Solitary Pulmonary Nodule Glossary of Medical Terms

These are medical definitions of medical terms from the MedTerms.com medical dictionary that appear in the Solitary Pulmonary Nodule article.

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 ).
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Abscess: A local accumulation of pus anywhere in the body. The following are some examples of abscesses:

  1. A skin abscess is better known as a common boil;
  2. A peritonsillar abscess is a persistent collection of pus behind the tonsils ; and
  3. A perianal abscess is a pool of pus that forms next to the anus , often causing considerable tenderness and swelling in that area and pain on sitting down and on defecating.

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Absorb: 1. To take something in, as through the skin or the intestine.
2. To react with radiation and reduce it in intensity, as with a dose of radiation or transmitted light.
See also: Absorbed dose ; Absorption ; Malabsorption ; Reabsorption .
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Airway: The path air follows to get into and out of the lungs. The mouth and nose are the normal entry and exit ports. Entering air then passes through the back of the throat (pharynx), continues through the voice box (larynx), down the trachea, and finally out the branching tubes known as bronchi.
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Alkaline phosphatase: An enzyme made in the liver , bone, and the placenta and normally present in high concentrations in growing bone and in bile. Alkaline phosphatase is released into the blood during injury and during such normal activities as bone growth and pregnancy . It is measured in a routine blood test.
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American Medical Association (AMA): The AMA. The AMA's mission statement proclaims:
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Anemia: The condition of having less than the normal number of red blood cells or less than the normal quantity of hemoglobin in the blood. The oxygen-carrying capacity of the blood is, therefore, decreased.
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Antigen: A substance that is capable of causing the production of an antibody .
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Arteriovenous malformation (AVM): An arteriovenous malformation (AVM) is a congenital disorder (one present at birth) of blood vessels in the brain , brainstem , or spinal cord that is characterized by a complex, tangled web of abnormal arteries and veins connected by one or more fistulas (abnormal communications).
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Arthritis: Inflammation of a joint. When joints are inflamed they can develop stiffness, warmth, swelling, redness and pain. There are over 100 types of arthritis . (see osteoarthritis , rheumatoid arthritis , ankylosing spondylitis , psoriatic arthritis , lupus , gout , pseudogout ).
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Asbestos: A natural material made up of tiny fibers which can lodge in the lungs and lead to cancer or scarring of the lungs. The cancer may be lung cancer or ( mesothelioma ), which is a cancer of the lining of the lungs or other internal organs. The scarring of the lungs is termed asbestosis . Exposure to asbestos usually occurs by breathing contaminated air in workplaces that make or use asbestos or in the air of buildings containing asbestos that are being torn down or renovated.
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Aspiration: Removal of a sample of fluid and cells through a needle. Aspiration also refers to the accidental sucking in of food particles or fluids into the lungs.
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Atelectasis: Failure of full expansion of the lung at birth or a collapse thereafter of the lung. The word comes from the Greek "a-" (without) + "telos" (complete) + "rectasis" (expansion) = without complete expansion.
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Bacteria: Single-celled microorganisms which can exist either as independent (free-living) organisms or as parasites (dependent upon another organism for life).
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Benign: Not cancer. Not malignant . A benign tumor does not invade surrounding tissue or spread to other parts of the body. A benign tumor may grow but it stays put (in the same place).
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Biopsy: The removal of a sample of tissue for purposes of diagnosis. (Many definitions of "biopsy" stipulate that the sample of tissue is removed for examination under a microscope. This may or may not be the case. The diagnosis may be achieved by other means such as by analysis of chromosomes or genes.)
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Blastoma: A tumor thought to arise in embryonic tissue . The term "blastoma" is commonly used as part of the name for a tumor as, for examples, in glioblastoma and medulloblastoma (types of brain tumors), hepatoblastoma (a liver tumor), nephroblastoma ( Wilms tumor of the kidney), neuroblastoma (a childhood tumor of neural origin), osteoblastoma (a bone tumor) and retinoblastoma (a tumor of the retina ).
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Blastomycosis: Infection with a fungus called Blastomyces dermatitidis. The infection causes symptoms in about 50% of cases. It usually presents as a flu-like illness with fever, chills, productive cough, myalgia , arthralgia and pleuritic chest pain. Some patients fail to recover and develop chronic pulmonary infection or widespread disseminated infection (affecting the skin, bones, and genitourinary tract). It occasionally affects the meninges which cover the brain and spinal cord.
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Bronchi: The large air tubes leading from the trachea to the lungs that convey air to and from the lungs. The bronchi have cartilage as part of their supporting wall structure. The trachea divides to form the right and left main bronchi which, in turn, divide to form the lobar , segmental, and finally the subsegmental bronchi.
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Bronchoscope: A thin, flexible instrument used to view the air passages of the lung.
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Bronchoscopy : A procedure that permits the doctor to see the breathing passages through a lighted tube.
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Calcification: The process of building bone by suffusing tissues with calcium salts. Also called ossification.
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Calcium: A mineral found mainly in the hard part of bones, where it is stored. Calcium is added to bones by cells called osteoblasts and is removed from bones by cells called osteoclasts. Calcium is essential for healthy bones. It is also important for muscle contraction, heart action, nervous system maintenance, and normal blood clotting. Food sources of calcium include dairy foods, some leafy green vegetables such as broccoli and collards, canned salmon, clams, oysters, calcium-fortified foods, and tofu. According to the National Academy of Sciences, adequate intake of calcium is 1,200 milligrams a day (four glasses of milk) for men and women 51 and older, 1,000 milligrams a day for adults 19 through 50, and 1,300 milligrams a day for children 9 through 18. The upper limit for calcium intake is 2.5 grams daily. Learn more about Calcium with evidence-based information on RxList.

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Cancer: An abnormal growth of cells which tend to proliferate in an uncontrolled way and, in some cases, to metastasize (spread).
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Carcinoma: Cancer that begins in the skin or in tissues that line or cover body organs. For example, carcinoma can arise in the breast , colon, liver, lung, prostate, and stomach.
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Chest: The area of the body located between the neck and the abdomen . The chest contains the lungs , the heart and part of the aorta . The walls of the chest are supported by the dorsal vertebrae , the ribs , and the sternum .
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Chest X-ray: Commonly used to detect abnormalities in the lungs, but can also detect abnormalities in the heart, aorta, and the bones of the thoracic area. Metallic objects, such as jewelry are removed from the chest and neck areas for a chest x-ray to avoid interference with x-ray penetration and improve accuracy of the interpretation.
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Chloride: The major anion (negatively charged substance) in the blood and extracellular fluid (the body fluid that lies outside cells). Blood and other body fluids have almost the same concentration of chloride ion as sea water. The balance of chloride ion (Cl-) is closely regulated by the body.
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Colonic: 1. See: Colonic (adjective) . 2. See: Colonic (noun) .
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Computed tomography: An x-ray procedure that uses the help of a computer to produce a detailed picture of a cross section of the body. Also called a CT scan or CAT scan .
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Congenital: Present at birth. A condition that is congenital is one that is present at birth. There are numerous uses of "congenital" in medicine. There are, for example, congenital abnormalities. (For more examples, see below.)
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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 .
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Critical care: Intensive care. The specialized care of patients whose conditions are life-threatening and who require comprehensive care and constant monitoring, usually in intensive care units.
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CT scan: Computerized tomography scan. Pictures of structures within the body created by a computer that takes the data from multiple X-ray images and turns them into pictures on a screen. CT stands for computerized tomography.
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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.
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Cyst: A cyst is an abnormal, closed sac-like structure within a tissue that contains a liquid, gaseous, or semisolid substance. A cyst can occur anywhere in the body and can vary in size. The outer, or capsular, portion of a cyst is termed the cyst wall.
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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.
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Echinococcus: A tiny parasitic tapeworm. The larval stage of this tapeworm can cause human disease.
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Endemic: Present in a community at all times but in relatively low frequency. Something that is endemic is typically restricted or peculiar to a locality or region.
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Enzymes: Proteins that act as a catalysts in mediating and speeding a specific chemical reaction .
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Erythrocyte: A cell that contains hemoglobin and can carry oxygen to the body. Also called a red blood cell (RBC). The reddish color is due to the hemoglobin. Erythrocytes are biconcave in shape, which increases the cell's surface area and facilitates the diffusion of oxygen and carbon dioxide. This shape is maintained by a cytoskeleton composed of several proteins. Erythrocytes are very flexible and change shape when flowing through capillaries. Immature erythrocytes, called reticulocytes, normally account for 1-2 percent of red cells in the blood.
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Fibroma: A mass composed of fibrous tissue or connective tissue. Also called a fibroid tumor or fibroid.
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Fluoroscopy: An x-ray procedure that makes it possible to see internal organs in motion.
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Fungi: Plural of fungus .
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Glucose: The simple sugar (monosaccharide) that serves as the chief source of energy in the body. Glucose is the principal sugar the body makes. The body makes glucose from proteins, fats and, in largest part, carbohydrates. Glucose is carried to each cell through the bloodstream. Cells, however, cannot use glucose without the help of insulin . Glucose is also known as dextrose.
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Granuloma: A granuloma is one of a number of forms of localized nodular inflammation found in tissues. The fact that a granuloma is localized is important. So is its nodularity. Granulomas have a typical pattern when examined under a microscope.
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Hamartoma: A benign (noncancerous) tumor-like growth consisting of a disorganized mixture of cells and tissues normally found in the area of the body where the growth occurs.
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Hemoglobin: The oxygen-carrying pigment and predominant protein in the red blood cells . Hemoglobin forms an unstable, reversible bond with oxygen. In its oxygenated state it is called oxyhemoglobin and is bright red. In the reduced state it is called deoxyhemoglobin and is purple-blue.
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Histoplasmosis: A disease caused by the fungus Histoplasma capsulatum. Most people with histoplasmosis have no symptoms. However, histoplasma can cause acute or chronic lung disease and progressive disseminated histoplasmosis affecting a number of organs. It can be fatal if untreated.
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Hydrocarbon: An organic compound composed exclusively of hydrogen and carbon. All hydrocarbons have a carbon backbone with atoms of hydrogen attached to that backbone.
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Immune: Protected against infection. The Latin immunis means free, exempt.
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Immune system: A complex system that is responsible for distinguishing us from everything foreign to us, and for protecting us against infections and foreign substances. The immune system works to seek and kill invaders.
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Immunoglobulin: A protein produced by plasma cells and lymphocytes and characteristic of these types of cells. Immunoglobulins play an essential role in the body's immune system. They attach to foreign substances, such as bacteria, and assist in destroying them. Immunoglobulin is abbreviated Ig. The classes of immunoglobulins are termed immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin M (IgM), immunoglobulin D (IgD) and immunoglobulin E (IgE).
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Immunoglobulin G: Abbreviated IgG. A major class of immunoglobulins found in the blood, including many of the most common antibodies circulating in the blood. Also known as gamma globulin.
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Immunoglobulin M: Abbreviated IgM. A major class of immunoglobulins. IgM includes the antibodies that are usually produced first in an immune response and are later replaced by other types of antibodies.
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Incision: A cut. When making an incision, a surgeon is making a cut.
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Indicate: In medicine, to make a treatment or procedure advisable because of a particular condition or circumstance. For example, certain medications are indicated for the treatment of hypertension during pregnancy while others are contraindicated .
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Infarct: An area of tissue death due to a local lack of oxygen .
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Infection: The growth of a parasitic organism within the body. (A parasitic organism is one that lives on or in another organism and draws its nourishment therefrom.) A person with an infection has another organism (a "germ") growing within him, drawing its nourishment from the person.
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Inflammation: A basic way in which the body reacts to infection , irritation or other injury, the key feature being redness, warmth, swelling and pain . Inflammation is now recognized as a type of nonspecific immune response .
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Internal medicine: A medical specialty dedicated to the diagnosis and medical treatment of adults. A physician who specializes in internal medicine is referred to as an internist. A minimum of seven years of medical school and postgraduate training are focused on learning the prevention, diagnosis, and treatment of diseases of adults. Subspecialties of internal medicine include allergy and immunology, cardiology (heart), endocrinology (hormone disorders), hematology (blood disorders), infectious diseases, gastroenterology (diseases of the gut), nephrology (kidney diseases), oncology (cancer), pulmonology (lung disorders), and rheumatology ( arthritis and musculoskeletal disorders).
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Joint: A joint is the area where two bones are attached for the purpose of motion of body parts. A joint is usually formed of fibrous connective tissue and cartilage. An articulation or an arthrosis is the same as a joint.
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Lateral: 1. In anatomy, the side of the body or a body part that is farther from the middle or center of the body. Typically, lateral refers to the outer side of the body part, but it is also used to refer to the side of a body part. For example, when referring to the knee, lateral refers to the side of the knee farthest from the opposite knee. The opposite of lateral is medial .
2. In radiology, slang for a lateral X-ray .
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Lesion: Pronounced "lee-sion" with the emphasis on the "lee," a lesion can be almost any abnormality involving any tissue or organ due to any disease or any injury.
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Liver: An organ in the upper abdomen that aids in digestion and removes waste products and worn-out cells from the blood. The liver is the largest solid organ in the body. The liver weighs about three and a half pounds (1.6 kilograms). It measures about 8 inches (20 cm) horizontally (across) and 6.5 inches (17 cm) vertically (down) and is 4.5 inches (12 cm) thick.


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Lobe: Part of an organ that appears to be separate in some way from the rest. A lobe may be demarcated from the rest of the organ by a fissure (crack), sulcus (groove), connective tissue or simply by its shape. For example, there are the frontal, parietal, temporal, and occipital lobes of the brain.
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Lungs: The lungs are a pair of breathing organs located with the chest which remove carbon dioxide from and bring oxygen to the blood. There is a right and left lung.
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Lymph: An almost colorless fluid that travels through vessels called lymphatics in the lymphatic system and carries cells that help fight infection and disease.
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Lymphoid: Referring to lymphocytes, a type of white blood cell. Also refers to tissue in which lymphocytes develop.
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Lymphoid tissue: A part of the body's immune system that helps protect it from bacteria and other foreign entities.
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Lymphoma: Tumor of the lymphoid tissue. Diagnosis is by biopsy. Treatment may be chemotherapy , radiation, surgery, or medication, depending on the age of the patient and type of tumor.
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Malformation: A structural defect in the body due to abnormal embryonic or fetal development . There are many types of malformations. For example, cleft lip and cleft palate . See also Congenital malformation .
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Malignancy: A tumor that is malignant, that is cancerous, that can invade and destroy nearby tissue, and that may spread (metastasize) to other parts of the body.
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Malignant: 1. Tending to be severe and become progressively worse, as in malignant hypertension. 2. In regard to a tumor, having the properties of a malignancy that can invade and destroy nearby tissue and that may spread (metastasize) to other parts of the body.
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Medical school: A school with a curriculum leading to a medical degree. The mission of every medical school includes medical teaching, research, and patient care. All medical schools share the goal of preparing students in the art and science of medicine, and providing them with the background necessary to enter the period of graduate medical education. The years of medical school preceding graduate medical education are typically divided into a preclinical phase and a clinical phase.
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Membranous: Pertaining to a membrane . As in acute membranous gingivitis , membranous nephropathy , and pseudomembranous colitis .
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Metabolic: Relating to metabolism, the whole range of biochemical processes that occur within us (or any living organism). Metabolism consists of anabolism (the buildup of substances) and catabolism (the breakdown of substances).
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Metastasis: 1. The process by which cancer spreads from the place at which it first arose as a primary tumor to distant locations in the body.
2. The cancer resulting from the spread of the primary tumor. For example, someone with melanoma may have a metastasis in their brain. And a person with colon cancer may, fortunately, show no metastases.
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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.
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Mortality: A fatal outcome or, in one word, death. The word "mortality" is derived from "mortal" which came from the Latin "mors" (death). The opposite of mortality is, of course, immortality. Mortality is also quite distinct from morbidity (illness).
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Mouth: 1. The upper opening of the digestive tract, beginning with the lips and containing the teeth, gums, and tongue. Foodstuffs are broken down mechanically in the mouth by chewing and saliva is added as a lubricant. Saliva contains amylase, an enzyme that digests starch. 2. Any opening or aperture in the body. The mouth in both senses of the word is also called the os, the Latin word for an opening, or mouth. The o in os is pronounced as in hope. The genitive form of os is oris from which comes the word oral.
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Mucus: A thick slippery fluid produced by the membranes lining certain organs such as the nose, mouth, throat, and vagina. Mucus is the Latin word for "a semifluid, slimy discharge from the nose." Note that mucus is a noun while the adjective is mucous.
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Mycobacterium: A large family of bacteria that have unusually waxy cell walls that are resistant to digestion.
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Mycobacterium tuberculosis: The bacterium that causes tuberculosis. M. tuberculosis has unusually waxy walls, is slow-growing and among the most recalcitrant bacteria to treatment. The complete genome sequence of M. tuberculosis was published in 1998 revealing remarkably large proportion of its coding capacity devoted to producing enzymes involved in lipogenesis and lipolysis, the buildup and breakdown of lipids ( fats ). For more information, see: Tuberculosis .
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National Coalition for Cancer Survivorship: A survivor-led advocacy group that works on behalf of the millions of cancer survivors and the millions more touched by this disease. Founded in the US in 1986, NCCS issued the following 12 principles as Imperatives for Quality Cancer Care: Access, Advocacy, Action and Accountability:
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Neoplasm: A tumor. An abnormal growth of tissue. The word neoplasm is not synonymous with cancer . A neoplasm may be benign or malignant.
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Neoplastic: Pertaining to a neoplasm or neoplasia . See those terms for more information.See the entire definition of Neoplastic

Nerve: A bundle of fibers that uses chemical and electrical signals to transmit sensory and motor information from one body part to another. See: Nervous system .
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Nickel: A silver-white metallic element. Long-term exposure to nickel, such as from jewelry, can cause a form of contact dermatitis called nickel dermatitis. Exposure to nickel fumes can cause nasal cancer and lung cancer .
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Nocardiosis: An infection with bacteria called Nocardia which tend to strike the lungs, brain and skin, particularly in people with an impaired immune system. The majority (about 80%) of cases of nocardiosis involves lung infection, brain abscess , or disseminated (widespread) disease from Nocardia. The remaining 20% of cases are localized to the skin and cause cellulitis (skin infection).
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Nodule: A small solid collection of tissue, a nodule is palpable (can be felt). It may range in size from greater than 1.0 cm (3/8 inch) to somewhat less than 2 cm (13/16 inch) in diameter. A nodule may be present in the epidermis, dermis or subcutis (at any level in the skin).
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Nose: The external midline projection from the face.
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Oncology: The field of medicine devoted to cancer .
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Operation: Although there are many meanings to the word "operation", in medicine it refers to a surgical procedure.
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Organ: A relatively independent part of the body that carries out one or more special functions. The organs of the human body include the eye , ear , heart , lungs , and liver .
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Pain: An unpleasant sensation that can range from mild, localized discomfort to agony. Pain has both physical and emotional components. The physical part of pain results from nerve stimulation. Pain may be contained to a discrete area, as in an injury, or it can be more diffuse, as in disorders like fibromyalgia . Pain is mediated by specific nerve fibers that carry the pain impulses to the brain where their conscious appreciation may be modified by many factors.
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Periphery: 1. The outside or surface of a structure; the portion outside the central region.
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PET scan: The popular name (and abbreviation) of Positron Emission Tomography .
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Pharmacy: A location where prescription drugs are sold. A pharmacy is, by law, constantly supervised by a licensed pharmacist.
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Pneumonia: Inflammation of one or both lungs with consolidation. Pneumonia is frequently but not always due to infection. The infection may be bacterial, viral, fungal or parasitic. Symptoms may include fever, chills, cough with sputum production, chest pain, and shortness of breath.
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Positron emission tomography: PET. A highly specialized imaging technique that uses short-lived radioactive substances to produce three-dimensional colored images of those substances functioning within the body. These images are called PET scans and the technique is termed PET scanning.
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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.
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Primary tumor: A tumor that is at the original site where it first arose. For example, a primary brain tumor is one that arose in the brain as opposed to one that arose elsewhere and metastasized (spread) to the brain. The original tumor is sometimes called "the primary."
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Progressive: Increasing in scope or severity. Advancing. Going forward. In medicine, a disease that is progressive is going from bad to worse.
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Pulmonary: Having to do with the lungs. (The word comes from the Latin pulmo for lung).
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Radiologic: Having to do with radiology.
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Radon: A radioactive element formed as a gas during the breakdown of radium.
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Red blood cells: The blood cells that carry oxygen. Red cells contain hemoglobin and it is the hemoglobin which permits them to transport oxygen (and carbon dioxide). Hemoglobin, aside from being a transport molecule, is a pigment. It gives the cells their red color (and their name).
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Resolution: In genetics , resolution refers to the degree of molecular detail on a physical map of DNA , ranging from low to high.
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Respiratory: Having to do with respiration, the exchange of oxygen and carbon dioxide. From the Latin re- (again) + spirare (to breathe) = to breathe again.
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Rheumatoid arthritis : An autoimmune disease which causes chronic inflammation of the joints, the tissue around the joints, as well as other organs in the body. Autoimmune diseases occur when the body tissues are mistakenly attacked by its own immune system. The immune system is a complex organization of cells and antibodies designed normally to "seek and destroy" invaders of the body, particularly infections. Patients with these diseases have antibodies in their blood which target their own body tissues, where they can be associated with inflammation. Because it can affect multiple other organs of the body, rheumatoid arthritis is referred to as a systemic illness and is sometimes called rheumatoid disease. While rheumatoid arthritis is a chronic illness (meaning it can last for years) patients may experience long periods without symptoms.
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Sarcoidosis: A disease of unknown origin that causes small lumps (granulomas) due to chronic inflammation to develop in a great range of body tissues. Sarcoidosis can appear in almost any body organ, but most often starts in the lungs or lymph nodes. It also affects the eyes, liver and skin; and less often the spleen, bones, joints, skeletal muscles, heart and central nervous system (brain and spinal cord).
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Sarcoma: One of a group of tumors usually arising from connective tissue . Most sarcomas are malignant . Many types are named after the type of cell, tissue, or structure involved, as in angiosarcoma , chondrosarcoma , fibrosarcoma , liposarcoma,and osteosarcoma .
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Scan: As a noun, the data or image obtained from the examination of organs or regions of the body by gathering information with a sensing device.
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Sedimentation rate : A blood test that detects and monitors inflammation in the body. It measures the rate at which red blood cells (RBCs) in a test tube separate from blood serum over time, becoming sediment in the bottom of the test tube. The sedimentation rate increases with more inflammation. Also called the erythrocyte sedimentation rate. Abbreviated as sed rate or ESR.
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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.
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Serum: The clear liquid that can be separated from clotted blood. Serum differs from plasma, the liquid portion of normal unclotted blood containing the red and white cells and platelets. It is the clot that makes the difference between serum and plasma.
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Specificity: 1. The quality of being specific as, for example, she showed the use of specificity in her diagnosis. 2. The proportion of persons without a disease who are correctly identified by a test. The specificity is the number of true negative results divided by the sum of the numbers of true negative plus false positive results.
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SPECT: An acronym that stands for Single Photon Emission Computed Tomography, a nuclear medicine procedure in which a gamma camera rotates around the patient and takes pictures from many angles, which a computer then uses to form a tomographic (cross-sectional) image.
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Stage: As regards cancer , the extent of a cancer, especially whether the disease has spread from the original site to other parts of the body. See also: Staging .
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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 .
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Surgeon: A physician who treats disease, injury, or deformity by operative or manual methods. A medical doctor specialized in the removal of organs, masses and tumors and in doing other procedures using a knife (scalpel). The definition of a "surgeon" has begun to blur in recent years as surgeons have begun to minimize the cutting, employ new technologies that are "minimally invasive," use scopes, etc.
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Surgery: The word "surgery" has multiple meanings. It is the branch of medicine concerned with diseases and conditions which require or are amenable to operative procedures. Surgery is the work done by a surgeon. By analogy, the work of an editor wielding his pen as a scalpel is s form of surgery. A surgery in England (and some other countries) is a physician's or dentist's office.
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Symptom: Any subjective evidence of disease. Anxiety, lower back pain , and fatigue are all symptoms. They are sensations only the patient can perceive. In contrast, a sign is objective evidence of disease. A bloody nose is a sign. It is evident to the patient, doctor, nurse and other observers.
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Tapeworm:A worm that is flattened like a tape measure and functions as an intestinal parasite, unable to live freely on its own but able to do so within an animal's gut. The eggs usually enter the body via raw or uncooked beef. Symptoms of their presence are usually absent. However, some patients experience abdominal pain , fatigue, weight loss, and diarrhea . Treatment with medication results in a cure within days.
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Thoracotomy: An operation to open the chest.
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Tomography: The process for generating a tomogram , a two-dimensional image of a slice or section through a three-dimensional object. Tomography achieves this remarkable result by simply moving an x-ray source in one direction as the x-ray film is moved in the opposite direction during the exposure to sharpen structures in the focal plane, while structures in other planes appear blurred. The tomogram is the picture; the tomograph is the apparatus; and tomography is the process.
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Tuberculin: A protein extracted from Mycobacterium tuberculosis that is used in a skin test to determine if a person has been exposed to tuberculosis. The tuberculin preparation in most common use today is purified protein derivative (PPD) tuberculin. PPD is injected (or multiple-punctured) into the skin. If a reaction is seen at and around the site of injection, the test is positive. The PPD tuberculin test done by intradermal injection is also known as the Mantoux test.
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Tuberculosis : A highly contagious infection caused by the bacterium called Mycobacterium tuberculosis. Abbreviated TB. Tubercles (tiny lumps) are a characteristic finding in TB. Diagnosis may be made by skin test, which if positive should will be followed by a chest X-ray to determine the status (active or dormant) of the infection. Tuberculosis is more common in people with immune system problems, such as AIDS, than in the general population. Treatment of active tuberculosis is mandatory by law in the US, and should be available at no cost to the patient through the public health system. It involves a course of antibiotics and vitamins that lasts about six months. It is important to finish the entire treatment, both to prevent reoccurrence and to prevent the development of antibiotic-resistant tuberculosis. Most patients with tuberculosis do not need to be quarantined, but it is sometimes necessary.
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Tumor: An abnormal mass of tissue. Tumors are a classic sign of inflammation, and can be benign or malignant (cancerous). There are dozens of different types of tumors. Their names usually reflect the kind of tissue they arise in, and may also tell you something about their shape or how they grow. For example, a medulloblastoma is a tumor that arises from embryonic cells (a blastoma) in the inner part of the brain (the medulla). Diagnosis depends on the type and location of the tumor. Tumor marker tests and imaging may be used; some tumors can be seen (for example, tumors on the exterior of the skin) or felt (palpated with the hands).
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Vinyl chloride: A substance used in manufacturing plastics that is known to be toxic and carcinogenic (cancer-causing). Dangerous exposure to vinyl chloride occurs mainly in the workplace. Breathing high levels of vinyl chloride for short periods of time can cause dizziness, sleepiness, unconsciousness and, at extremely high levels, death. Breathing vinyl chloride for long periods of time can result in permanent liver damage, nerve damage, liver cancer , brain tumors , lung cancer , and malignancies of the digestive tract.
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Virus: A microorganism smaller than a bacteria, which cannot grow or reproduce apart from a living cell. A virus invades living cells and uses their chemical machinery to keep itself alive and to replicate itself. It may reproduce with fidelity or with errors (mutations)-this ability to mutate is responsible for the ability of some viruses to change slightly in each infected person, making treatment more difficult.
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Windpipe: The trachea, a tube-like portion of the respiratory (breathing) tract that connects the larynx (the voicebox) with the bronchial parts of the lungs.


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X-ray: 1. High-energy radiation with waves shorter than those of visible light. X-rays possess the properties of penetrating most substances (to varying extents), of acting on a photographic film or plate (permitting radiography), and of causing a fluorescent screen to give off light (permitting fluoroscopy). In low doses X-rays are used for making images that help to diagnose disease, and in high doses to treat cancer . Formerly called a Roentgen ray. 2. An image obtained by means of X-rays.
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