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1-10 A B C D E F G H I J K L M N O P Q R S T U V W XYZIdiopathic
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Idiopathic denotes a disease of unknown cause.
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The iliocostalis is the lateral division of the erector spinae, having three subdivisions: musculus iliocostalis lumborum, m. i. thoracis and m. i. cervicus.
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Immune cells attack unrecognized or foreign substances in the body in order to destroy harmful invaders and prevent infection and disease. See also B-cell or T-cell.
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The immune system provides the body with a defense against infection, afforded by the presence of circulating antibodies and white blood cells. Antibodies are manufactured specifically to deal with the antigens associated with different diseases as they are encountered, while white blood cells attack and destroy foreign particles in the blood and tissues.
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Immunity refers to the quality of being insusceptible to or unaffected by a particular disease or condition. Active immunity refers to a form of long-term, acquired immunity that protects the body against a new infection as a result of antibodies after an initial infection or artificially after immunization. Passive immunity refers to a form of immunity resulting from antibodies that are transmitted naturally through the placenta to a fetus or through the colostrum to an infant or artificially by injection of antiserum for treatment or prophylaxis. Passive immunity is not permanent and does not last as long as active immunity.
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Immuno-hematology is the study of antigen-antibody reactions and their effects on blood.
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Immunocompetence pertains to the ability to produce a normal immune response.
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The immunofluorescent antibody technique uses fluorescein-labeled antibodies to identify bacterial, viral or other antigenic material specific for the labeled antibody. Fluorescence microscopy is used to determine the specific binding of antibody through the production of a characteristic visible light that occurs upon application of ultraviolet rays to the preparation.
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An immunoglobulin is one of a class of structurally related proteins consisting of two pairs of polypeptide chains, one pair of light (L) low molecular weight chains and one pair of heavy (H) chains, all four linked together by disulfide bonds. On the basis of the structural and antigenic properties of the H chains, Ig's are classified (in order of relative amounts present in normal human serum) as IgG, IgA, IgM, IgD and IgE. Antibodies are Ig's, and all Ig's probably function as antibodies.
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Immunoglobulin A (IgA) comprises about 10-15% of the body's total immunoglobulins. It is the major class of antibodies in external secretions, such as saliva, tears, breast milk, bronchial mucous and intestinal mucous. IgAs are secreted on the body's surfaces as the first defense against bacterial and viral antigens thus preventing entry into the body. IgAs may be an important and effective antibody in areas other than mucosal tissues, such as the central nervous system.
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Immunoglobulin G (IgG), the most common type of antibody, comprises about 80% of the body's total immunoglobulins. It is the principal antibody in the serum and is produced in large quantities during secondary immune responses which, with IgM, activate the complement system. IgGs act on pathogens by agglutinating them, by opsonising them, by activating complement-mediated reactions against cellular pathogens and by neutralizing toxins.
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Immunoglobulin M (IgM) comprises 5-10% of the body's total immunoglobulins. It is the first antibody to appear in the serum after injection of an antigen and is produced during primary immune responses. It is capable of capturing and binding antigens to form large insoluble complexes which are readily cleared from the blood. IgM levels may be elevated in patients with delayed patterns of food allergy and manifest a protective defense response.
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Immunohematologic refers to a branch of immunology that deals with the immunologic properties of blood.
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Immunological relates to immunology, the study of the immune system. The immune system provides the body with a defense against infection via circulating antibodies and white blood cells. Antibodies are manufactured specifically to immediately deal with the antigens associated with different diseases as they are encountered, while white blood cells attack and destroy foreign particles in the blood and tissues.
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Immunology is the study of the immune system. The immune system provides the body with a defense against infection via circulating antibodies and white blood cells. Antibodies are manufactured specifically to immediately deal with the antigens associated with different diseases as they are encountered, while white blood cells attack and destroy foreign particles in the blood and tissues.
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Immunophenotyping is the recording of observable immunological characteristics of an individual, which result from interaction between the genes of that individual and the environment.
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Immunoreactive is used to describe a situation where an antigen and antibody are reactive in vitro (occurring outside the body, traditionally in a test tube).
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Immunoreactive growth hormone (IRGH) is an interactive form of the growth hormone that also triggers immunoreactions (between antigen and antibody).
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Impaction means the effect of one thing on another.
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Impedance is a measure of the total opposition to current flow in an alternating-current circuit.
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Implantation (nidation) is the attachment of the early embryo to the lining of the womb, usually six to eight days after ovulation. The site of implantation determines the position of the placenta.
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In vitro is a Latin term describing biological phenomena that are made to occur outside the living body (traditionally in a test tube).
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In vivo is a Latin term describing biological phenomena that occur,or are observed occurring, within the bodies of living organisms.
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In-situ is the Latin term for "in the original place".
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Inclination is the degree of deviation from a horizontal or vertical line. The inclination of the Space Shuttle as it orbits the Earth is tracked during missions, since its inclination determines the stability of the spacecraft . At some inclinations, the Shuttle is more stable than others, which means it requires less fuel to keep it in orbit and provides a better environment for some gravity-sensitive experiments.
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To incubate is to artificially warm (and hatch eggs) by maintaining conditions similar to body heat.
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An incubator is a device which maintains controlled environmental conditions, especially used for providing warmth and dryness. Some incubators are specifically designed for cultivating cell cultures and bacteria in Petri dishes. Others are designed for hatching eggs or for protecting animal or human infants.
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Inertia is the tendency of a body to resist acceleration, or to resist motion, action or change.
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The Inertial Measurement Unit (IMU) is a Shuttle orbiter navigation system which provides attitude and velocity data to the Guidance, Navigation, and Control (GNC) system.
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The inertial property of mass states that matter will remain at rest or in uniform motion in the same straight line unless acted upon by an external force.
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Infiltrates are substances that seep through a filter.
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Influent refers to something which flows in or into.
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Influenza is an acute infectious respiratory disease, in which the inhaled virus attacks the respiratory epithelial cells of susceptible persons and produces an inflammation of the mucous membrane.
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Influenza virus is of the genus Orthomyxoviridae, which comprises the influenza viruses types A and B. Each type of virus has a stable nucleoprotein group antigen common to all strains of the type, but distinct from that of the other type; each also has a mosaic of surface antigens (hemagglutinin and neuraminidase) which characterize the strains. Strain notations indicate (1) type, (2) geographic origin, (3) year of isolation and (4) in the case of type A strains, the characterizing subtypes of hemagglutinin and neuraminidase antigens (e.g., A/HongKong/1/68 (H3N2)).
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Infrared is the part of the invisible spectrum that is contiguous to the red end of the visible spectrum.
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Infrared anatomical photography is a type of photography that uses heat sensitive film to see the regions of the body that give off heat.
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Inguinal is relating to the groin.
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Innate means possessed as an essential characteristic; inherent.
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The inner ear (or labyrinth) is a convoluted system of cavities and ducts comprising the organs of hearing and balance.
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Inoculate is to introduce a substance (inoculum) into the body to produce or to increase immunity to the disease or condition associated with the substance.
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Inorganic means of or originating from non-carbon based compounds.
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Inotropic means influencing the contractility of muscular tissue.
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Insomnia is a prolonged inability to obtain adequate sleep; abnormal wakefulness. Insomnia is actually a symptom that may be caused by many conditions, including stress, depression, pain, or similar problems.
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Insulin is a hormone secreted by the pancreas. It promotes glucose utilization, protein synthesis, and the formation and storage of lipids. Its chemical structure is completely known and insulin obtained from various animals is used in the treatment of diabetes.
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Insulin like growth factor (IGF1), also known as somatomedin, is a peptide synthesized in the liver (and probably in the kidney) that is capable of stimulating certain anabolic processes in bone and cartilage, such as the synthesis of DNA and RNA protein and the sulfation of mucopolysaccharides. Its secretion and/or biological activity is known to be dependent on growth hormone (also called somatotropin).
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To minimize the amounts of blood, urine, and saliva taken from crew members, investigators share samples (e.g. one sample is drawn, processed and distributed to multiple investigators, who then perform their own unique analysis) in Integrated Metabolic Sessions.
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Integumentary relates to the rind, capsule or covering of any body part.
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The interaural axis is the imaginary line that runs between and connects the auricles (outer ears).
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Intercostal means between the ribs.
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The field of interdisciplinary physiology focuses on understanding how the changes in one system of the body affects another system. In space, many processes change as a result of the nearly complete loss of gravity's downward pull. For example, microgravity causes a headward shift in fluid which changes the normal state of physiology and affects several systems of the body.
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An interferometer is a device that is used to study a sample of protein solution by passing a laser light through the sample.
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Interferon is a substance that is produced by cells infected with a virus and has the ability to inhibit viral growth. Gamma interferon is one of the three distinct types: alpha, beta and gamma.
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Interindividual means between two or more individuals; e.g., interindividual differences.
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Interleukin is a family of proteins that controls aspects of the production of blood cells and platelets (hemopoiesis) and the immune response. Eight interleukins are currently characterized; interleukin 2, for instance, stimulates T-lymphocytes and is being investigated for the treatment of cancer.
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The IML, or International Microgravity Laboratory, missions were a series of Spacelab missions that emphasized international cooperation between the European Space Agency (ESA), The Japanese Space Agency (NASDA), the Canadian Space Agency (CSA) and NASA. These missions were dedicated to the study of both life and microgravity sciences; the life sciences experiments focused on space biology (plant, cell, and molecular and developmental biology).
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International partners, space agencies and scientists from foreign countries, cooperate with the United States space agency (NASA) and U.S. scientists to conduct experiments in space. For example, the International Microgravity Laboratory-1 (IML-1) was a cooperative effort between NASA and the European Space Agency, while the Spacelab-Mir missions are a cooperative effort between the U.S. and Russia.
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Interpupillary means between the pupils.
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Interstitial means relating to spaces or interstices (small area, space or hole in the substance of an organ or tissue) in any structure.
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Intervertebral refers to the flexible plate of fibrocartilage that connects any two adjacent vertebrae in the backbone or spine.
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An intervertebral disc is the flexible plate of fibrocartilage that connects any two adjacent vertebrae in the backbone or spine.
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The intervertebral disc space is the space between any two vertebrae of the backbone or spine containing the intervertebral disc, a flexible plate of fibrocartilage. During exposure to microgravity this space expands, causing a height change of up to 2 inches in the astronauts while in space.
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Intra-acinar means inside the acinus of the lungs. The term acinus refers to that part of the airway that contains the respiratory bronchiole and all of its branches.
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Intra-carotid means inside the carotid artery.
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Intracellular fluid is the fluid located within cells.
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Intracellular fluid volume (ICFV) is the fluid volume located within cells.
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Intraindividual means between measurements from the same individual; e.g., intraindividual differences.
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Intraocular denotes a location inside the eyeball.
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Intraocular pressure is the pressure within the eyeball.
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Intraocular tension, also called intraocular pressure, is the pressure of the fluids of the eye.
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Intraperitoneal refers to location within the serous membrane of the abdominal cavity called the peritoneum.
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Intrapleural refers to a location within the pleura, either the covering of the lungs (visceral pleura) or of the inner surface of the chest wall (parietal pleura).
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Intravascular refers to any location within the system of blood vessels.
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Intravenous means into or within a vein. An intravenous injection is made into a vein.
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An IV pump is a mechanical pump utilized to inject or pump fluid or solution into a vein of the human body.
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Intrinsic refers to those muscles whose origin and insertion are both in the same limb or segment of a limb. Intrinsic lower back muscles have both their origin and insertion in the lower back.
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Inutest is a substance similar to the polysaccharide inulin. It is used to test the plasma clearance, or the ability of the kidneys to clean plasma of various substances. Glomerular filtrate and plasma are very similar, except that plasma contains all the proteins which are retained in the body and not cleared in the filtrate. Glomerular filtrate and plasma contain the same concentration of inulin, therefore all glomerular filtrate is cleared of inulin. So inulin is a good measure of glomerular filtration rate and plasma clearance.
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An invertebrate is any animal that does not have a backbone.
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Iodine is an element required in small amounts for healthy growth and development. An adult body contains about 30 mg of iodine, mostly concentrated in the thyroid gland where it is needed to synthesize thyroid hormones.
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Iodine 125 (I 125) is a radioactive isotope of iodine. It is used as an active tracer that binds to serum plasma. By measuring the amount of radioactivity emitted by I 125, plasma volume can be measured.
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Iodine 131 is a radioactive tracer that binds to blood albumin. It is used to measure total circulating blood volume.
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Iodine-125 is a radioactive isotope used as a tracer in thyroid studies, as therapy in hyperthyroidism and in thyroid cancer, and as a label in immunoassay.
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An ion is an atom or group of atoms that has acquired an electric charge through the gain or loss of an electron or electrons.
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Ionization is the process of disassociating atoms or molecules as when they are subject to electrical discharge. An ion is an atom, group of atoms, or molecule having an electric charge by virtue of gaining or losing electrons from three initial neutral configuration.
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To ionize means to separate into ions; that is, to dissociate atoms or molecules into electrically charged atoms or radicals.
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Ionized calcium is the ionic (i.e., charged) form of calcium that plays a role in muscle contractions and in regulating levels of parathyroid hormone (PTH).
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Radiation, such as that found in cosmic rays, causes atoms in the material through which it passes to lose electrons. The electrons are pulled away from the atoms by the strong attractive force between the positively charged proton (or heavy ion) and the orbital electron. Ionizing radiation can kill cells outright, damage their genetic material, and, in some instances, induce cancer.
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Iron is an essential element found in hemoglobin and myoglobin molecules. It is needed for hemoglobin production.
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Iron economy refers to the measurement of red blood cell production and destruction by the process of using a radioactive isotope of iron as a type of tag. The radioactive iron is injected in harmless levels into the blood where it tags or marks the red blood cells. Afterwards, newly produced cells will be free of the isotope and destroyed, tagged cells can be counted. The balance between supply and destruction of red blood cells is termed iron economy.
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Iron kinetics is the study of the rate of change of iron in the body.
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An irritant is something which causes inflammation, soreness, roughness, or irritability of a body part.
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Isoagglutinin is an isoantibody that causes cells to adhere or to form clumps.
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Isocapnia is a state in which carbon dioxide pressure in the arteries remains constant.
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An isoenzyme (or isozyme) is one of a group of enzymes that are very similar in catalytic properties, but may be differentiated by variations in physical properties, such as isoelectric point or electrophoretic mobility.
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Isokinetic relates to movement of the body.
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An isokinetic dynamometer is a device that measures the strength of different muscle groups.
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Isolation is the state of being free from external influence.
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Isometric describes the contraction of muscles when the fibers increase in tension, but do not shorten in length. Isometric exercises can be induced in muscles that are used when a limb is made to pull or push against something that does not move.
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Isoproterenol is a chemical used as a drug which acts to stimulate the heart and open the air passages in asthma and other bronchial conditions.
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Isotachophoresis means "equal speed." The method consists of placing a mixture of charged particles (sample) of the same sign (co-ions) in a column or on some solid support medium containing two additional electrolytes. One electrolyte has co-ions more mobile than the sample co-ions, while the other electrolyte has co-ions less mobile than the sample co-ions. Upon application of a constant direct current, the sample co-ions initially move at different velocities until a steady state is reached. The sample ions will separate into contiguous zones with sharp interfaces in order of their mobilities. The boundaries are highly self-recuperative and will reform if stirred or disrupted by other factors, including convection.
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Isothermal means with or at equal temperatures, or at a constant temperature.
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Isotonic means under constant or uniform tension. It denotes the condition of a contracting muscle shortening against a constant load, such as occurs when lifting a weight. Isotonic also refers to solutions in which cells can be bathed without a net flow of water through the cell membrane, or two or more solutions having the same concentration of osmotically active substances (salts, sugars, proteins, etc.).
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An isotope is one of two or more atoms of the same chemical element that have the same number of protons in their nucleus but different numbers of neutrons. Most elements in nature consist of a mixture of isotopes. Example: hydrogen is known to have three isotopes - hydrogen (1 proton, no neutrons), deuterium (1 proton, 1 neutron), and tritium (1 proton, 2 neutrons).
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Isotopic refers to an isotope, the term used to describe that an element has two or more chemical properties, with the same number of protons, but different numbers of neutrons in their nucleus.
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Isotypes refer to the classes of immunoglobulins IgG, IgA,IgM, IgD, and IgE which have similar structures but differ in molecular weight and concentration in the blood.
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Isovelocity is an equal or constant rate of movement, such as distance/time or work/time.
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An IV pump (intravenous pump) is a mechanical pump that maintains a steady flow of fluid into a vein.