The sign is named after Paul Julius Möbius.
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The sign is named after Paul Julius Möbius.
|This medical sign article is a stub. You can help Wikipedia by expanding it.|
1. Vergence – A vergence is the simultaneous movement of both eyes in opposite directions to obtain or maintain single binocular vision. When a creature with binocular vision looks at an object, the eyes must rotate around a vertical axis so that the projection of the image is in the centre of the retina in both eyes. To look at a closer by, the eyes rotate towards each other. Exaggerated convergence is called cross eyed viewing, when looking into the distance, the eyes diverge until parallel, effectively fixating the same point at infinity. Vergence movements are connected to accommodation of the eye. As opposed to the 500°/s velocity of saccade movements, vergence movements are far slower, the extraocular muscles may have two types of fiber each with its own nerve supply, hence a dual mechanism. The following types of vergence are considered to act in superposition, Tonic vergence, vergence due to normal extraocular muscle tone, with no accommodation, Tonic vergence is considered to move the eyes from an anatomical position of rest to the physiological position of rest. Fusional vergence, vergence induced by a stimulus to binocular fusion, proximal vergence, vergence due to the awareness of a fixation object being near or far in the absence of disparity and of cues for accommodation. This includes also vergence that is due to an intent to fixate an object in the dark. Acommotative vergence is measured as the ratio between how much convergence takes place for a given accommodation, proximal vergence is sometimes also called voluntary vergence, which however more generally means vergence under voluntary control and is sometimes considered a fifth type of vergence. Voluntary vergence is also required for viewing autostereograms as well as for voluntary crossing of the eyes, voluntary convergence is normally accompanied by accommodation and miosis, often however, with extended practice, individuals can learn to dissociate accommodation and vergence. Vergence is also denoted according to its direction, horizontal vergence, vertical vergence, horizontal vergence is further distinguished into convergence or divergence. Vergence eye movements result from the activity of six extraocular muscles and these are innerved from three cranial nerves, the abducens nerve, the trochlear nerve and the oculomotor nerve. Horizontal vergence involves mainly the medial and lateral rectus, in ophthalmology, convergence is the simultaneous inward movement of both eyes toward each other, usually in an effort to maintain single binocular vision when viewing an object. This is the eye movement that is not conjugate. Convergence is one of three processes an eye does to properly focus an image on the retina, in each eye, the visual axis will point towards the object of interest in order to focus it on the fovea. This action is mediated by the rectus muscle, which is innervated by Cranial nerve III. It is a type of eye movement and is done by extrinsic muscles
2. TheFreeDictionary.com – TheFreeDictionary. com is an American online dictionary and encyclopedia that gathers information from a variety of sources. It has a feature allows a user to preview an article while positioning the mouse cursor over a link. One can also click on any word and look it up in the dictionary. The site is run by Farlex, Inc. located in Huntingdon Valley, Wikipedia content is hosted at the sub-domain encyclopedia. thefreedictionary. com, which is excluded from search-engine indexing in its entirety by Farlex with the use of meta tags. This is done to avoid duplicate content in the search-engine results, TheFreeLibrary. com is a free reference website that offers full-text versions of classic literary works by hundreds of authors. It is also a news aggregator, offering articles from a collection of periodicals containing over four million articles dating back to 1984. Newly published articles are added to the site daily, the site comprises a selection of articles from open-access journals that can in many cases also be found on a journals own website. It is a site to TheFreeDictionary. com and usage examples in the form of references in classic literature taken from the sites collection are used on TheFreeDictionary. coms definition pages. In addition, double-clicking on a word in the collection of reference materials brings up the words definition on TheFreeDictionary. com. List of online dictionaries List of online encyclopedias TheFreeDictionary. com TheFreeLibrary. com
3. Endocrine system – The endocrine system is the collection of glands of an organism that secrete hormones directly into the circulatory system to be carried towards distant target organs. The phenomenon of biochemical processes serving to regulate distant tissues by means of directly into the circulatory system is called endocrine signaling. The major endocrine glands include the pineal gland, pituitary gland, pancreas, ovaries, testes, thyroid gland, parathyroid gland, the endocrine system is in contrast to the exocrine system, which secretes its hormones to the outside of the body using ducts. The endocrine system is a signal system like the nervous system, yet its effects. The endocrine systems effects are slow to initiate, and prolonged in their response, the nervous system sends information very quickly, and responses are generally short lived. In vertebrates, the hypothalamus is the control center for all endocrine systems. The field of study dealing with the system and its disorders is endocrinology. Special features of endocrine glands are, in general, their ductless nature, their vascularity, in contrast, exocrine glands, such as salivary glands, sweat glands, and glands within the gastrointestinal tract, tend to be much less vascular and have ducts or a hollow lumen. For example, the kidney secretes endocrine hormones such as erythropoietin and renin, hormones can consist of either amino acid complexes, steroids, eicosanoids, leukotrienes, or prostaglandins. A number of glands that signal each other in sequence are referred to as an axis, for example. The word endocrine derives from the Greek words ἐνδο- endo- inside, within, the pituitary gland is an endocrine gland about the size of a pea and weighing 0.5 grams in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain, the pituitary is functionally connected to the hypothalamus by the median eminence via a small tube called the infundibular stem or pituitary stalk. Oxytocin and anti-diuretic hormone are not secreted in the posterior lobe, the pancreas is a mixocrine gland and it secretes both enzymes and hormones. In 1998, skeletal muscle was identified as an organ due to its now well-established role in the secretion of myokines. The use of the term myokine to describe cytokines and other peptides produced by muscle as signalling molecules was proposed in 2003, signalling molecules released by adipose tissue are referred to as adipokines. The human endocrine system consists of several systems that operate via feedback loops, several important feedback systems are mediated via the hypothalamus and pituitary. Cortisol has major effects, and dopamine has immunomodulatory functions. On the other hand, cytokines produced during inflammation activate the HPA axis at all three levels, sensible to negative feedback, moreover, cytokines stimulate hepcidin release from the liver, which is eventually responsible for the anemia of chronic disease
4. Weight gain – Weight gain is an increase in body weight. This can involve an increase in mass, fat deposits. Weight gain can be a symptom of a medical condition. If enough weight is gained due to increased body fat deposits, one may become overweight or obese, the Body Mass Index measures body weight in proportion to the square of height and defines optimal, insufficient, and excessive weight based on the ratio. Weight gain has a latency period, typical latency periods vary from three days to two weeks after ingestion. Having excess adipose tissue is a condition, especially where food supplies are plentiful. As much as 64% of the United States adult population is considered overweight or obese. A commonly asserted rule for weight gain or loss is based on the assumption that one pound of human fat tissue contains about 3,500 kilocalories, thus, eating 500 fewer calories than one needs per day should result in a loss of about a pound per week. Similarly, for every 3500 calories consumed above the amount one needs and he notes that previous research suggested that a pound of human adipose tissue is 87% fat, which equals 395 grams of fat. He further assumes that animal fat contains 9.5 calories per gram, thus one pound of human fat tissue should contain 3750 calories. He concludes that a 3500 calorie excess or deficit for a person meeting his assumptions, would lead to the gain or loss, respectively, of one pound of body weight. He notes that if the assumptions he makes are not met, in any case, Wishnofsky did not take into account numerous aspects of human physiology and biochemistry which refute this simple equivalence. Unfortunately, the claim has achieved the status of a rule of thumb and is repeated in numerous sources, used for planning by dietitians. In regard to adipose tissue increases, a person gains weight by increasing food consumption, becoming physically inactive. When energy intake exceeds energy expenditure, the body can store the energy as fat. However, the physiology of weight gain and loss is complex involving numerous hormones, body systems, the human microbiota facilitates fermentation of indigestible carbohydrates to short-chain fatty acids, SCFAs, contributing to weight gain. A change in the proportion of Bacteroidetes and Firmicutes may determine host’s risk of obesity, lack of sufficient sleep has been suggested as a cause for weight gain or the difficulty in maintaining a healthy weight. As a result, sleep deprivation over time may contribute to increased caloric intake and decreased self-control over food cravings, weight gain is a common side-effect of certain psychiatric medications
5. Human development (biology) – Human development is the process of growing to maturity. In biological terms, this entails growth from a zygote to an adult human being. Fertilization occurs when the sperm enters the ovums membrane. The genetical material of the sperm and egg that combine to form a cell, called a zygote. The germinal stage refers to the time from fertilization, through the development of the early embryo, the germinal stage is over at about 10 days of gestation. The zygote contains a full complement of genetic material and develops into the embryo, briefly, embryonic developments have four stages, the morula stage, the bastula stage, the gastrula stage, and the neurula stage. Prior to implantation, the remains in a protein shell, the zona pellucida. A week after fertilization the embryo still has not grown in size and this induces a decidual reaction, wherein the uterine cells proliferate and surround the embryo thus causing it to become embedded within the uterine tissue. The embryo, meanwhile, proliferates and develops both into embryonic and extra-embryonic tissue, the forming the fetal membranes and the placenta. In humans, the embryo is referred to as a fetus in the stages of prenatal development. The transition from embryo to fetus is arbitrarily defined as occurring 8 weeks after fertilization, in comparison to the embryo, the fetus has more recognizable external features and a set of progressively developing internal organs. A nearly identical process occurs in other species, auxology Child development Developmental biology Embryogenesis Life-history theory
6. Benedict's reagent – Benedicts reagent is a chemical reagent named after an American chemist, Stanley Rossiter Benedict. Benedicts reagent is a chemical reagent commonly used to detect the presence of reducing sugars and this includes all monosaccharides and many disaccharides, including lactose and maltose. Such tests that use this reagent are called the Benedicts tests, generally, Benedicts test detects the presence of aldehydes, alpha-hydroxy-ketones, also by hemiacetal, including those that occur in certain ketoses. A positive test with Benedicts reagent is shown by a change from clear blue to a brick-red precipitate. One litre of Benedicts reagent can be prepared from 100 g of sodium carbonate,173 g of sodium citrate and 17.3 g of copper sulfate pentahydrate. It is often used in place of Fehlings solution, the principle of Benedicts test is that when reducing sugars are heated in the presence of an alkali they get converted to powerful reducing species known as enediols. Enediols reduce the cupric compounds present in the Benedicts reagent to cuprous compounds which get precipitated as insoluble red copper oxide, the color of the obtained precipitate gives an idea about the quantity of sugar present in the solution, hence the test is semi-quantitative. A greenish precipitate indicates about 0.5 g% concentration, yellow precipitate indicates 1 g% concentration, orange indicates 1.5 g% and red indicates 2 g% or higher concentration. To test for the presence of monosaccharides and reducing sugars in food, the food sample is dissolved in water. During a water bath, which is usually 4–10 minutes, the solution should progress in the colors of blue, green, yellow, orange, red, a colour change would signify the presence of a reducing sugar. The common disaccharides lactose and maltose are directly detected by Benedicts reagent, because each contains a glucose with a free reducing aldehyde moiety, after isomerization. Sucrose contains two sugars joined by their glycosidic bond in such a way as to prevent the glucose isomerizing to aldehyde, sucrose is thus a non-reducing sugar which does not react with Benedicts reagent. Sucrose indirectly produces a result with Benedicts reagent if heated with dilute hydrochloric acid prior to the test. The acidic conditions and heat break the bond in sucrose through hydrolysis. The products of decomposition are glucose and fructose, both of which can be detected by Benedicts reagent, as described above. Starches do not react or react very poorly with Benedicts reagent, due to the small number of reducing sugar moieties. Inositol is another carbohydrate which produces a negative test, Benedicts reagent can be used to test for the presence of glucose in urine. Glucose in urine is called glucosuria and can be indicative of diabetes mellitus, false positive reaction can be due to the presence of other reducing substances in urine such as ascorbic acid, drugs and homogentisic acid
7. Trousseau sign of latent tetany – Trousseau sign of latent tetany is a medical sign observed in patients with low calcium. From 1 to 4 percent of patients will test positive for Trousseaus sign of latent tetany. This sign may be positive before other manifestations of such as hyperreflexia and tetany. To elicit the sign, a blood pressure cuff is placed around the arm and inflated to a greater than the systolic blood pressure. This will occlude the brachial artery, in the absence of blood flow, the patients hypocalcemia and subsequent neuromuscular irritability will induce spasm of the muscles of the hand and forearm. The wrist and metacarpophalangeal joints flex, the DIP and PIP joints extend, the sign is also known as main daccoucheur because it supposedly resembles the position of an obstetricians hand in delivering a baby. The sign is named after French physician Armand Trousseau who described the phenomenon in 1861 and it is distinct from the Trousseau sign of malignancy