26. - NUTRITION AND METABOLISM

26. - NUTRITION AND METABOLISM

Eating disorders refer to a group of conditions defined by abnormal eating habits that may

involve either insufficient or excessive food intake to the detriment of an individual's physical and mental health. Bulimia nervosa, anorexia nervosa, and binge eating disorder are the most common specific forms in the United Kingdom. Though primarily thought of as affecting females (an estimated 5–10 million being affected in the U.K.), eating disorders affect males as well. An estimated 10 – 15% of people with eating disorders are males (Gorgan, 1999). (an estimated 1 million U.K. males being affected). Although eating disorders are increasing all over the world among both men and women, there is evidence to suggest that it is women in the Western world who are at the highest risk of developing them and the degree of westernization increases the risk. Nearly half of all Americans personally know someone with an eating disorder. The skill to comprehend the central processes of appetite has increased tremendously since leptin was discovered, and the skill to observe the functions of the brain as well.  
The precise cause of eating disorders is not entirely understood, but there is evidence that it may be linked to other medical conditions and situations. Cultural idealization of thinness and youthfulness have contributed to eating disorders affecting divers populations. One study showed that girls with ADHD have a greater chance of getting an eating disorder than those not affected by ADHD. Another study suggested that women with PTSD, especially due to sexually related trauma, are more likely to develop anorexia nervosa. One study showed that foster girls are more likely to develop bulimia nervosa. Some think that peer pressure and idealized body-types seen in the media are also a significant factor. Some research shows that for some people there is a genetic reason why they may be prone to developing an eating disorder.

While proper treatment can be highly effective for many of the specific types of eating disorder, the consequences of eating disorders can be severe, including death (whether from direct medical effects of disturbed eating habits or from comorbid conditions such as suicidal thinking).

ANOREXIA NERVOSA

Anorexia nervosa is an eating disorder characterized by excessive food restriction and irrational fear of gaining weight, and a distorted body self-perception. It typically

involves excessive weight loss. Anorexia nervosa usually develops during adolescence and early adulthood. Due to the fear of gaining weight, people with this disorder restrict the amount of food they consume. This restriction of food intake causes metabolic and hormonal disorders. Outside of medical literature, the terms anorexia nervosa and anorexia are often used interchangeably; however, anorexia is simply a medical term for lack of appetite. However, people with anorexia nervosa do not lose their appetites.
People suffering from anorexia have extremely high levels of ghrelin, the hunger hormone that tells the brain when it is time to eat, in their blood. The high levels of ghrelin suggests that their bodies are trying desperately to switch hunger on but that hunger’s call is being suppressed, ignored, or overridden. Nevertheless, one small single-blind study found that intravenous administration of ghrelin to anorexia nervosa patients increased food intake by 12-36% over the trial period.
Anorexia nervosa has many complicated implications and may be thought of as a lifelong illness that may never be truly cured, but only managed over time. Anorexia nervosa is characterized by low body weight, inappropriate eating habits and obsession with having a thin figure. Individuals suffering from it may also practice repeated weighing, measuring, and mirror gazing, alongside other obsessive actions, to make sure they are still thin, a common practice known as "body checking".

Anorexia nervosa is often coupled with a distorted self image which may be maintained by various cognitive biases that alter how the affected individual evaluates and thinks about her or his body, food and eating. Anorexia nervosa is characterized by the fear of gaining weight. Those suffering from this disorder often view themselves as "too fat" even if they are already underweight. Persons with anorexia nervosa continue to feel hunger, but deny themselves all but very small quantities of food. The average caloric intake of a person with anorexia

nervosa is 600–800 calories per day, but extreme cases of complete self-starvation are known. It is a serious mental illness with a high incidence of comorbidity and similarly high mortality rates to serious psychiatric disorders.
Anorexia nervosa most often has its onset in adolescence and is more prevalent among adolescent girls than adolescent males. However, more recent studies show the onset age has decreased from an average of 13 to 17 years of age to 9 to 12. While it can affect men and women of any age, race, and socioeconomic and cultural background, anorexia nervosa occurs in 10 times more females than males.
The term anorexia nervosa was established in 1873 by Sir William Gull, one of Queen Victoria's personal physicians. The term is of Greek origin: an- (ἀν-, prefix denoting negation) and orexis (ὄρεξις, "appetite"), thus meaning a lack of desire to eat. However, while the term "anorexia nervosa" literally means "neurotic loss of appetite", the literal meaning of the term is somewhat misleading. Many anorexics do enjoy eating and have certainly not lost their appetites as the term "loss of appetite" is normally understood; it is better to regard anorexia nervosa as a self-punitive addiction to fasting, rather than a literal loss of appetite.
Schneer suggested anorexia nervosa patients who have "difficulties in identifying, containing and articulating emotions resort to food as a symbolic expression of the inability to establish subjective limits in their relationships with others".

BULIMIA NERVOSA

Bulimia nervosa is an eating disorder characterized by binge eating and purging, or consuming a large amount of food in a short amount of time, followed by an attempt to rid

oneself of the food consumed (purging), typically by vomiting, taking a laxative or diuretic and/or excessive exercise, and commonly accompanied with fasting over an extended period of time. Bulimia nervosa is considered to be less life threatening than anorexia; however, the occurrence of bulimia nervosa is higher. Bulimia nervosa is nine times more likely to occur in women than men (Barker 2003). The vast majority of those with bulimia nervosa are at normal weight. Antidepressants, especially SSRIs, are widely used in the treatment of bulimia nervosa (Newell and Gournay 2000). Patients who have bulimia nervosa are often linked with having impulsive behaviors involving overspending and sexual behaviors as well as having family histories of alcohol and substance abuse, and mood and eating disorders.

The term bulimia comes from Greek βουλιμία (boulīmia; ravenous hunger), a compound of βους (bous), ox + λιμός (līmos), hunger. Bulimia nervosa was named and first described by the British psychiatrist Gerald Russell in 1979. Bulimia is strongly familial. Twin studies estimate the heritability of syndromic bulimia to be 54-83%

Signs and symptoms

These cycles often involve rapid and out-of-control eating, which may stop when the bulimic is interrupted by another person or the stomach hurts from over-extension, followed by self-induced vomiting or other forms of purging. This cycle may be repeated several times a week or, in more serious cases, several times a day, and may directly cause:

• Chronic gastric reflux after eating
• Dehydration and hypokalemia caused by frequent vomiting
• Electrolyte imbalance, which can lead to cardiac arrhythmia, cardiac arrest, and even death
• Esophagitis, or inflammation of the esophagus
• Boerhaave syndrome, a rupture in the esophageal wall due to vomiting
• Oral trauma, in which repetitive insertion of fingers or other objects causes lacerations to the lining of the mouth or throat
• Gastroparesis or delayed emptying
• Constipation
• Infertility
• Enlarged glands in the neck, under the jaw line
• Peptic ulcers
• Calluses or scars on back of hands due to repeated trauma from incisors
• Constant weight fluctuations are common

The erosion on the lower teeth was caused by Bulimia. For comparison, the upper teeth were restored with porcelain veneers.

The frequent contact between teeth and gastric acid, in particular, may cause:

• Severe dental erosion
• Perimolysis, or the erosion of tooth enamel
• Swollen salivary glands
• Constant vomiting can lead to gastroesophageal reflux

As with many psychiatric illnesses, delusions can occur with other signs and symptoms leaving the person with a false belief that is not ordinarily accepted by others.
The person may also suffer physical complications such as tetany, epileptic seizures, cardiac arrhythmias and muscle weakness.(ICD-10)^.
People with bulimia nervosa may also exercise to a point that excludes other activities

DIET

A diet is the set of nutrients taken during the habitual consumption of food. Popularly, and in the case of the human diet is erroneously associated with the practice of restricting the intake of food for only the nutrients and energy needed, and thus achieve or maintain a certain body weight.

The human diet is considered balanced if it provides nutrients and energy in such quantities that allow maintaining the functions of the organism in a context of physical and mental health. This balanced diet is particular to every individual and adapts to their sex, age, weight and health situation. However, there are various factors (social, geographical, economic, pathological, etc.) that influence the balance of the diet

Etymologically the word 'diet' comes from the Greek dayta, which means 'regime of life'. It is accepted as a synonym for diet, which alludes to the 'set and amounts of food or mixtures of foods commonly consumed'. You can also refer to the regime which, under certain circumstances, made people healthy, sick or convalescing in eating, drinking and sleeping

29.- EMBRYOLOGY

29.- EMBRYOLOGY

Embryology (from Greek ἔμβρυον, embryon, "the unborn, embryo"; and -λογία, -logia) is a science which is about the development of an embryo from the fertilization of the ovum to the fetus stage.

PREGNANCY

Pregnancy is the fertilization and development of one or more offspring, known as an embryo

or fetus, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets. Childbirth usually occurs about 38 weeks after conception; in women who have a menstrual cycle length of four weeks, this is approximately 40 weeks from the start of the last normal menstrual period (LNMP). Human pregnancy is the most studied of all mammalian pregnancies. Conception can be achieved through sexual intercourse or assisted reproductive technology.

An embryo is the developing offspring during the first 8 weeks following conception, and subsequently the term fetus is used henceforth until birth. 40% of pregnancies in the United States and United Kingdom are unplanned, and between a quarter and half of those unplanned pregnancies were unwanted pregnancies.

In many societies’ medical or legal definitions, human pregnancy is somewhat arbitrarily divided into three trimester periods, as a means to simplify reference to the different stages of prenatal development. The first trimester carries the highest risk of miscarriage (natural death of embryo or fetus). During the second trimester, the development of the fetus can be more easily monitored and diagnosed. The beginning of the third trimester often approximates the point of viability, or the ability of the fetus to survive, with or without medical help, outside of the uterus.

DRUG

A drug, broadly speaking, is any substance that, when absorbed into the body of a living organism, alters normal bodily function. There is no single, precise definition, as there are

different meanings in drug control law, government regulations, medicine, and colloquial usage.

In pharmacology, a drug is "a chemical substance used in the treatment, cure, prevention, or diagnosis of disease or used to otherwise enhance physical or mental well-being." Drugs may be prescribed for a limited duration, or on a regular basis for chronic disorders.

The molecules of drugs are complex, and most of them consist of many hydrogen and carbon atoms, a few oxygen atoms, and one or a few nitrogen atoms. Drugs may also have no nitrogen atoms in it and many may have chlorine atoms in it, such as chloral hydrate.

Recreational drugs are chemical substances that affect the central nervous system, such as opioids or hallucinogens.They may be used for perceived beneficial effects on perception, consciousness, personality, and behavior. Some drugs can cause addiction and/or habituation.
Drugs are usually distinguished from endogenous biochemicals by being introduced from

outside the organism. For example, insulin is a hormone that is synthesized in the body; it is called a hormone when it is synthesized by the pancreas inside the body, but if it is introduced into the body from outside, it is called a drug. Many natural substances, such as beers, wines, and psychoactive mushrooms, blur the line between food and recreational drugs, as when ingested they affect the functioning of both mind and body and some substances normally considered drugs such as DMT (Dimethyltryptamine) are actually produced by the human body in trace amounts.

CONGENITAL ABNORMALITY

A congenital anomaly (congenital abnormality, congenital malformation, birth defect) is a condition which is present at the time of birth which varies from the standard presentation. It is a type of congenital disorder which is primarily structural in nature

AGING AND DEATH

Aging (American English, occasionally British English) or ageing (British English) is the accumulation of changes in a person over time. Aging in humans refers to a multidimensional process of physical, psychological, and social change. Some dimensions of aging grow and expand over time, while others decline. Reaction time, for example, may slow with age, while knowledge of world events and wisdom may expand. Research shows that even late in life, potential exists for physical, mental, and social growth and development. Aging is an important part of all human societies reflecting the biological changes that occur, but also reflecting cultural and societal conventions. Roughly 100,000 people worldwide die each day of age-related causes.

DEATH

Death is the cessation or permanent termination of all biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, suicide, murder and accidents or trauma resulting in terminal injury. All known organisms inevitably experience death. Bodies of living organisms begin to decompose shortly after death. In human societies, the nature of death has for millennia been a concern of the world's religious traditions and of philosophical inquiry. This may include a belief in some kind of resurrection (associated with Abrahamic religions), reincarnation (associated with Dharmic religions), or that consciousness permanently ceases to exist, known as "oblivion" (often associated with atheism). Commemoration ceremonies after death may include various mourning or funeral practices. The physical remains of a person, commonly known as a corpse or body, are usually interred whole or cremated, though among the world's cultures there are a variety of other methods of mortuary disposal