Abnormal: Not normal. Deviating from the usual structure, position, condition, or behavior. In referring to a growth, abnormal may mean that it is cancerous or premalignant (likely to become cancer ). See the entire definition of Abnormal
Access: 1. In general, a means of approaching something. 2. In health care, the opportunity or right to receive health care. 3. In dialysis, the point on the body where a needle or catheter is inserted to gain entry to the bloodstream.
ADHD: Attention deficit hyperactivity disorder.
Aggressive: In oncology, quickly growing, tending to spread rapidly. As, for example, an aggressive tumor. See the entire definition of Aggressive
Alcohol: An organic chemical in which one or more hydroxyl (OH) groups are attached to carbon (C) atoms in place of hydrogen (H) atoms. Common alcohols include ethyl alcohol or ethanol (found in alcoholic beverages), methyl alcohol or methanol (can cause blindness) and propyl alcohol or propanol (used as a solvent and antiseptic ). Rubbing alcohol is a mixture of acetone , methyl isobutyl ketone, and ethyl alcohol. In everyday talk, alcohol usually refers to ethanol as, for example, in wine, beer, and liquor. It can cause changes in behavior and be addictive. See the entire definition of Alcohol
American Academy of Pediatrics: AAP. Its member pediatricians "dedicate their efforts and resources to the health, safety and well-being of infants, children, adolescents and young adults." According to the Academy, it had as of 1998 some 53,000 members in the United States, Canada and Latin America. Over 34,000 of them were board-certified and called Fellows of the American Academy of Pediatrics (FAAP). See the entire definition of American Academy of Pediatrics
American Psychiatric Association: A medical specialty society with over 35,000 US and international member physicians who "work together to ensure humane care and effective treatment for all persons with mental disorder, including mental retardation and substance-related disorders. It is the voice and conscience of modern psychiatry. Its vision is a society that has available, accessible quality psychiatric diagnosis and treatment." The American Psychiatric Association (APA) is the oldest national medical specialty society in the US.
Amniocentesis : Procedure used in prenatal diagnosis to obtain amniotic fluid which can be used for genetic and other diagnostic tests. Informally called an "amnio." See the entire definition of Amniocentesis
Amniotic fluid: The fluid bathing the fetus and serving as a shock absorber.
Angry: Pertaining to anger, an emotional state that may range in intensity from mild irritation to intense fury and rage. Anger has physical effects; it raises the heart rate and blood pressure and the levels of adrenaline and noradrenaline, and so on. See the entire definition of Angry
Anxiety: A feeling of apprehension and fear characterized by physical symptoms such as palpitations , sweating, and feelings of stress . Anxiety disorders are serious medical illnesses that affect approximately 19 million American adults. These disorders fill people's lives with overwhelming anxiety and fear. Unlike the relatively mild, brief anxiety caused by a stressful event such as a business presentation or a first date, anxiety disorders are chronic, relentless, and can grow progressively worse if not treated. See the entire definition of Anxiety
Atrophy: Wasting away or diminution. Muscle atrophy is wasting of muscle, decrease in muscle mass. See the entire definition of Atrophy
Attention: The ability to focus selectively on a selected stimulus, sustaining that focus and shifting it at will. The ability to concentrate. See the entire definition of Attention
Attention deficit hyperactivity disorder : A family of related chronic neurobiological disorders that interfere with an individual's capacity to: - regulate activity level (hyperactivity),
- inhibit behavior (impulsivity), and
- attend to tasks (inattention) in developmentally appropriate ways. The term "attention deficit hyperactivity disorder" is abbreviated and usually referred to as ADHD.
The core symptoms of ADHD include an inability to sustain attention and concentration, developmentally inappropriate levels of activity, distractibility, and impulsivity. See the entire definition of Attention deficit hyperactivity disorder
Autism : A spectrum of neuropsychiatric disorders characterized by deficits in social interaction and communication, and unusual and repetitive behavior. Some, but not all, people with autism are non-verbal. See the entire definition of Autism
Balance: A biological system that enables us to know where our bodies are in the environment and to maintain a desired position. Normal balance depends on information from the inner ear, other senses (such as sight and touch) and muscle movement. See the entire definition of Balance
Blood: The familiar red fluid in the body that contains white and red blood cells, platelets, proteins, and other elements. The blood is transported throughout the body by the circulatory system. Blood functions in two directions: arterial and venous. Arterial blood is the means by which oxygen and nutrients are transported to tissues while venous blood is the means by which carbon dioxide and metabolic by-products are transported to the lungs and kidneys, respectively, for removal from the body.
Brain: That part of the central nervous system that is located within the cranium ( skull ). The brain functions as the primary receiver, organizer and distributor of information for the body. It has two (right and left) halves called "hemispheres." See the entire definition of Brain
Cell: The basic structural and functional unit in people and all living things. Each cell is a small container of chemicals and water wrapped in a membrane . See the entire definition of Cell
Centers for Disease Control and Prevention: The US agency charged with tracking and investigating public health trends. The stated mission of the Centers for Disease Control and Prevention, commonly called the CDC, is "To promote health and quality of life by preventing and controlling disease, injury, and disability." See the entire definition of Centers for Disease Control and Prevention
Cheek: The side of the face forming the side wall of the mouth. See the entire definition of Cheek
Child health: Child health is the purview of pediatrics. See the entire definition of Child health
Chorionic villus sampling: A procedure for first-trimester prenatal diagnosis. Chorionic villus sampling may be done between the eighth and tenth weeks of pregnancy. The aim is to diagnose severe abnormalities afflicting the fetus. In the procedure, tissue is withdrawn from the villi (vascular fingers) of the chorion, a part of the placenta, and examined. Chorionic villus sampling is referred to commonly as CVS. See the entire definition of Chorionic villus sampling
Chromosome: A visible carrier of the genetic information. See the entire definition of Chromosome
Chromosomes: The microscopically visible carriers of the genetic material. They are composed of deoxyribonucleic acid (DNA) and proteins and, under a microscope, look like little rods. See the entire definition of Chromosomes
Clinical: 1. Having to do with the examination and treatment of patients. 2. Applicable to patients. A laboratory test may be of clinical value (of use to patients). See the entire definition of Clinical
Code: The genetic code is the correspondence between the triplet of bases in DNA with the amino acids. The discovery of the genetic code clearly ranks as one of the premiere events of what has been called the Golden Age of Biology (and Medicine). See the entire definition of Code
Cognitive: Pertaining to cognition , the process of knowing and, more precisely, the process of being aware, knowing, thinking, learning and judging. The study of cognition touches on the fields of psychology , linguistics, computer science, neuroscience , mathematics, ethology and philosophy. See the entire definition of Cognitive
Condition: The term "condition" has a number of biomedical meanings including the following: - An unhealthy state, such as in "this is a progressive condition."
- A state of fitness, such as "getting into condition."
- Something that is essential to the occurrence of something else; essentially a "precondition."
- As a verb: to cause a change in something so that a response that was previously associated with a certain stimulus becomes associated with another stimulus; to condition a person, as in behavioral conditioning.
Connective tissue: A material made up of fibers forming a framework and support structure for body tissues and organs. Connective tissue surrounds many organs. Cartilage and bone are specialized forms of connective tissue. All connective tissue is derived from mesoderm, the middle germ cell layer in the embryo.
Contrast: Short for "contrast media." Contrast media are X-ray dyes used to provide contrast, for example, between blood vessels and other tissue.
Cure: 1. To heal, to make well, to restore to good health. Cures are easy to claim and, all too often, difficult to confirm. 2. A time without recurrence of a disease so that the risk of recurrence is small, as in the 5-year cure rate for malignant melanoma . 3. Particularly in the past, a course of treatment. For example, take a cure at a spa. See the entire definition of Cure
Daughter: 1. A female offspring. 2. A female adopted child. 3. A product of radioactive decay. 4. A cell resulting from cell division.
Depression : An illness that involves the body, mood, and thoughts, that affects the way a person eats and sleeps, the way one feels about oneself, and the way one thinks about things. A depressive disorder is not the same as a passing blue mood. It is not a sign of personal weakness or a condition that can be wished away. People with a depressive disease cannot merely "pull themselves together" and get better. Without treatment, symptoms can last for weeks, months, or years. Appropriate treatment, however, can help most people with depression. See the entire definition of Depression
Developmental delay: Behind schedule in reaching milestones of early childhood development.
Diagnosis: 1 The nature of a disease ; the identification of an illness. 2 A conclusion or decision reached by diagnosis. The diagnosis is rabies . 3 The identification of any problem. The diagnosis was a plugged IV. See the entire definition of Diagnosis
Disease: Illness or sickness often characterized by typical patient problems (symptoms) and physical findings (signs). Disruption sequence: The events that occur when a fetus that is developing normally is subjected to a destructive agent such as the rubella (German measles) virus.
DNA: Deoxyribonucleic acid. One of two types of molecules that encode genetic information. (The other is RNA . In humans DNA is the genetic material; RNA is transcribed from it. In some other organisms, RNA is the genetic material and, in reverse fashion, the DNA is transcribed from it.) See the entire definition of DNA
Down syndrome : A common chromosome disorder due to an extra chromosome number 21 (trisomy 21). Down syndrome causes mental retardation, a characteristic face, and multiple malformations. Down syndrome is a relatively common birth defect. The chromosome abnormality affects both the physical and intellectual development of the individual. See the entire definition of Down syndrome
Ear: The hearing organ. There are three sections of the ear, according to the anatomy textbooks. They are the outer ear (the part we see along the sides of our head behind the temples), the middle ear, and the inner ear. But in terms of function, the ear has four parts: those three and the brain. Hearing thus involves all parts of the ear as well as the auditory cortex of the brain. The external ear helps concentrate the vibrations of air on the ear drum and make it vibrate. These vibrations are transmitted by a chain of little bones in the middle ear to the inner ear. There they stimulate the fibers of the auditory nerve to transmit impulses to the brain. See the entire definition of Ear
Elbow: The juncture of the long bones in the middle portion of the arm. The bone of the upper arm (humerus) meets both the ulna (the inner bone of the forearm) and radius (the outer bone of the forearm) to form a hinge joint at the elbow. The radius and ulna also meet one another in the elbow to permit a small amount of rotation of the forearm. The elbow therefore functions to move the arm like a hinge (forward and backward) and in rotation (outward and inward). The biceps muscle is the major muscle that flexes the elbow hinge, and the triceps muscle is the major muscle that extends it. The primary stability of the elbow is provided by the ulnar collateral ligament, located on the medial (inner) side of the elbow. The outer bony prominence of the elbow is the lateral epicondyle, a part of the humerus bone. Tendons attached to this area can be injured, causing inflammation or tendonitis (lateral epicondylitis, or tennis elbow). The inner portion of the elbow is a bony prominence called the medial epicondyle of the humerus. Additional tendons from muscles attach here and can be injured, likewise causing inflammation or tendonitis (medial epicondylitis, or golfer's elbow). See also: Elbow bursitis ; Elbow pain ; Nursemaid's elbow. See the entire definition of Elbow
Environment: The sum of the total of the elements, factors and conditions in the surroundings which may have an impact on the development , action or survival of an organism or group of organisms. See the entire definition of Environment
Enzyme: A protein (or protein-based molecule) that speeds up a chemical reaction in a living organism. An enzyme acts as catalyst for specific chemical reactions , converting a specific set of reactants (called substrates) into specific products. Without enzymes, life as we know it would not exist. See the entire definition of Enzyme
Eye: The organ of sight. The eye has a number of components. These components include but are not limited to the cornea, iris, pupil, lens, retina, macula, optic nerve, choroid and vitreous. See the entire definition of Eye
Family: 1. A group of individuals related by blood or marriage or by a feeling of closeness. 2. A biological classification of related plants or animals that is a division below the order and above the genus. 3. A group of genes related in structure and in function that descended from an ancestral gene. 4. A group of gene products similarly related in structure and function and of shared genetic descent. 5. Parents and their children. The most fundamental social group in humans.
Family history: The family structure and relationships within the family, including information about diseases in family members. See the entire definition of Family history
Father: (1) The male parent. (2) One who originates. For example, "Wilhelm Roentgen is considered the father of radiology." (3) To produce offspring as a male. (4) To provide paternal protection and guidance to children.
FDA: The Food and Drug Administration, an agency within the U.S. Public Health Service, which is a part of the Department of Health and Human Services. See the entire definition of FDA
Feet: The plural of foot, both an anatomic structure and a unit of measure. See the entire definition of Feet
Female: The traditional definition of female was "an individual of the sex that bears young" or "that produces ova or eggs". However, things are not so simple today. Female can be defined by physical appearance, by chromosome constitution (see Female chromosome complement), or by gender identification. Female chromosome complement: The large majority of females have a 46, XX chromosome complement (46 chromosomes including two X chromosomes). A minority of females have other chromosome constitutions such as 45,X (45 chromosomes including only one X chromosome) and 47,XXX (47 chromosomes including three X chromosomes).
Fertilization: Fertilization is the process of combining the male gamete, or "sperm," with the female gamete, or "ovum." The product of this combination is a cell called a zygote.
Flat feet: A condition of the feet in which the arch of the instep is flattened and the entire sole touches the ground. See the entire definition of Flat feet
FMR1: The gene responsible for the production of a protein called FMRP. Lack of FMRP results in the fragile X syndrome. (FMRP is an acronym composed of the first letters of Familial Mental Retardation Protein).
FMRP: As stated in the entry for FMR1, FMRP is an acronym composed of the first letters of Familial Mental Retardation Protein.
Folic acid: One of the B vitamins that is a key factor in the synthesis (the making) of nucleic acid (DNA and RNA). See the entire definition of Folic acid
Food and Drug Administration: The FDA, an agency within the U.S. Public Health Service, which is a part of the Department of Health and Human Services. See the entire definition of Food and Drug Administration
Fragile X syndrome: One of the most common causes of inherited mental retardation and neuropsychiatric disease in human beings, affects as many as one in 2000 males and one in 4000 females. The syndrome is also known as FRAXA (the fragile X chromosome itself) and as the Martin-Bell syndrome. However, the preferred name is fragile X syndrome. See the entire definition of Fragile X syndrome
Gene: The basic biological unit of heredity . A segment of deoxyribonucleic acid (DNA) needed to contribute to a function. See the entire definition of Gene
Generic: 1. The chemical name of a drug. 2. A term referring to the chemical makeup of a drug rather than to the advertised brand name under which the drug may be sold. 3.A term referring to any drug marketed under its chemical name without advertising. See the entire definition of Generic
Genes: The basic biological units of heredity . Segments of deoxyribonucleic acid (DNA) needed to contribute to a function. See the entire definition of Genes
Genetic: Having to do with genes and genetic information.
Genetic code: The instructions in a gene that tell the cell how to make a specific protein. A, T, G, and C are the "letters" of the DNA code. They stand for the chemicals adenine, thymine, guanine, and cytosine, respectively, that make up the nucleotide bases of DNA. Each gene's code combines the four chemicals in various ways to spell out 3-letter "words" that specify which amino acid is needed at every step in making a protein. See the entire definition of Genetic code
Genetic screening: Testing a population to identify individuals at risk for a genetic disease or for transmitting it. Newborns may be screened for PKU (phenylketonuria), Jews for the gene for Tay-Sachs disease, Blacks for the sickle cell gene, etc.
Genetic testing: Tests done for clinical genetic purposes. Genetic tests may be done for diverse purposes pertaining to clinical genetics, including the diagnosis of genetic disease in children and adults; the identification of future disease risks; the prediction of drug responses; and the detection of risks of disease to future children. See the entire definition of Genetic testing
Genetics: The scientific study of heredity . Genetics pertains to humans and all other organisms. So, for example, there is human genetics, mouse genetics, fruitfly genetics, etc. See the entire definition of Genetics
Genome: All of the genetic information, the entire genetic complement, all of the hereditary material possessed by an organism. See the entire definition of Genome
Guanine: One of the four bases in DNA that make up the letters ATGC. Guanine is the "G". The others are adenine, cytosine, and thymine. Guanine always pairs with cytosine to form the base pair G-C (guanine-cytosine) in the DNA. The other base pair in the DNA is A-T (adenine-thymine). Each base pair forms a rung in the DNA ladder. Guanine is also one of the four bases in RNA.
Health: As officially defined by the World Health Organization, a state of complete physical, mental, and social well-being, not merely the absence of disease or infirmity.
Heart: The muscle that pumps blood received from veins into arteries throughout the body. It is positioned in the chest behind the sternum (breastbone; in front of the trachea, esophagus, and aorta; and above the diaphragm muscle that separates the chest and abdominal cavities. The normal heart is about the size of a closed fist, and weighs about 10.5 ounces. It is cone-shaped, with the point of the cone pointing down to the left. Two-thirds of the heart lies in the left side of the chest with the balance in the right chest. See the entire definition of Heart
Heart murmur: An unusual heart sound which may be innocent or reflect disease.
Heart rate: The number of heart beats per unit time, usually per minute. The heart rate is based on the number of contractions of the ventricles (the lower chambers of the heart). The heart rate may be too fast ( tachycardia ) or too slow ( bradycardia ). The pulse is bulge of an artery from the wave of blood coursing through the blood vessel as a result of the heart beat. The pulse is often taken at the wrist to estimate the heart rate. See the entire definition of Heart rate
Hernia: A general term referring to a protrusion of a tissue through the wall of the cavity in which it is normally contained. See the entire definition of Hernia
Hormone: A chemical substance produced in the body that controls and regulates the activity of certain cells or organs. See the entire definition of Hormone
Human genome: All of the DNA that a person possesses. The human genome is made up of all of the DNA in our chromosomes as well as that in our mitochondria . (Each of us has, in fact, two genomes -- a large chromosomal genome and a much smaller mitochondrial genome .) Our genome also includes every gene we own plus all of our junk DNA The human genome is both "the treasury of human inheritance" and a vast dump (or recycling center). See the entire definition of Human genome
Hyperactivity: A higher than normal level of activity. An organ can be described as hyperactive if it is more active than usual. Behavior can also be hyperactive. See the entire definition of Hyperactivity
Idiopathic: Of unknown cause. Any disease that is of uncertain or unknown origin may be termed idiopathic. For example, acute idiopathic polyneuritis , diffuse idiopathic skeletal hyperostosis , idiopathic pulmonary fibrosis , idiopathic scoliosis , etc. See the entire definition of Idiopathic
Intelligence quotient: An attempt to measure the intelligence of someone. Abbreviated IQ. The IQ score is usually based upon the results of a written test. To calculate the IQ, the person's mental age as determined by a test is divided by chronologic age, and the result is multiplied by 100. See the entire definition of Intelligence quotient
Intelligence test: A questionnaire or series of exercises designed to measure intelligence. It is generally understood that intelligence tests are less a measure of innate ability to learn as of what the person tested has already learned. There are many types of intelligence tests, and they may measure learning and/or ability in a wide variety of areas and skills. Scores may be presented as an IQ (intelligence quotient), a mental age, or on a scale.
Intervention: The act of intervening, interfering or interceding with the intent of modifying the outcome. In medicine, an intervention is usually undertaken to help treat or cure a condition. For example, early intervention may help children with autism to speak. "Acupuncture as a therapeutic intervention is widely practiced in the United States," according to the National Institutes of Health. From the Latin intervenire, to come between.
James Watson: See: Watson, James.
Jaw: The bones below the mouth (the mandible) and the bone above the mouth just above the mouth (the maxilla). The word jaw comes from the Anglo-Saxon ceowan meaning to chew. See the entire definition of Jaw
Knee: The knee is a joint which has three parts. The thigh bone (the femur) meets the large shin bone (the tibia) to form the main knee joint. This joint has an inner (medial) and an outer (lateral) compartment. The kneecap (the patella) joins the femur to form a third joint, called the patellofemoral joint. The patella protects the front of the knee joint. See the entire definition of Knee
Laboratory: A place for doing tests and research procedures and preparing chemicals, etc. Although "laboratory" looks very like the Latin "laboratorium" (a place to labor, a work place), the word "laboratory" came from the Latin "elaborare" (to work out, as a problem, and with great pains), as evidenced by the Old English spelling "elaboratory" designating "a place where learned effort was applied to the solution of scientific problems." See the entire definition of Laboratory
Learning disability : A childhood disorder characterized by difficulty with certain skills such as reading or writing in individuals with normal intelligence. Learning disorders affect the ability to interpret what one sees and hears or the ability to link information from different parts of the brain . These limitations can show up in many ways -- as specific difficulties with spoken and written language, coordination, self-control, or attention. Such difficulties extend to schoolwork and can impede learning to read or write, or to do math. See the entire definition of Learning disability
Lithium : Lithium carbonate (brand names: Eskalith; Lithobid), a drug used as a mood stabilizer for the treatment of manic/depressive (bipolar) disorder . It prevents or diminishes the intensity of episodes of mania in bipolar patients. Typical symptoms of mania include pressure of speech, motor hyperactivity, reduced need for sleep , flight of ideas, grandiosity, elation, poor judgment, aggressiveness and possibly hostility. See the entire definition of Lithium
Male: The traditional definition of male was "an individual of the sex that produces sperm" (or some such). However, things are not so simple today. Male can be defined by physical appearance, by chromosome constitution (see Male chromosome complement), or by gender identification.
Massage: The manipulation of muscle and connective tissue to enhance the function of those tissues and promote relaxation and well-being. Therapeutic massage can ease tension and reduce pain. Massage can be a part of physical therapy or practiced on its own. It can also be highly effective for reducing the symptoms of arthritis, back pain, carpal tunnel syndrome, and other disorders of the muscles and/or nervous system.
Medication: 1. A drug or medicine. 2. The administration of a drug or medicine. (Note that "medication" does not have the dangerous double meaning of "drug.")
Melatonin: A hormone produced by the pineal gland, melatonin is intimately involved in regulating the sleeping and waking cycles, among other processes. Melatonin supplements are sometimes used by people who have chronic insomnia. Always see your doctor before taking melatonin, as it is not recommended for all patients with sleep problems.
Menopause : The time in a woman's life when menstrual periods permanently stop; it is also called the "change of life." Menopause is the opposite of the menarche. See the entire definition of Menopause
Mental retardation: A term used when a person has certain limitations in mental functioning and in skills such as communicating, taking care of him or herself, and social skills. These limitations will cause a child to learn and develop more slowly than a typical child. Children with mental retardation may take longer to learn to speak, walk, and take care of their personal needs such as dressing or eating. They are likely to have trouble learning in school. They will learn, but it will take them longer. There may be some things they cannot learn. As many as 3 out of every 100 people have mental retardation. In fact, 1 out of every 10 children who need special education has some form of mental retardation. See the entire definition of Mental retardation
Messenger RNA: The key intermediary in gene expression, translating the DNA's genetic code into the amino acids that make up proteins. Messenger RNA is abbreviated mRNA.
Methylation: 1. In chemistry, the addition of a methyl group to a molecule. 2. On a protein level, the addition of a methyl group or groups to the amino acid arginine or lysine in a protein. 3. On a DNA level, the addition of a methyl group to a cytosine residue to convert it to 5-methylcytosine. Methylation of DNA occurs at CpG sites, where cytosine (C) lies next to guanine (G). The CpG sites are in regions near the promoters of a genes. These regions are known as CpG islands. The state of methylation of CpG islands is critical to both gene activity and gene expression.
Microscope: An optical instrument that augments the power of the eye to see small objects. The name microscope was coined by Johannes Faber (1574-1629) who in 1628 borrowed from the Greek to combined micro-, small with skopein, to view. Although the first microscopes were simple microscopes, most (if not all) optical microscopes today are compound microscopes.
Middle ear: There are three sections of the ear. They are the external ear, the middle ear, and the inner ear. The middle ear consists of the ear drum (the tympanum or tympanic membrane) and, beyond it, a cavity. This cavity is connected via a canal (the Eustachian tube) to the pharynx (the nasopharynx). The Eustachian tube permits the gas pressure in the middle ear cavity to adjust to external air pressure (so, as you're descending in a plane, it's the Eustachian tube that opens when your ears "open"). The middle ear cavity also contains a chain of 3 little bones (ossicles) that connect the ear drum to the internal ear. The ossicles are named (not the Nina, the Pinta and the Santa Maria, but) the malleus, incus, and stapes. In terms of function, the middle ear communicates with the pharynx, equilibrates with external pressure and transmits the ear drum vibrations to the inner ear. See the entire definition of Middle ear
Mind: That which thinks, reasons, perceives, wills, and feels. The mind now appears in no way separate from the brain. In neuroscience, there is no duality between the mind and body. They are one.
Mitral valve: A valve in the heart situated between the left atrium and the left ventricle that permits blood to flow from the left atrium into the left ventricle but not in the reverse direction. See the entire definition of Mitral valve
Mitral valve prolapse : Drooping down or abnormal bulging of the mitral valve's cusps backward into the atrium during the contraction of the heart. Mitral valve prolapse is often an asymptomatic condition but it may be marked by mitral regurgitation with symptoms (as chest pain, fatigue, dizziness, dyspnea, or palpitations) with a tendency in some cases to endocarditis or ventricular tachycardia. See the entire definition of Mitral valve prolapse
Molecule: The smallest unit of a substance that can exist alone and retain the character of that substance.
Mosaic: An individual or tissue containing two or more types of genetically different cells. All females are mosaics because of X-chromosome inactivation (lyonization). See the entire definition of Mosaic
Mother: (1) The female parent. (2) To produce offspring as a female. To attribute the maternity of. (3) A cell or other structure from which similar cells or structures are formed. Accordingly, such a cell might be referred to as the mother cell.(4) To provide maternal protection, guidance, and nurturing to children. See the entire definition of Mother
Motor: In medicine, having to do with the movement of a part of the body. Something that produces motion or refers to motion. For example, a motor neuron is a nerve cell that conveys an impulse to a muscle causing it to contract. The term "motor" today is also applied to a nerve that signals a gland to secrete. Motor is as opposed to sensory.
Murmur: A sound due to vibrations from the flow of blood through the heart or great vessels. A murmur may be innocent and be of no significance. Or it may be pathologic and reflect disease. A murmur is usually heard with a stethoscope.
Mutation: A permanent change, a structural alteration, in the DNA or RNA . In humans and many other organisms, mutations occur in DNA. However, in retroviruses like HIV , mutations occur in RNA which is the genetic material of retroviruses. See the entire definition of Mutation
Neural: Having to do with nerve cells. See the entire definition of Neural
Neurology: The medical specialty concerned with the diagnosis and treatment of disorders of the nervous system -- the brain, the spinal cord, and the nerves. See the entire definition of Neurology
NICHD: The National Institute of Child Health and Human Development, one of the US National Institutes of Health . NICHD is in a sense the NIH for kids in that it is concerned with child health . See the entire definition of NICHD
NIH: The National Institutes of Health. The NIH is an important U.S. health agency. It is devoted to medical research. Administratively under the Department of Health and Human Services (HHS), the NIH consists of 20-some separate Institutes and Centers. NIH's program activities are represented by these Institutes and Centers. See the entire definition of NIH
Nipple: The pigmented projection on the surface of the breast. Ducts that conduct milk from the mammary glands to the surface of the breast exit through the nipple. The surrounding flat area of pigmentation is the areola.
Normal range: By convention, the normal range for whatever (a particular test, condition, symptom, behavior, etc.) is set to cover ninety-five percent (95%) of all values from the general population. Five percent (5%) of results consequently fall outside the normal range. Values that prove normal can therefore sometimes be outside the normal range. See the entire definition of Normal range
Nucleus: 1) In cell biology, the structure that houses the chromosomes. 2) In neuroanatomy, a group of nerve cells.
Obsessive-compulsive disorder: A psychiatric disorder characterized by obsessive thoughts and compulsive actions, such as cleaning, checking, counting, or hoarding. Obsessive-compulsive disorder (OCD), one of the anxiety disorders, is a potentially disabling condition that can persist throughout a person's life. The individual who suffers from OCD becomes trapped in a pattern of repetitive thoughts and behaviors that are senseless and distressing but extremely difficult to overcome. OCD occurs in a spectrum from mild to severe, but if severe and left untreated, can destroy a person's capacity to function at work, at school, or even in the home. See the entire definition of Obsessive-compulsive disorder
Occupational therapist: A licensed health professional who is trained to evaluate patients with joint conditions, such as arthritis , to determine the impact the disease on their activities of daily living. Occupational therapists can design and prescribe assistive devices that can improve the quality of the activities of daily living for patients with arthritis and other conditions of the muscles and joints. See the entire definition of Occupational therapist
Ovarian: Of or pertaining to the ovary.
Parkinsonism: 1. Parkinson disease. 2. A syndrome similar to Parkinson disease, for example, as a side effect of an antipsychotic drug.
Pediatric: Pertaining to children.
Pediatrics: "Pediatrics is concerned with the health of infants, children and adolescents, their growth and development, and their opportunity to achieve full potential as adults." (Richard E.Behrman in Nelson's Textbook of Pediatrics) See the entire definition of Pediatrics
Phenotype: The appearance of an individual, which results from the interaction of the person's genetic makeup and his or her environment. By contrast, the genotype is merely the genetic constitution (genome) of an individual. For example, if a child's genotype includes the gene for osteogenesis imperfecta (brittle bone disease), minimal trauma can cause fractures. The gene is the genotype, and the brittle bones themselves are the phenotype.
Phenylketonuria : The inherited inability to metabolize (process) the essential amino acid phenylalanine due to complete or near-complete deficiency of the enzyme phenylalanine hydroxylase. See the entire definition of Phenylketonuria
Physical therapist: A person trained and certified by a state or accrediting body to design and implement physical therapy programs. Physical therapists may work within a hospital or clinic, in a school providing assistance to special education students, or as an independent practitioner.
Physical therapy: A branch of rehabilitative health that uses specially designed exercises and equipment to help patients regain or improve their physical abilities. Physical therapists work with many types of patients, from infants born with musculoskeletal birth defects, to adults suffering from sciatica or the after- effects of injury, to elderly post-stroke patients.
Physiology: The study of how living organisms function including such processes as nutrition, movement, and reproduction. See the entire definition of Physiology
Pill: In pharmacy, a medicinal substance in a small round or oval mass meant to be swallowed. Pills often contain a filler and a plastic substance such as lactose that permits the pill to be rolled by hand or machine into the desired form. The pill may then be coated with a varnishlike substance. See the entire definition of Pill
PKU: Short for phenylketonuria. See: Phenylketonuria.
Placenta: A temporary organ joining the mother and fetus, the placenta transfers oxygen and nutrients from the mother to the fetus, and permits the release of carbon dioxide and waste products from the fetus. It is roughly disk-shaped, and at full term measures about seven inches in diameter and a bit less than two inches thick. The upper surface of the placenta is smooth, while the under surface is rough. The placenta is rich in blood vessels. See the entire definition of Placenta
Posture: The carriage of the body as a whole, the attitude of the body, or the position of the limbs (the arms and legs). See the entire definition of Posture
Predispose: To make more likely or render susceptible. Smoking predisposes to a number of diseases, including esophageal cancer.
Pregnancy: The state of carrying a developing embryo or fetus within the female body. This condition can be indicated by positive results on an over-the-counter urine test, and confirmed through a blood test, ultrasound, detection of fetal heartbeat, or an X-ray. Pregnancy lasts for about nine months, measured from the date of the woman's last menstrual period (LMP). It is conventionally divided into three trimesters, each roughly three months long. See the entire definition of Pregnancy
Pregnant: The state of carrying a developing fetus within the body. See the entire definition of Pregnant
Prenatal: Occurring or existing before birth. See the entire definition of Prenatal
Prevalence: The proportion of individuals in a population having a disease. Prevalence is a statistical concept referring to the number of cases of a disease that are present in a particular population at a given time. See the entire definition of Prevalence
Promoter: In molecular biology, a site on DNA to which the enzyme RNA polymerase can bind and initiate the transcription of DNA into RNA.
Protein: A large molecule composed of one or more chains of amino acids in a specific order determined by the base sequence of nucleotides in the DNA coding for the protein. See the entire definition of Protein
Proteins: Large molecules composed of one or more chains of amino acids in a specific order determined by the base sequence of nucleotides in the DNA coding for the protein. See the entire definition of Proteins
Psychiatric: Pertaining to or within the purview of psychiatry , the medical specialty concerned with the prevention, diagnosis , and treatment of mental illness. See the entire definition of Psychiatric
Puberty: A complex biologic and psychologic process involving sexual development, accelerated growth, and adrenal maturation heralded by the secretion of gonadotropin releasing hormone (GnRH) from a part of the brain called the hypothalamus . This event is the first known step in the reproductive cascade. It initiates the pulsatile release of gonadotropins , gonadal secretion of sex steroids, pubertal development, and gametogenesis (the production of sperm and ova ). See the entire definition of Puberty
Quotient: The result of mathematical division. The I.Q. (Intelligence Quotient) is arrived at by dividing the person's mental age (as determined on the Binet test) by the person's chronologic age and multiplying by 100. So if a child scores at the 8-year old level but is only 6, the I.Q. is 8/6 X 100=125.
Range: In medicine and statistics, the difference between the lowest and highest numerical values. For example, if five premature infants are born weighing two, three, four, four, and five pounds respectively, the range of their birth weights is two to five pounds.
Risk factor: Something that increases a person's chances of developing a disease.
RNA: Short for ribonucleic acid, a nucleic acid molecule similar to DNA but containing ribose rather than deoxyribose. RNA is formed upon a DNA template. There are several classes of RNA molecules. See the entire definition of RNA
Section: 1) In anatomy, a slice of tissue. A biopsy obtained by surgery is usually sectioned (sliced), and these sections are inspected under a microscope. 2) In obstetrics, short for Caesarian section. 3) In surgery, the division of tissue during an operation.
Sensation: In medicine and physiology , sensation refers to the registration of an incoming ( afferent ) nerve impulse in that part of the brain called the sensorium , which is capable of such perception. Therefore, the awareness of a stimulus as a result of its perception by sensory receptors. (Sensory is here synonymous with sensation.) See the entire definition of Sensation
Sense: In biology and medicine, the faculty of sensory reception. The ability to convey specific types of external or internal stimuli to the brain and perceive them. Sensory reception occurs through a process known as transduction in which stimuli are converted into nerve impulses which are relayed to the brain. See the entire definition of Sense
Sensitivity: 1. In psychology, the quality of being sensitive. As, for example, sensitivity training, training in small groups to develop a sensitive awareness and understanding of oneself and of ones relationships with others. 2. In disease epidemiology, the ability of a system to detect epidemics and other changes in disease occurrence. 3. In screening for a disease, the proportion of persons with the disease who are correctly identified by a screening test. 4. In the definition of a disease, the proportion of persons with the disease who are correctly identified by defined criteria.
Sensory: Relating to sensation , to the perception of a stimulus and the voyage made by incoming ( afferent ) nerve impulses from the sense organs to the nerve centers. See the entire definition of Sensory
Sign: Any objective evidence of disease. Gross blood in the stool is a sign of disease. It can be recognized by the patient, doctor, nurse, or others. In contrast, a symptom is, by its nature, subjective. Abdominal pain is a symptom. It is something only the patient can know. See the entire definition of Sign
Sign language: A language that employs signs made with the hands and other movements, including facial expressions and postures of the body, used primarily by people who are deaf. There are many different sign languages as, for example, British and American sign languages. British sign language (BSL) is not easily intelligible to users of American sign language (ASL). Unlike ASL, BSL uses a two-handed alphabet. In developing countries, deaf people may use the sign language of educators and missionaries from elsewhere in the world. For example, some deaf individuals in Madagascar use Norwegian sign language. By contrast, deaf children in Nicaragua have created their own sign language. Study of the emerging Nicaruagan sign language (NSL) has revealed that children naturally possess learning abilities capable of giving language its fundamental structure. See also: American sign language . See the entire definition of Sign language
Silver: A metal used in some medications and in many "natural" remedies, as well as in silver amalgam for filling cavities in teeth. Silver has antibiotic properties. However, overuse of silver, or use of products containing silver by people with certain health conditions, can result in silver poisoning (argyria). See the entire definition of Silver
Skin: The skin is the body's outer covering. It protects us against heat and light, injury, and infection. It regulates body temperature and stores water, fat, and vitamin D. Weighing about 6 pounds, the skin is the body's largest organ. It is made up of two main layers; the outer epidermis and the inner dermis. See the entire definition of Skin
Sleep : The body's rest cycle. See the entire definition of Sleep
Southern blot: A test commonly used in molecular biology and genetics, the purpose of the test being to check for a match between DNA molecules. See the entire definition of Southern blot
Sperm: A sperm is the male "gamete" or sex cell. It combines with the female "gamete," called an ovum, to form a zygote. The formation process is called "fertilization." (see ovum, zygote).
Substance: 1. Material with particular features, as a pressor substance. 2. The material that makes up an organ or structure. Also known in medicine as the substantia. 3. A psychoactive drug as, for example, in substance abuse.
Syndrome: A set of signs and symptoms that tend to occur together and which reflect the presence of a particular disease or an increased chance of developing a particular disease. See the entire definition of Syndrome
Testicles: The testicles (also called testes or gonads) are the male sex glands. They are located behind the penis in a pouch of skin called the scrotum. The testicles produce and store sperm, and they are also the body's main source of male hormones (testosterone). These hormones control the development of the reproductive organs and other male characteristics, such as body and facial hair, low voice, and wide shoulders.
Therapeutic: Relating to therapeutics , that part of medicine concerned specifically with the treatment of disease . The therapeutic dose of a drug is the amount needed to treat a disease. See the entire definition of Therapeutic
Therapy: The treatment of disease . See the entire definition of Therapy
Thumb: The short thick finger situated at an angle to the other fingers so it can be opposed to the them, making it possible to pick up and hold things. The thumb is analogous in position to the big toe (the great toe) and similarly has only two phalanges (all the other digits have three).
Tissue: A tissue in medicine is not like a piece of tissue paper. It is a broad term that is applied to any group of cells that perform specific functions. A tissue in medicine need not form a layer. Thus, - The bone marrow is a tissue;
- Connective tissue consists of cells that make up fibers in the framework supporting other body tissues; and
- Lymphoid tissue is the part of the body's immune system that helps protect it from bacteria and other foreign entities.
Transgenic: Having genetic material ( DNA ) from another species. This term can be applied to an organism that has genes from another organism. It is understood that the foreign genes are in the transgenic animal's germ-cell DNA and so can be transmitted from one generation to the next. See the entire definition of Transgenic
Tremor: Any abnormal repetitive shaking movement of the body. Tremors have many causes and can be inherited, be related to illnesses such as thyroid disease, or caused by fever, hypothermia, drugs or fear.
Villus: 1. A tiny finger-like or hair-like projection. 2. A small vascular protrusion. Villus is the Latin word for shaggy hair or fleece. The plural is villi. See the entire definition of Villus
Watson: See: Watson, James.
X chromosome: A sex chromosome found in both females and males. Normal females usually have two X chromosomes. Normal males usually have one X along with a Y chromosome . The complete chromosome complement consisting of 46 chromosomes is conventionally written as 46,XX for females and 46,XY for males. See the entire definition of X chromosome
Y chromosome: The sex chromosome found together with an X chromosome in most normal males. Once thought to be a genetic wasteland, the Y now is known to contain at least 20 genes, some of them unique to the Y including the male-determining gene and male fitness genes that are active only in the testis and are thought responsible for the formation of sperm. Other genes on the Y have counterparts on the X chromosome, are active in many body tissues and play crucial "housekeeping" roles with the cell. See the entire definition of Y chromosome
- Amniocentesis - Learn about amniocentesis, a procedure that examines the chromosomes of the fetus to determine lung maturity, and the possiblities of birth defects.
- Learning Disabilities - Read about learning disabilities, like the skills affected such as reading, writing, listening, speaking, reasoning, and mathematics. Causes, symptoms, diagnosis, and treatment information is included.
- Premature Ovarian Failure (POF) - Learn about premature ovarian failure (POF) - (the normal functioning of ovaries in women under 40 stop). Some causes of POF include follicle depletion or dysfunction.
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