterial organisms, thereby minimizing the chance of a recurrence of the disease. Prevention involves steps that the individual takes to avoid potential contact with infectious diseases, as well as the use of medical procedures that protect against specific bacterial diseases.

To treat a bacterial disease properly, the invading organism must be identified correctly. In some cases, symptomology can be specific enough to identify the offending bacterium, but since there are literally thousands of different types of disease-causing organisms, a systematic approach using a variety of tests is undertaken to make a definitive diagnosis. First, a specimen from the infected person is collected. This may be a blood or urine sample; a swab of the infected area, such as the throat or another skin surface; or a secretion, such as sputum, mucus, or pus. Since human bodies are normally inhabited by a variety of harmless bacteria, the individual types of bacteria are isolated in pure cultures, in which each bacterium present is of the same type. The pure cultures are then tested to determine the identity of the organisms. Staining procedures, such as Gram staining, and microscopic examination of the stained bacteria to determine the Gram reaction and the shape of the bacteria can narrow down the identity of the organisms considerably.

Based on these results, a standard series of tests is performed, continually narrowing down the possible identities until only one remains. One test measures the organisms’ growth requirements. Many identifications are aided by analyzing the types of sugars and proteins that the organisms can use as food sources. The by-products of their metabolism (chemical reactions occurring inside the bacteria), such as acids and gas, are identified. Oxygen requirements, motility, and the presence of a capsule are three other common characteristics that are examined. For cases in which the identification of a particular variety of one type of bacteria is necessary, more complex tests may be undertaken, such as an analysis of the particular sugars and proteins on the surface of the organism or tests for the production of specific toxins. Once the bacterium’s identity is confirmed, treatment may begin.

The most common type of treatment for bacterial infection is antibiotic therapy.
Antibiotics are chemical compounds that kill bacteria. Originally discovered as antibacterial compounds produced by bacteria, molds, and fungi (such as penicillin from bread mold), many more are synthetically produced. Antibiotics work in a variety of fashions. Some, such as penicillin and the cephalosporins, interfere with the synthesis of cell walls by bacteria, thus preventing the organisms from multiplying. Other commonly used antibiotics prevent the bacteria from synthesizing the proteins that they need to survive and multiply. These include the tetracyclines (a class of antibiotics that act against a large range of bacteria), erythromycin, and streptomycin. A host of other antibiotics target a variety of bacterial functions, including specific chemical reactions and the propagation of genetic material, and the structural components of the bacteria. Each class of antibiotics works best on certain types of bacteria. For example, penicillin is most efficient in killing cocci (such as Streptococcus and Staphylococcus) and
Gram-positive bacilli.

Frequently, the symptoms of a bacterial disease may disappear rapidly after the beginning of antibiotic therapy. This reaction is attributable to the inhibition of bacterial multiplication and the destruction of most of the microorganisms. A small number of the bacteria may not be killed during this initial exposure to antibiotics, however, and if antibiotic therapy is ended before all are killed, a recurrence of the disease is likely. A full prescription of antibiotics should be taken to avoid this situation. For example, effective treatment and eradication of all bacteria in tuberculosis may take six months to a year or more of antibiotic treatment, despite the fact that the symptoms are alleviated in a few weeks.

Upon repeated exposure to a type of antibiotic, some bacteria develop the capacity to degrade or inactivate the antibiotic, thus rendering that drug ineffective against the resistant microorganism. In these cases, other antibiotics and newly developed ones are tested for their effectiveness against the bacteria. Such situations have arisen in the bacteria that cause gonorrhea and tuberculosis.

While antibiotics exist to combat infections of most types of bacteria, in some cases the human immune system is capable of clearing the infection without additional intervention. In these instances, the symptoms of the infection are treated until the body heals itself. This is the common treatment path in mild cases of food poisoning, such as those caused by some Salmonella and Staphylococcus varieties. Diarrhea and vomiting are treated by replacing water and salts, by drinking large volumes of fluids, and perhaps by using over-the-counter remedies to ease some of the symptoms.

Many bacterial diseases can be easily prevented through good hygiene. Foods, such as eggs and meats, that are not thoroughly cooked may become quickly contaminated by the rapid growth of food-poisoning organisms present on their surfaces. Proper cooking kills these organisms. Similarly, foods that are not properly stored but left out in warm places can also provide a potent breeding ground for toxin-producing bacteria. Picnic food not properly refrigerated is a common source of food poisoning. Similarly, questionable water sources should never be used for drinking or cooking water without proper treatment. Filtering with an ultrafine filter specifically designed to remove bacteria is one safeguard, as is boiling for the required time period based on altitude. Food that may have been washed with contaminated water sources should always be cooked or peeled before consumption.

Many diseases can be prevented with vaccinations. A bacterial vaccine is a mixture of a particular bacterium, its parts, or its inactivated toxins. When this solution is injected into an individual, it provides immunity (resistance to infection) to the particular organism contained in the vaccine. Some vaccines provide lifetime immunity when enhanced with an occasional booster shot, while some are relatively short-acting. Many types of vaccines that are directed against specific diseases are part of standard preventive care given to children. For example, the DTaP vaccine (or Tdap for adults) confers immunity to diphtheria, pertussis (whooping cough), and tetanus. Some vaccines are useful for individuals who are living, working, or traveling in areas where certain diseases are endemic, or for those who regularly come into contact with infected individuals. Examples of these sorts of vaccines include those for plague (Yersinia pestis), typhoid fever (Salmonella typhi), cholera, and tuberculosis.

Perspective and Prospects

Bacteria were first described as “animalcules” by the Dutch scientist Antoni van Leeuwenhoek
in 1673 after he observed them in water-based mixtures with a crudely designed microscope. In 1860,
Louis Pasteur recognized that bacteria could cause the spoiling of wine and beer because of the by-products of their metabolism. Pasteur’s solution to this problem was heating the beverages enough to kill the bacteria, but not change the taste of the drink—a process known as pasteurization, which is used today on milk and alcoholic beverages. In addition, Pasteur settled a long-standing debate on the origin of living things that seemed to arise spontaneously in fluids exposed to the air. He demonstrated that these life-forms were seeded by contaminating bacteria and other microorganisms found in the air, in fluids, and on solid surfaces. Pasteur’s work led to standard practices in laboratories and food processing plants to prevent unwanted bacterial contamination; these practices are referred to as aseptic techniques.

Prior to the late nineteenth century, deaths from wounds and simple surgeries were quite common, but the reason for these high mortality rates was unknown. In the 1860s, Joseph Lister, an English surgeon, began soaking surgical dressings in solutions that killed bacteria, and the rate of survival in surgical and wound patients was greatly improved. In 1876, Robert Koch, a German physician, discovered rod-shaped bacteria in the blood of cattle that died from anthrax, a disease that was devastating the sheep and cattle population of Europe. When he injected healthy animals with these bacteria, they contracted anthrax, and samples of their blood showed large numbers of the same bacteria. By these and other experiments, Koch, Lister, and others proved the “germ theory of disease”—that microorganisms cause disease—and appropriate measures were instituted to protect against the transmission of bacteria to humans through medical procedures and food.

A milestone in the prevention of infectious diseases was the development of vaccinations. The first vaccine was developed in 1798, long before the germ theory of disease was proven. The British physician Edward Jenner first used vaccination as a preventive step against the contraction of deadly smallpox, a viral disease. How vaccinations work and their use as a protection against bacterial diseases were discovered around 1880 by Pasteur.

The first antibiotic, penicillin, was discovered by Alexander Fleming in 1928. Since then, scores of others, produced both naturally and synthetically, have been analyzed and used in the treatment of bacterial diseases. All these discoveries have made bacterial disease a much less deadly category of illness than it was in the late nineteenth century. Yet bacterial diseases are by no means conquered. Overuse of antibiotics in medical practice and in cattle feed results in the appearance of new varieties of bacteria that are resistant to standard antibiotic therapy. Research will continue to develop new means of controlling and destroying such infective organisms. Bacteria also play an important role in synthesizing new antibiotics and other pharmaceuticals in the laboratory through recombinant DNA technology. These organisms will continue to provide challenges and opportunities for human health in the years to come.

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What is the gastrointestinal system?

Structure and Functions

The gastrointestinal system or alimentary canal exists as a tube that runs through the body from mouth to anus. The wall of the tube is composed of four layers of tissue. The outermost layer, the serosa, is part of a large tissue called the peritoneum, which covers internal organs and lines body cavities. Extensions of the peritoneum called mesenteries anchor the organs of digestion to the body wall. Fatty, apronlike structures that hang in front of the abdominal organs are also modifications of the peritoneum. They are called the lesser and the greater omentum. The muscular layer, composed of circular and longitudinal muscles, makes up the bulk of the wall of the tube. The contractions of this layer aid in moving materials through the tube. Nerves, blood vessels, and lymph vessels are found in the third layer, the submucosa. The innermost or mucous layer has glands for secretion and modifications for absorption.

The tube is compartmentalized, and each section is equipped to accomplish some part of the digestive process. The mechanical phase of digestion involves the physical reduction of food to a semiliquid state; this is accomplished by tearing, chewing, and churning the food. Chemical digestion utilizes enzymes to reduce food to simple molecules that can be absorbed and used by the body to provide energy and to build and repair tissue.

The mouth (also called the buccal or oral cavity) marks the beginning of the gastrointestinal system and the digestive process. The mouth is divided into two areas. The vestibule is the space between the lips, cheeks, gums, and teeth. Lips, or labia, are the fleshy folds that surround the opening to the mouth. The skin covers the outside, while the inside is lined with mucous membrane. The colored part of the lips, called the vermilion, is a juncture of these two tissues. Because the tissue at this point is unclouded, underlying blood vessels can be seen. A membrane called the labial frenulum attaches each lip to the gum, or gingivalum.

The oral cavity occupies the space posterior to the teeth and anterior to the fauces or opening to the throat. It is bounded on the sides by cheeks and on the roof by an anterior bony structure called the hard palate and a posterior muscular area, the soft palate. The uvula, a cone-shaped extension of the soft palate, can be seen hanging down in front of the fauces. The floor of the oral cavity is formed by the tongue and associated muscles. Taste buds are found on the surface of the tongue. The bottom of the tongue is anchored posteriorly to the hyoid bone. Anteriorly, the membranous frenulum lingua anchors the tongue to the floor of the mouth. The tongue’s movement is controlled by extrinsic muscles that form the floor of the mouth and by intrinsic muscles that are part of the tongue itself. The movements of the tongue assist in speaking, swallowing, and forming food into a bolus.

Teeth, found in gum sockets, are the principal means of mechanical digestion in the mouth. Human teeth appear in two sets. The deciduous or milk teeth are the first to appear. There are usually ten in each jaw, and they are replaced by the second, permanent set during childhood. The permanent set consists of sixteen teeth in each jaw. The four incisors and two canines have sharp chiseled edges, which permit biting and tearing of food. The four premolars and six molars have flat surfaces that are used in grinding the food. Frequently, the third pair of molars or wisdom teeth do not erupt until later in adolescence. The crown of a tooth appears above the gum line while the roots are embedded in the gum socket. The small area between the crown and the root is called the neck. The crown is covered with enamel and the root with cementum. Dentin is beneath the covering in both areas and forms the bulk of the tooth. The central cavity of the tooth is filled with a soft membrane called pulp. Blood vessels and nerves are
embedded in the pulp.

At the rear of the mouth, the fauces or opening leads to the pharynx. The pharynx is a common passageway for the movement of air from nasal cavity to trachea and food from mouth to esophagus. The esophagus is a tube approximately twenty-five centimeters long. Most of the esophagus is located within the thoracic cavity, although the lower end of the tube pierces the diaphragm and connects with the stomach in the abdominal cavity. Both ends of the esophagus are controlled by a circular muscle called a sphincter. The movement of food through the esophagus is assisted by gravity and the contractions of the muscularis layer. No digestion is accomplished in either the pharynx or the esophagus.

The stomach, a J-shaped organ, is divided into four areas: the cardia, fundus, body, and pyloris. The cardia lies just below the sphincter at the juncture of esophagus and stomach, while the fundus is a pouch that pushes upward and to the left of the cardia. The large central area is the body, and the lower end of the stomach is the pyloris. Here another sphincter, the pyloric valve, controls the opening between stomach and intestine. The mucosa of the stomach is arranged in folds called rugae. The rugae permit distension of the organ as it fills. Gastric and mucus glands are present in the mucosa. The gastric glands produce and secrete enzymes that are specific for protein digestion, as well as hydrochloric acid, which creates the proper acid environment for enzyme action. The muscularis of the stomach wall has three layers of muscle with a circular, longitudinal, and oblique arrangement. The muscle arrangement facilitates the churning action that reduces the food to a semiliquid called
chyme. The pyloric valve relaxes under neuronal and hormonal influence, and the chyme is moved into the small intestine.

The site for the completion of digestion and the absorption of digested material is the small intestine. This tube, with a 2.5-centimeter diameter and a length of 6.4 meters, is coiled into the mid and lower abdomen. The first twenty-five centimeters of the small intestine constitute the duodenum. This is followed by the jejunum, which is 2.5 meters long. The ileum, at 3.6 meters, terminates at the ileocecal valve, which connects the small to the large intestine. The interior of the small intestine is characterized by the presence of fingerlike projections of the mucosa called villi that contain blood and lymph capillaries and circular folds of submucosa (the plicae circularis), both of which provide absorption surface for the digested food. Mucosal glands produce enzymes that contribute to the digestion of carbohydrates, lipids, and proteins. Enzymes from the pancreas and bile from the liver enter the small intestine at the duodenum and aid the chemical digestion.

The final compartment in the gastrointestinal system is the large intestine, sometimes called the bowel or colon. This tube, with a diameter of 6.5 centimeters and a length of 1.5 meters, is divided into the cecum; the ascending, transverse, and descending colon; the rectum; and the anal canal. The cecum is a blind pouch located just below the ileocecal valve. The fingerlike appendix is attached to the cecum. The ascending colon extends from the cecum up the right side of the abdomen to the underside of the liver, where it turns and runs across the body. The colon descends along the left side of the abdomen. The last few centimeters of colon form an S-shaped curve that gives the section its name, sigmoid colon. Three bands of longitudinal muscle called taeniae coli run the length of the colon. Contraction of these bands causes pouches or haustra to form in the colon, giving the tube a puckered appearance. The sigmoid colon leads into the rectum, a twenty-centimeter segment that terminates in a short anal canal. The anus is the opening from the anal canal to the exterior of the body.

Disorders and Diseases

Because the primary function performed in the gastrointestinal system is the physical and chemical preparation of food for cellular absorption and use, any malfunction of the process has implications for the overall metabolism of the body. Structural changes or abnormalities in the anatomy of the system interfere with the proper mechanical and chemical preparation of the food.

Teeth are the principal agents of mechanical digestion or mastication in the mouth. Dental caries or tooth decay involves a demineralization of the enamel through bacterial action. Disrupted enamel provides an entrance for bacteria to underlying tissues, resulting in infection and inflammation of the tissues. The resulting pain and discomfort interfere with the biting, chewing, and grinding of food. Three pairs of salivary glands secrete the water-based, enzyme-containing fluid called saliva. These glands can be the target of the virus that causes mumps. (Although the pain and swelling that are typical of this disease can prevent swallowing, the more important effect of the virus in males is the possible inflammation of the testes and subsequent sterility.)

The gastroesophageal sphincter at the lower end of the esophagus controls the movement of materials from the stomach into the esophagus. Relaxation of this sphincter allows a backflow of food (gastroesophageal reflux

) to occur. The acidity of the stomach contents damages the esophageal lining, and a burning sensation is experienced. Substances such as citric fruits, chocolate, tomatoes, alcohol, and nicotine as well as body positions that increase abdominal pressure, such as bending or lying on the side, induce heartburn or indigestion. A hiatal hernia
occurs when a defect of the diaphragm allows the lower portion of the esophagus and the upper portion of the stomach to enter the chest cavity; it causes
heartburn and difficulty in swallowing.

Pathologies and abnormalities of the stomach and intestines are studied in the medical science called gastroenterology. The stomach is the site of both mechanical and chemical digestion. Although small amounts of digested food begin to pass into the small intestine within minutes following a meal, the chyme usually remains in the stomach for three to five hours. Relaxation of the gastroesophageal sphincter will result in reflux; and stimulation by nerves from the medulla of the brain can cause the forceful emptying of stomach contents through the mouth. This is called vomiting and may be brought about by irritation, overdistension, certain foods, or drugs. Excessive vomiting results in dehydration, which in turn upsets electrolyte and fluid balance.

Chemical digestion in the stomach requires an acidic environment. This is provided by gastric glands, which secrete hydrochloric acid. The tissue lining the stomach protects it from this acidity and prevents self-digestion. Oversecretion of the gastric juices or a breakdown of the stomach lining can cause lesions or peptic ulcers to form in the mucosal lining. Gastritis, the inflammation of the stomach mucosa brought on by the ingestion of irritants such as alcohol and aspirin or an overactive nervous stimulation of the gastric glands, may be the underlying cause of ulcer formation. Ulcers can form in the lower esophagus, stomach, and duodenum because these are the organs that come in contact with gastric juice. The terms “gastric ulcer” and “duodenal ulcer” refer to peptic ulcers located in the stomach and the first portion of the small intestine, respectively.

Gastroenteritis could involve the stomach, the small intestine, or the large intestine. It is a disorder marked by nausea, vomiting, abdominal discomfort, and diarrhea. The condition has various causes and is known by several names. Bacteria are a common cause of the condition known as food poisoning
. Amoebas, parasites, and viruses can bring about the symptoms associated with intestinal influenza or travelers’ diarrhea. Allergic reactions to food or drugs may cause gastroenteritis.

Although diverticulitis may be found anywhere along the gastrointestinal tract, it is most commonly found in the sigmoid colon. This disorder results from the formation of pouches or diverticula in the wall of the tract. Undigested food and bacteria collect in the diverticula and react to form a hard mass. The mass interferes with the blood supply to the area and ultimately irritates and inflames surrounding tissue. Abscess, obstruction, and hemorrhage may develop. A diet lacking in fiber appears to be the major contributor to this disorder.

Colitis, or inflammation of the bowel, is accompanied by abdominal cramps, diarrhea, and constipation. It may be brought about by psychological stress, as in irritable bowel syndrome, or may be a manifestation of such disorders as chronic ulcerative colitis and Crohn’s disease.

A change in the rate of motility through the colon or large intestine results in one of two disorders: diarrhea or constipation. As food passes through the colon, water is reabsorbed by the body. If the food moves too quickly through the colon, then much of the water will remain in the feces and diarrhea results. Severe diarrhea affects electrolyte balance. Viral, bacterial, and parasitic organisms may initiate the rapid motility of substances through the colon. Another condition, called constipation, develops from sluggish motility. When the food remains for too long a time in the bowel, too much water is reabsorbed by the body. The feces then become dry and hard, and defecation is difficult. Lack of fiber in the diet and lack of exercise are the leading causes of constipation.

Hemorrhoids are varicose veins that develop in the rectum or anal canal. Varicose veins are the result of weakened venous valves. Factors such as pressure, lack of muscle tone as a result of aging, straining at defecation, pregnancy, and obesity are among the common contributors. Hemorrhoids become irritated and bleed when hard stools are passed.

Malignancies can occur at any point along the gastrointestinal tract. Cancers of the mouth are frequently associated with tobacco use. Esophageal cancer may be associated with heavy alcohol use, tobacco, or chronic reflux. Gastric cancer may be the result of chronic ulcer disease or heavy exposure to foods high in nitrites. Colon cancer is one of the leading causes of death in the United States, and it may be associated with certain genetic disorders or might arise spontaneously.

Disorders in the accessory organs contribute to the malfunctioning of the gastrointestinal system. Gallstones, cirrhosis of the liver, pancreatitis, and pancreatic cancer are among the major diseases affecting the digestive process. These disorders generally involve the obstruction of tubes or the destruction of glands, so that enzymes do not reach the intended site of digestion.

Perspective and Prospects

The proper functioning of the gastrointestinal system is dependent on the anatomical structure and health of the organs. The organs provide the site for the mechanical and chemical digestion of food, the absorption of food and water, and the elimination of waste material. Two factors play a primary role in causing anatomical abnormalities in digestion: aging and eating disorders.

The aging process gradually changes anatomical structure. For food to be chewed properly, teeth must be in good health. Dental caries, periodontal disease, and missing teeth prevent the proper mastication of food. Because of these problems, older people tend to avoid foods that require chewing. This may lead to an unbalanced diet. Another age-related change in the mouth is the atrophy of the salivary glands and other secretory glands, which interferes with chemical digestion and swallowing. A loss of muscle tone in the organ walls impedes mechanical digestion and slows down the movement of food through the system. Often, the elimination of waste material becomes difficult and constipation results.

Eating disorders such as anorexia nervosa and bulimia contribute to digestive malfunctioning. These disorders are most often associated with but are not limited to young women. Anorexia is self-imposed starvation, while bulimia is characterized by a binge-purge cycle that incorporates vomiting and/or abuse of laxatives. Both conditions induce nutrient deficiencies and upset water and electrolyte balances. The vomiting of the acid contents of the stomach damages esophageal, pharyngeal, and mouth tissue. It also destroys tooth enamel. In addition to the harm done to the gastrointestinal system, eating disorders affect several other systems, such as the reproductive system.

The field of medical science that studies and diagnoses digestive system disorders is gastroenterology. Gastroenterologists use several investigative techniques. Blood tests and stool examination are used to detect internal bleeding and deficiency disorders. For a time, X rays were the only nonsurgical means of obtaining information on the structure of internal organs. The advent of nuclear medicine
in the 1950s led to the use of radioisotopes in body scanning procedures. Instruments capable of a more detailed and direct visualization were developed, such as fiber optics and the fluoroscope. Fiber optics
involves the use of long, threadlike fibers of glass or plastic that transmit light into the organ and reflect the image back to the viewer; this method allows the physician to detect ulcers, lesions, neoplasms, and structural abnormalities. The fluoroscope uses X rays to permit continuous observation of motion within the organs.

The 1970s saw the development of more sophisticated scanning and imaging techniques. computed tomography (CT) scanning uses X-ray techniques to scan very thin slices of tissue and presents a defined, unobstructed view. Magnetic resonance imaging (MRI) can provide detailed information even to the molecular level; energies from powerful magnetic fields are translated into a visual representation of the structure being studied. Another technique, ultrasonography, passes sound waves through a body area, intercepts the echoes that are produced, and translates them into electrical impulses, which are recorded and interpreted by the physician.

Bibliography

Abrahams, Peter H., Sandy C. Marks, Jr., and Ralph Hutchings. McMinn’s Color Atlas of Human Anatomy. 6th ed. St. Louis, Mo.: Mosby/Elsevier, 2008.

Carson-DeWitt, Rosalyn. "Ulceratuve Colitis." Health Library, September 10, 2012.

Keshav, Satish, and Adam Bailey. The Gastrointestinal System at a Glance. Malden, Mass.: Blackwell, 2013.

Moog, Florence. “The Lining of the Small Intestine.” Scientific American 245 (November, 1981): 154–176.

Shannon, Diane W. "Viral Gastroenteritis." Health Library, September 26, 2012.

Tortora, Gerard J., and Bryan Derrickson. Principles of Anatomy and Physiology. 12th ed. Hoboken, N.J.: John Wiley & Sons, 2009.

Young, Emma. "Alimentary Thinking." New Scientist 2895 (December 15, 2012): 38–42.

Explain the apparent differences between Squealer in Animal Farm and the Russian newspaper, Pravda, as instruments of propaganda.

Firstly, Squealer only became significant as an instrument of propaganda for the pigs after the Rebellion when Mr. Jones and his men were ousted from the farm, whilst Pravda existed long before the February Revolution of 1917. The newspaper had already been established in 1903 when the Tsarist regime was still in power. Squealer only gained importance after Old Major's speech in the big barn, when the animals started preparations towards an overthrow.

Secondly, the newspaper had originally been created as a journal which provided information on the arts, literature, and social life, a type of entertainment tabloid, whilst Squealer had no such function before or after the Rebellion. Although his purpose before the actual revolution was to motivate the animals in preparing for the rebellion, his sole directive, soon after the event, was to convince the other animals that the pigs were acting in their best interest, as is illustrated by his clever explanation for the pigs' exclusive claim to the milk and windfall apples in chapter 3:

"It is for YOUR sake that we drink that milk and eat those apples. Do you know what would happen if we pigs failed in our duty? Jones would come back! Yes, Jones would come back! Surely, comrades," cried Squealer almost pleadingly, skipping from side to side and whisking his tail, "surely there is no one among you who wants to see Jones come back?"  

Another significant distinction between the two is that once it was discovered that Pravda was used to publish political rhetoric, it was banned by the Tsarist government and appeared under various pseudonyms during the period before the Rebellion. Mr. Jones had not at any time suspected that the animals were secretly planning to overthrow the farm and, therefore, had no reason to sanction Squealer or any of the other animals, for that matter.

Furthermore, Pravda was moved to a different country and became a political mouthpiece for a Ukrainian political party, Spilka, which ran its publication from Vienna. It was only in 1912 that Lenin decided to make Pravda his organisation's political mouthpiece. Squealer was always a spokesperson for the pigs only, and never acted on behalf of anyone else. 

Another minor contrast lies in the fact that, essentially, Pravda had been controlled by different masters, such as Lenin and later Stalin. Squealer served only one leader, Napoleon. There had never been any other in control of the farm as it had been in Russia, from before and after the Revolution.

Despite these differences, the overall purposes of both Pravda and Squealer were the same: to propagate a particular political ideology and, more importantly, to confuse and mislead followers into believing that, whatever their leaders did, they did it for the general good by constantly assuring them, through blatant misinformation, that they were better off than they had ever been before.

The 'black box' used in "The Lottery" is a symbol to represent a bigger idea or concept behind this event. What does the black box symbolize?

The black box represents tradition and the people's unwillingness to break or change that tradition. It is noted that some have suggested using a new box. The barbaric ritual would continue, but simply with a newer looking box. But the consensus is that they wouldn't dare change anything about their traditions. So, the notion of a new box is squashed before it can even be debated. Tradition is more important: 

Mr. Summers spoke frequently to...

The black box represents tradition and the people's unwillingness to break or change that tradition. It is noted that some have suggested using a new box. The barbaric ritual would continue, but simply with a newer looking box. But the consensus is that they wouldn't dare change anything about their traditions. So, the notion of a new box is squashed before it can even be debated. Tradition is more important: 

Mr. Summers spoke frequently to the villagers about making a new box, but no one liked to upset even as much tradition as was represented by the black box. There was a story that the present box had been made with some pieces of the box that had preceded it, the one that had been constructed when the first people settled down to make a village here. 

The black box has deteriorated over the years. This symbolizes the deterioration of the ritual. That ritual is a remnant of the past. It had been initiated as some type of sacred ritual to appease God and/or be a sacrifice to promote a good crop. But note that other towns talk of getting rid of the ritual. This suggests that other places are becoming more logical, ethical, and scientific. The ritual always was useless and barbaric, but within the context of a more modern society, the ritual seems even more absurd and out of touch. It's tattered appearance symbolizes how it is a vestige of a less enlightened society. 

The black box represents traditional ways of thinking and people's fear of changing. Note that the villagers don't even know what the ritual is. The only things that they do remember are the stones: 

Although the villagers had forgotten the ritual and lost the original black box, they still remembered to use stones. 

This shows a thoughtless acceptance of tradition, traditional thinking, past ideologies and belief systems. The black box represents tradition and this notion of mindlessly accepting tradition, no matter what the case is. 

What are the effects of supernatural elements in Shakespeare's Julius Caesar?

The supernatural elements create a mood of excitement and suspense, and foreshadow future events.

There are several examples of supernatural events in the play.  The first occurs early on, in the second scene, when Caesar is warned.  The warning nature of the supernatural continues, as the conspirators fear bad omens.  These supernatural events both cause suspense and foreshadow drama to come.

CASSIUS

Fellow, come from the throng; look upon Caesar.

CAESAR

What say'st thou to...

The supernatural elements create a mood of excitement and suspense, and foreshadow future events.

There are several examples of supernatural events in the play.  The first occurs early on, in the second scene, when Caesar is warned.  The warning nature of the supernatural continues, as the conspirators fear bad omens.  These supernatural events both cause suspense and foreshadow drama to come.

CASSIUS

Fellow, come from the throng; look upon Caesar.

CAESAR

What say'st thou to me now? speak once again.

Soothsayer

Beware the ides of March.

CAESAR

He is a dreamer; let us leave him: pass. (Act 1, Scene 2) 

Caesar pays no attention to the soothsayer, but his prediction lets us know that Caesar is in danger.  It foreshadows Caesar’s assassination, because it lets us know that on the Ides of March something terrible will happen.  It sets an ominous tone.  This tells us that all is not well in Rome.

Another example of the supernatural is found in the descriptions some of the conspirators give of weird events that have been happening.  They clearly are fearing what they are about to do, and wonder if these are bad omens.

Are not you moved, when all the sway of earth
Shakes like a thing unfirm? O Cicero,
I have seen tempests, when the scolding winds
Have rived the knotty oaks, and I have seen
The ambitious ocean swell and rage and foam,
To be exalted with the threatening clouds … (Act 1, Scene 3)

These descriptions tell us what kind of men we are dealing with.  They believe in and fear the supernatural.  They fear bad omens.  They perhaps feel guilty about what they are planning.  It creates an ominous atmosphere.

There are more supernatural events referenced in Calpurnia’s dreams.  She too fears for Caesar.  Later, Cassius bemoans the signs he has seen and worries that he will die on his birthday.  Clearly, the supernatural fears influence his decision to kill himself.

 

What are some post-colonial themes in "Passport" by Mahmoud Darwish? How can post-colonialism be applied to this poem?

This is a poem about conflict over identity. This conflict arises when one group, defined here as an outside/anterior group that has claimed local authority, attempts to take ownership of another group's right to self-definition. 

The speaker of the poem implies that his identity is not open to debate because, like the trees and valleys, his identity is a quality beyond the whimsy of policy.

"Don't ask the trees for their names
Don't ask the valleys who their mother is
From my forehead bursts the sward of light
And from my hand springs the water of the river
All the hearts of the people are my identity"

A conflict over self-definition falls squarely into the purview of post-colonial theory, which is interested in the cultural and intellectual ramifications of an occupying authorial force affecting the identity of a native or subjected population. When the colonial group defines the native group according to its own agenda, the colonial/colonizing group is presented as the positive side of a binary value system. 

Frantz Fanon, in particular, codified this behavior as a marker of colonialism in his critical work, which is now central to the canon of post-colonial theory. Fanon suggested that colonizing groups succeeded in turning native populations against themselves internally, forcing them to adopt a value system that deemed them as possessing an inferior identity in comparison to the group in power. 

"One way colonialism achieved this end had been to plant, and then constantly to reinforce, a feeling of inferiority in the mind of the colonized."

In the Darwish poem, we see the right to self-definition being challenged by the colonizing group. The speaker resists and cries out against the theft of his right to define himself. 

The poem's intentions are essentially political in ways that align it with post-colonial literature. The poem's resistance to a loss of authority over self-definition is critical to its message. The poet questions the nature of what he is being forced to do by giving up his passport.

"Stripped of my name and identity?"

More than a loss of mobility that comes with having no passport, the speaker feels that the validity of his identity is being undermined. 

The question of rights raised here is not a purely intellectual question about the esoteric notion of identity. As complex as identity is, as a psychological concept, there is a fundamentally political aspect involved in identity. The politics co-mingle with some of the deeper issues of identity and generate a troubling, schismatic dynamic. 

While it is possible to protest the act of being stripped of a passport, it is more difficult to protest the more ephemeral but deeply felt connotations of the act. 

The limits on the ability to protest on a philosophical level are explored in other post-colonial texts like Things Fall Apart and Waiting for the Barbarians, where we see characters struggle to effectively achieve an internal and integral bulwark against a colonial value system.

In 2014 it was reported that 72% of Australians supported marriage equality. Find the probability that more than 12 out of a randomly selected...

Whenever we need to determine the probability of multiple true/false outcomes (support marriage equality or don't support marriage equality) out of some predetermined number of Bernoulli trials, we are dealing with binomial distribution. 

Probability mass function of binomial random variable is given by

`((n),(k))p^k(1-p)^(n-k)`

where `n` is the number of Bernoulli trials, `k` is number of successful (true) trials and `p` is the probability of success.

In this case

`n=20`

`k>12`

`p=72%=0.72`

Therefore, the probability that more than 12...

Whenever we need to determine the probability of multiple true/false outcomes (support marriage equality or don't support marriage equality) out of some predetermined number of Bernoulli trials, we are dealing with binomial distribution. 

Probability mass function of binomial random variable is given by

`((n),(k))p^k(1-p)^(n-k)`

where `n` is the number of Bernoulli trials, `k` is number of successful (true) trials and `p` is the probability of success.

In this case

`n=20`

`k>12`

`p=72%=0.72`

Therefore, the probability that more than 12 Australians out of 20 support marriage equality will be the sum of the mass function for each `k` between 13 and 20 i.e.

`sum_(k=13)^20 ((20),(k))0.72^k0.28^(20-k)`

For `k=13` we get

`((20),(13))0.72^13 0.28^7=(20cdot19cdot18cdot17cdot16cdot15cdot14cdot)/(1cdot2cdot3cdot4cdot5cdot6cdot7)cdot0.72^13 0.28^7approx0.146165`            

In the line above we have used the fact that `((n),(k))=((n),(n-k))` which can be useful in calculating binomial coefficients.

We proceed by calculating the terms of the sum for all `k=13,14,ldots,20` and then summing all the terms.

Finally we get

`sum_(k=13)^20 ((20),(k))0.72^k0.28^(20-k)\approx0.829272=82.9272%`

Therefore, we can conclude that there is `82.9272%` probability that more than 12 randomly selected Australians in 2014 supported marriage equality. 

If you want to know more about binomial distribution check the links below.        ` <br> `

` `

What are anorexia nervosa and bulimia nervosa?

Introduction

Anorexia nervosa and bulimia nervosa are two types of eating disorders. They are illnesses with a biological basis modified by emotional and cultural factors. Anorexia literally means a severe loss of appetite, while nervosa means nervousness. Actually, the word anorexia is somewhat of a misnomer, given that most people with anorexia nervosa have not lost their appetites.

History of the Disorders

Anorexia is a disorder that can be traced as far back as the twelfth century, when it was associated with religion—saints refused food to get closer to God. The disorder was specifically named as a diagnosis in 1874, when Sir William Gull published an article giving the disorder its present name.

The binge/purge behavior of bulimia has been around for centuries, and bulimia nervosa was identified as a disorder in the 1930s but was thought to be a form of anorexia. Bulimia nervosa was not named as a disorder separate from anorexia until the late 1970s, when both disorders began receiving media attention with stories of girls and women refusing to eat and dying from the behavior. Probably the most famous case at that time was that of Karen Carpenter, a singer who died at age thirty-two of heart failure caused by anorexia. There is evidence to suggest that the incidence of both disorders in the United States has increased since the 1970s. The increased emphasis on thinness within American society is a likely explanation for the increase in eating disorders.

Symptoms

The disorder of anorexia nervosa consists of three prominent symptoms, according to the fifth edition of the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM-5). The first symptom is an abnormally low weight for one’s age, height, and physical condition due to significant restriction of energy intake. Because many people with anorexia nervosa (known as anorectics or anorexics) are secretive about their eating behaviors and cover their weight loss with clothing, they are not diagnosed until they have already lost significant amounts of weight. The second symptom of anorexia nervosa can take the form either of an intense fear of gaining weight or being fat or of behavior that prevents weight gain. This second symptom has been labeled weight phobia
by some researchers because of the anorectic’s anxiety toward food and the desperate attempts the person makes to avoid food. The third major symptom of the syndrome is distorted body image. Distorted body image, which sometimes takes the form of body dysmorphic disorder, involves the anorectic seeing herself or himself as obese when in reality she or he is extremely underweight. Because of this, during treatment, anorectics are not allowed to know their weight. Premenopausal women with anorexia nervosa also often experience the absence of at least three menstrual cycles in a condition known as amenorrhea, which is caused by being severely undernourished. The lack of nutrients affects the hypothalamic, pituitary, gonadal axis, causing the lack of hormones that result in amenorrhea.

Bulimia nervosa refers to the recurring cycle of binge eating, a short period of excessive overeating, followed by purging or other compensatory behaviors as drastic efforts to lose the weight gained by binge eating. For the bulimic, binging has two components: eating large amounts in a limited amount of time and feeling a lack of control while eating. Purging may be accomplished through several means, including vomiting (done either by gagging oneself or through the consumption of certain drugs) and the use of laxatives, diuretics, or enemas; other inappropriate compensatory behaviors include fasting or strict dieting and excessive exercising. To be diagnosed with bulimia, according to the DSM-5, a person must engage in the cycle of binge eating and compensatory behaviors at least once per week, on average, for three months. It is likely that the number of bulimics reported would be higher without this strict criterion. However, bulimia should not be confused with binge eating disorder, which, according to the DSM-5, is characterized by binge eating that is not followed by inappropriate compensatory behaviors such as purging.

Health Problems

Numerous health problems may occur as a result of anorexia or bulimia. The health problems of anorectics include an abnormally low heart rate and low blood pressure as well as irregular heart functioning, often resulting in heart failure. Fatigue is common, and bone thinning (osteopenia) may lead to osteoporotic fractures if left untreated. Dehydration can lead to kidney failure, and lack of body fat combined with the change in hormones makes it difficult to regulate body temperature. Anorectics may develop lanugo hair over their bodies, including the face, to help with temperature regulation. The death rate for anorexia nervosa is one of the highest for any mental health condition, and generally, the longer the condition lasts, the higher the death rate.

Most of the health complications of bulimia are related to the purging behaviors. Electrolyte imbalances, particularly potassium reduction, can occur from all purging behaviors and can lead to irregular heartbeats and possibly heart failure and death. Vomiting leads to the erosion of tooth enamel and a variety of disorders affecting digestive organs. A significantly lower number of people are thought to die from bulimia as compared with anorexia. Those with binge eating disorder exhibit the same health consequences as anyone with obesity, so heart disease and type 2 diabetes are common.

When compared with obesity, which in some cases can be the result of an eating disorder, anorexia and bulimia are rare. According to a 2012 report by the Centers for Disease Control and Prevention, approximately 35.7 percent of American adults and 16.9 percent of American children are obese. In contrast, an estimated 0.6 percent of American adults will have anorexia during their life, according to 2007 statistics compiled by the National Institute of Mental Health. The incidence of anorexia among adolescents, especially female adolescents, however, is significantly higher than in the general population. Bulimia is likewise estimated to occur in 0.6 percent of American adults, and again, the incidence of bulimia among adolescents is estimated to be significantly higher. A subpopulation in which the incidence of eating disorders is higher is athletes. The type of eating disorder seems to correlate with the sport. In individual sports, in which lower weight is an advantage or looks are a factor, anorexia is more common, and in team sports, bulimia is more common. Male and female athletes show similar rates of eating disorders because the disorders are related to the sport and athletic performance.

Causes and Explanations

The proposed causes of anorexia and bulimia can be grouped into four categories: biological, sociocultural, familial, and psychological. The notion of biological causes of anorexia and bulimia involves the idea that anorectics and bulimics have specific brain or biochemical disturbances that lead to their inability to maintain a normal weight or eating pattern. One biological explanation researched for the occurrence of anorexia and bulimia is the existence of an abnormal amount of certain brain neurotransmitters, especially norepinephrine and serotonin. Neurotransmitters are chemical messengers within the brain that transmit nerve impulses between nerve cells.

In contrast to biological explanations, sociocultural causes are factors that are thought to exist within a society that lead certain individuals to develop anorexia or bulimia. Joan Brumberg, a historian of anorexia, has outlined the sociocultural forces of the late nineteenth and twentieth centuries that many believe promoted the increased incidence of eating disorders among women. These societal forces included an emphasis on weight reduction and aesthetic self-control and the treatment of women as sexual objects. The most prominent of these suggested cultural factors is the heightened importance placed on being thin.

Some researchers believe that particular family types cause certain of their members to develop anorexia and bulimia. For example, family investigators believe that a family whose members are emotionally too close to one another may lead one or more family members to strive for independence by refusing to eat, according to Salvador Minuchin, Bernice Rosman, and Lester Baker. Other researchers believe that families whose members are controlling and express an excessive amount of hostility toward one another promote the occurrence of bulimia. Some research also shows genetic tendencies; that is, if a parent had an eating disorder, it is more likely that one or more of his or her children will also be diagnosed with one, even if the parent is no longer exhibiting symptoms.

The most prominent of the suggested psychological causes for anorexia and bulimia are those expressed by researchers who take psychoanalytic or cognitive behavioral perspectives. For example, cognitive behavioral theorists emphasize the role of distorted beliefs in the development and continuation of anorexia and bulimia. These distorted beliefs include that the person is attractive only if she or he weighs a certain number of pounds, usually a number well below normal weight, or that consuming certain types of foods (such as carbohydrate-rich foods) will automatically make a person fat.

Treatments

Numerous treatments have been used for individuals who have anorexia or bulimia, but they can be broadly grouped into the categories of medical and psychological therapies. If symptoms are life threatening, these disorders are treated in a hospital, and if they are more manageable, these disorders can be treated on an outpatient basis.

Before the 1960s, medical therapies for anorexia included such radical approaches as lobotomies and electroconvulsive therapy (ECT). The first goal for the treatment of anorexia is to ensure the person’s physical health, which involves restoring the person to a healthy weight. Reaching this goal may require hospitalization. Although a controversial treatment, various types of tube feeding continue to be used when a patient’s malnutrition from anorexia poses an imminent risk of death. Tube feeding can be accomplished either intravenously or by inserting a tube via a patient’s nasal cavity into the patient’s stomach.

Once a person’s physical condition is stable, treatment usually involves individual psychotherapy and family therapy, during which parents help their children learn to eat again and maintain healthful eating habits on their own.
Behavioral therapy also has been effective for helping anorectics return to healthful eating habits. Supportive group therapy may follow, and self-help groups within communities may provide ongoing support. There are a number of in-patient treatment facilities that specialize in anorexia throughout the United States. The most effective treatment no matter the location is team treatment addressing all three areas of concern. A physician treats the medical conditions and potentially the mental aspects if drugs are required, a counselor manages the behavioral aspect, and a dietician manages the dietary component.

When treating bulimia, unless malnutrition is severe, any substance abuse problems that may be present at the time the eating disorder is diagnosed are usually treated first. The next goal of treatment is to reduce or eliminate the person’s binge eating and purging behavior. Behavioral therapy has proven effective in achieving this goal. Psychotherapy has proven effective in helping prevent the eating disorder from recurring and in addressing issues that led to the disorder. Studies have also found that fluoxetine (Prozac), an antidepressant, may help people who do not respond to psychotherapy. Some bulimics also exhibit obsessive-compulsive disorder (OCD), and drugs appropriate for OCD also help reduce the bulimic behaviors. As with anorexia, family therapy is also recommended.

The family treatment of anorectics involves the therapist seeking to change the interactions among family members that serve to maintain the self-starvation of the patient. In attempting to change family interactions, the family therapist might address the parents’ overprotectiveness or the way family members manipulate one another’s behavior. For bulimics, the family therapist would seek to lower the amount of family conflict or to redirect conflict between the parents away from the bulimic.

Another frequently employed method of treatment for bulimia is group therapy. Group treatment initially involves educating bulimics about their disorder, including its negative health consequences. The group experience provides members with the opportunity to share with fellow bulimics regarding their eating problems and to find support from one another in overcoming bulimia. In addition, the therapist or therapists initiate discussions regarding healthful eating and exercise habits as well as specific ways to end the cycle.

A final issue involved in surveying the different interventions for anorexia and bulimia is the effectiveness of these treatments. A meta-analysis of one hundred studies of anorectics in 1988 found only small differences between the various types of treatment in the amount of weight gained during therapy, although behavioral treatments appeared to work faster. A negative impact of changes in health insurance coverage for anorectics has been shorter treatment times and poorer outcomes. Definitive research shows that the closer anorectics are to their ideal weight on discharge, the less likely they are to be readmitted, even if that requires a longer treatment initially. Managed care generally allows a certain amount of time or certain number of treatment sessions rather than basing coverage on return to normal weight.

Less research has been conducted investigating the effectiveness of different therapies for bulimia. No single therapy for bulimia, however, whether medical or psychological, has shown clear superiority in its effectiveness as compared with other interventions. More important was when treatment began. Patients with bulimia nervosa demonstrated a better recovery rate if they received treatment early in their illness.

Prevention and Remaining Questions

Research has begun to focus on the prevention of eating disorders. Catherine Shisslak and colleagues have suggested that preventive efforts should be targeted at female adolescents, given that they are at increased risk for developing an eating disorder. One of the most important ideas that has come out of research on eating disorders is that outcomes are much better when treatment begins early. Research also suggests that if the disordered eating behaviors are caught when they begin and before they have reached diagnostic criteria, development of the eating disorder may be prevented. These preventive efforts should focus on issues such as the physical, emotional, and social changes that occur in maturation. Also, information regarding diet and exercise should be provided, and the connection between emotions and eating should be discussed, as should ways to resist the pressure to conform to peers’ and societal expectations regarding appearance.

With evidence of the increasing prevalence of anorexia and bulimia and binge eating disorder, it is important to learn more regarding the causes and effective treatment methods of these disorders. Some of the questions that remain to be definitively answered are why certain groups have a greater likelihood of developing anorexia and bulimia (notably, white female adolescents), whether the underlying causes of anorexia are different from those of bulimia, and whether a more effective treatment can be developed for those with anorexia or bulimia.

Bibliography

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Walsh, Timothy B. “Fluoxetine for Bulimia Nervosa Following Poor Response to Psychotherapy.” American Journal of Psychiatry 157 (2000): 1332–34. Print.

What is evolutionary psychology? |

Introduction

Humans share with other mammals basic behaviors, motivations, and emotions, but only humans can reflect on and discuss their behaviors, motivations, and emotions, and only humans can influence the behaviors, motivations, and emotions of others through such abstract concepts as appeals to duty, religion, laws, blackmail, promises, and lies. Like other psychologists, evolutionary psychologists study the brain structures and mental functions that underlie these capacities. Unlike other psychologists, evolutionary psychologists begin with the assumption that human mental capacities evolved through natural selection
the same way that human bodies did—that is, that the brain circuitry and processes underlying thought and behavior exist because they somehow helped human ancestors to survive and reproduce. It is this perspective, rather than research topics or methodology, that differentiates evolutionary psychology from other fields and approaches in psychology.

Arguing from this perspective, evolutionary psychologists have suggested that the aspects of brain and behavior that consistently conferred the greatest advantages on human ancestors are those that are most likely to now be automatic—that is, subconscious or instinctive. People do not need to be aware of how they avoid large moving objects, for example, as long as they can do it. The corollary line of reasoning is that those aspects of brain and behavior that are now the most automatic are likely to be those that had the greatest and most consistent advantages in the past. For this reason, it is the instinctive and automatic behaviors, as well as the subconscious bases of thoughts and feelings, that have received the most attention from evolutionary psychologists.

Sensation, Perception, and Hedonic Preferences

Certain important aspects of the behavior of the physical world seem to be innately wired into, or easily acquired by, the human brain. Babies experience anxiety about steep drop-offs as soon as they can see them, without having to learn by experiencing a fall. They also flinch or move away from objects that are getting larger on a projection screen and therefore appear to be coming toward them. Although babies cannot count or do math, they very quickly appreciate such fundamental concepts as length, mass, speed, and gravity, as well as the concepts of more and less and larger and smaller. They typically acquire an easy grasp of one of the most abstract concepts of all: time.

Humans also exhibit innate preferences for things that were “good” for human ancestors and a dislike of things that were “bad.” People naturally like sweet foods that provide them with the necessary glucose for their calorie-hungry brains and salty foods that provide them with the minerals to run their neuronal sodium-pump, yet they have to acquire (and may never acquire) a taste for bitter and foul-smelling foods, which signal their brains that the substance may contain toxins. The human brain also automatically causes people to develop intense aversions
to foods that were ingested several hours before becoming ill. Even in cases when a person consciously knows that it was not that food that actually caused the sickness, the very thought of that item may cause nausea ten years after an illness.

Humans are also wired for other kinds of “taste.” Children around the world prefer parklike landscapes that provide plenty of water and trees and forms of play that provide exercise, strengthen muscles, and increase physical coordination. Adults admire the beautiful faces and shapely bodies of the young, healthy, and disease-free—those who are the safest friends and most profitable mates. In sum, experiences of pain or disgust signal that something is potentially dangerous and is to be avoided; experiences of pleasure or admiration signal safety or opportunity and encourage a person to approach.

Emotion, Motivation, and Attachment

Important emotions, too, appear early in life, without having to be learned. These so-called primary emotions include fear, anger, happiness, sadness, surprise, and disgust. Like tastes, emotions serve as signals to alert the conscious awareness about important stimuli, but they also serve as signals to others. The facial expressions that accompany primary emotions are performed consistently across cultures, even in children blind from birth. People instinctively understand the facial expressions signifying emotion and pay special attention when they see them.

Perhaps the most important emotion for survival and reproduction is the
attachment that develops between an infant and its mother.
Human infants are completely dependent on parental care and, even after weaning, require intensive investment and supervision. It is thus in the interest of both mother and child that a close bond form between them, to keep the child from wandering away and to keep the mother motivated to address the constant demands of her offspring. Infants can recognize their mother’s voice and smell soon after birth and, as soon as their eyes are able to focus, can recognize—and show preference for—her face. Once they are old enough to crawl, babies develop an intense desire to be within sight of their mother and, when temporarily separated, experience and communicate great distress. Mothers, reciprocally, develop an intense attachment to their children, and they, too, experience distress on separation.

Other social emotions also motivate people to repeat mutually beneficial interactions and to avoid people who might take advantage of them. Guilt and shame are cross-cultural universals that indicate disgust toward one’s own behavior and signal to others that one is unlikely to repeat the “rotten” behavior; allegiance and sympathy signal a willingness to help allies when in need; and vengeance and hatred warn those who have harmed someone that they endanger themselves if they approach again.

Personality, Sex Differences, and Social Relations

Predicting other people’s behavior is important, so any aspect of a person that is consistent and can help a person to predict accurately becomes worthy of attention. One source of predictability derives from consistent personality differences between the sexes. Boys and men around the world are, on average, more physically aggressive, more competitive, more impulsive, and more risk-prone than girls and women, who are, on average, more nurturant, more empathetic, more cooperative, and more harm-avoidant than boys and men. These differences have impacts on social behavior across the life span, influencing patterns of early childhood play, courtship, parenting, career choice, and participation in warfare, crime, and other high-risk activities.

In addition to sex differences, there are two major dimensions of personality that seem of particular importance: dominance/submissiveness and friendliness/hostility. As with tastes and emotions, one’s assessment of another person’s personality seems to highlight “good/safe” versus “bad/dangerous” and signals to approach or avoid, respectively. It seems that people attend to personality to determine who is likely to be a friend, to be trustworthy, and to be helpful, versus who is likely to hurt, to betray, and to take advantage.

In fact, it might have been the need to predict how other people might respond that led to human beings’ great intelligence. Like other social species, humans constantly monitor the statuses of those around them: who is fighting, who is having sex, who is popular, who is not. Compared with other animals, however, humans have taken this kind of mental tracking to a level that is quite complex: a man can think about what a friend might think if his sister told him that she heard that he knew that his girlfriend had heard a rumor that he was seeing someone else but that he had not told him . . . and so on. Such multilevel cogitation requires a great deal of long-term and short-term memory, as well as an extensive ability to manipulate concepts and scenarios.

Learning, Language, and Thinking

Given humans’ great intellectual capacity, evolutionary psychologists do not claim that all knowledge is inborn—it is obvious that humans acquire much information through learning. Nonetheless, evolutionary psychologists note that certain types of information are more easily learned than others.

Language, for example, is a kind of complex and abstract knowledge that comes as second nature to very young children. Across all cultures and languages, children progress through regular stages of language development, acquiring the ability to both understand and produce grammatical speech (or, in the case of deaf children, visual signs). At their peak, children actually acquire several new words an hour. Most adults, on the other hand, have to work extremely hard to acquire a second or third language, and it is exceedingly difficult to teach even the smartest computers and robots how to understand elementary forms of speech. Language is an example of a highly specialized kind of learning that is prewired into the human brain; it is acquired quickly during a critical period of brain development, and once achieved, it is never forgotten.

Similarly, humans readily develop mental stereotypes
that, once acquired, are difficult or impossible to disregard. Stereotypes are, basically, abstract generalizations that arise from the subconscious integration of personal and vicarious experience. Like tastes, emotions, and attention to personality, the automatic generation of stereotypes helps a person to respond quickly and appropriately to new stimuli without wasting precious time assessing each nuance of each situation encountered each new minute of every day.

Applied Evolutionary Psychology

Evolutionary psychologists do not claim that behavior that was once adaptive is necessarily still adaptive, nor that behavior that has evolved is unchangeable. For example, while stereotypes were designed to work to a person’s advantage, the experiences that now go into one’s mental computations include not only real experiences but also thousands of images from movies, newspapers, and television. As a result, stereotypes reflect not necessarily reality and true experience but rather the biases of the society at large, often amplified in the make-believe world of Hollywood. Taking an evolutionary approach to psychology suggests that although people will continue to create stereotypes, by changing or monitoring media coverage, increasing exposure to positive images, or broadcasting the voices of the unheard, the content of stereotypes could be changed. Like other approaches to psychology, evolutionary psychology has practical implications that can help people to understand—and improve—the human condition.

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Workman, Lance, and Will Reader. Evolutionary Psychology. New York: Cambridge UP, 2014. Print.