|Medical Dictionary - Dictionary of Medicine and Human Biology|
The motility of the auditory outer hair cells in response to electrical stimulation.
electromyogram (EMG) (e-lek-tro-mi′o-gram)
A graphic representation of the electric currents associated with muscular action.
An instrument for recording electrical currents generated in an active muscle.
1. The recording of electrical activity generated in muscle for diagnostic purposes; both surface and needle recording electrodes can be used, although characteristically the latter is employed, so that the procedure is also called needle electrode examination. 2. Umbrella term for the entire electrodiagnostic study performed in the EMG laboratory, including not only the needle electrode examination, but also the nerve conduction studies. [electro- + G. mys, muscle, + grapho, to write] evoked e. SYN: electrodiagnosis.
electron (β−) (e-lek′tron)
One of the negatively charged subatomic particles that orbit the positive nucleus, in one of several energy levels called shells; in mass they are estimated to be 1/1836.15 of a proton; when emitted from inside the nucleus of a radioactive substance, electrons are called β particles. A nucleus and its electrons constitute an atom. SEE ALSO: shell. [electro- + -on] Auger e. an e. ejected from an orbital by photoelectric interaction with a photon emitted when another e., in a higher energy orbital, passed from a higher to a lower energy level; the Auger e. recoils with energy equal to the characteristic radiation less the difference in shell binding energies. See photoelectric effect, transition e.. conversion e. an internal conversion e.. emission e. a beta particle resulting from radioactive decay. internal conversion e. an e., similar to an Auger e., released from one of the e. orbits of the atom upon activation by a gamma ray from that atom's nucleus; the e. has kinetic energy equal to the net energy transition of the disintegration. positive e. SYN: positron. transition e. an e. that moves from one energy level to another to fill a vacancy in a shell, with the emission of characteristic radiation. valence e. one of the electrons that take part in chemical reactions of an atom.
Production of insensibility to pain by the use of electrical current.
1. Relating to or charged with negative electricity. 2. Referring to an element whose uncharged atoms have a tendency to ionize by adding electrons, thus becoming anions ( e.g., oxygen, fluorine, chlorine).
SYN: electrodiagnosis (2) .
Destruction of nerve tissue by electricity.
See electrodiagnosis (2) .
1. Pertaining to electrons. 2. Denoting devices or systems utilizing the flow of electrons in a vacuum, gas, or semiconductor.
electron-volt (eV, ev)
The energy imparted to an electron by a potential of 1 V; equal to 1.60218 × 10−12 erg in the CGS system, or 1.60218 × 10−19 J in the SI system.
electronystagmography (ENG) (e-lek′tro-nis′tag-mog′ra-fe)
A method of nystagmography based on electrooculography; skin electrodes are placed at outer canthi to register horizontal nystagmus or above and below each eye for vertical nystagmus. [electro- + nystagmus + G. grapho, to write]
A record of electric currents in electro-oculography.
electrooculography (EOG) (e-lek′tro-ok′u-log′ra-fe)
Oculography in which electrodes placed on the skin adjacent to the eyes measure changes in standing potential between the front and back of the eyeball as the eyes move; a sensitive electrical test for detection of retinal pigment epithelium dysfunction.
electroolfactogram (EOG) (e-lek′tro-ol-fak′to-gram)
An electronegative wave of potential occurring on the surface of the olfactory epithelium in response to stimulation by an odor. SYN: osmogram, Ottoson potential.
The diffusion of a substance through a membrane in an electric field. Cf.:electrodialysis.
Removal of fluid, as from the eye, with an electrically activated instrument.
The densitometric or colorimetric pattern obtained from filter paper or similar porous strips on which substances have been separated by electrophoresis; may also refer to the strips themselves. SYN: electrophoretogram, ionogram, ionopherogram.
electrophil, electrophile (e-lek′tro-fil, -fil)
1. The electron-attracting atom or agent in an organic reaction. Cf.:nucleophil. 2. Relating to an e.. SYN: electrophilic. [electro- + G. philos, fond]
SYN: electrophil (2) .
Morbid fear of electricity. [electro- + G. phobos, fear]
The movement of particles in an electric field toward an electric pole (anode or cathode); used to separate and purify biomolecules. SEE ALSO: electropherogram. SYN: dielectrolysis, ionophoresis, phoresis (1) . [electro- + G. phoresis, a carrying] capillary zone e. (CZE) a method for separating molecules extremely rapidly based on their electrophoretic mobility. carrier e. e. done on a carrier (such as paper, polyacrylamide gel, etc.). disk e. a modification of gel e. in which a discontinuity (pH, gel pore size) is introduced near the origin to produce a lamina (disk) of the materials being separated; the separating bands retain their discoid shape as they move through the gel. free e. e. of substances placed in a solution in a U-shaped tube. gel e. e. through a gel, usually a cylindrical tube or on a slab consisting of a gel of uniform composition. isoenzyme e. electrophoretic separation of serum enzymes; separation of lactate dehydrogenase and creatine phosphokinase is commonly used for diagnosis of acute myocardial infarction. lipoprotein e. electrophoretic separation of plasma lipoproteins. polyacrylamide gel e. (PAGE) a gel formed by cross-linking of acrylamide that is used for the separation of proteins or nucleic acids. These substances are separated on the basis of both size and charge. pulsed-field gel e. SYN: pulse-field gel e.. pulse-field gel e. gel e. in which, after electrophoretic migration has begun, the current is briefly stopped and reapplied in a different orientation; allows for the purification of long DNA molecules. SYN: pulsed-field gel e.. thin-layer e. (TLE) electrophoretic migrations (separations) through a thin layer of inert material, such as cellulose, supported on a glass or plastic plate.
Relating to electrophoresis, as an e. separation. SYN: ionophoretic.
Denoting electrical stimulation of the phrenic nerve usually at its motor point in the neck. SEE ALSO: e. respiration.
The branch of science concerned with electrical phenomena that are associated with physiologic processes. Electrical phenomena are prominent in neurons and effectors.
A technique in which a brief electric shock is applied to cells; momentary holes open briefly in the plasma membrane, allowing the entry of macromolecules ( e.g., a way of introducing new DNA into a cell).
1. Relating to or charged with positive electricity. 2. Referring to an element whose atoms tend to lose electrons; e.g., sodium, potassium, calcium.
Passage of an electrical current through needle electrodes piercing the tissues.
Obsolete term for the use of electricity and x-ray in treatment.
A modified electroscope designed for the differentiation of radiant energy. [electro- + L. radius, ray, + G. metron, measure]
electroretinogram (ERG) (e-lek′tro-ret′i-no-gram)
A record of the retinal action currents produced in the retina by an adequate light stimulus. [electro- + retina + G. gramma, something written]
The recording and study of the retinal action currents.
Division of tissues by means of an electrocautery knife. [electro- + L. scissio, a splitting, fr. scindo, to split]
An instrument for the detection of electrical charges or ionization of gas by beta or x-rays; consists of two strips of gold leaf suspended from an insulated conductor and enclosed in an airtight container viewed with a low-power microscope. [electro- + G. skopeo, to examine]
See e. therapy.
SYN: colloidal metal.
The recording, study, and interpretation of electroencephalographic wave patterns.
The record obtained by electrospinography.
The recording of spontaneous electrical activity of the spinal cord.
The precipitation of metals in membrane pores in the course of electrolysis.
Electrical instrument that amplifies or records the respiratory and cardiac sounds of the chest. [electro- + G. stethos, chest, + grapho, to record]
1. The contraction in volume in a protein solution during proteolysis due to the formation of new charged groups. 2. The reversible change in dimensions of a substance or material when an electric field is applied to it.
Division of tissues by high frequency current applied locally with a metal instrument or needle. SEE ALSO: electrocautery. SYN: electrotomy.
Reaction of plant or animal protoplasm to either an anode or a cathode. SEE ALSO: tropism. SYN: electrotropism, galvanotaxis, galvanotropism. [electro- + G. taxis, orderly arrangement] negative e. e. by which an organism is attracted toward an anode or repelled from a cathode. positive e. e. by which an organism is attracted toward a cathode or repelled from an anode.
SYN: electrocution. [electro- + G. thanatos, death]
electrotherapeutics, electrotherapy (e-lek′tro-thar-a-pu′tiks, -thar′a-pe)
Use of electricity in the treatment of disease.
A flexible sheet of resistance coils used for applying heat to the surface of the body. [electro- + G. therme, heat]
An electric scalpel.
SYN: electrosurgery. [electro- + G. tome, incision]
Relating to electrotonus.
Changes in excitability and conductivity in a nerve or muscle cell caused by the passage of a constant electric current. SEE ALSO: catelectrotonus, anelectrotonus. SYN: galvanotonus (1) . [electro- + G. tonos, tension]
electrotropism (e-lek-trot′ro-pizm, e-lek-tro-tro′pizm)
SYN: electrotaxis. [electro- + G. trope, a turning]
SYN: confection. [G. eleikton, a medicine that melts in the mouth, fr. ekleicho, to lick up]
An undecapeptide toxin that is formed in the venom gland of cephalopods of the genus Eledone and causes vasodilation and contraction of extravascular smooth muscle.
A refractile and weakly staining keratin present in the cells of the stratum lucidum of the palmar and plantar epidermis.
1. A substance composed of atoms of only one kind, i.e., of identical atomic (proton) number, that therefore cannot be decomposed into two or more elements and that can lose its chemical properties only by union with some other e. or by a nuclear reaction changing the proton number. 2. An indivisible structure or entity. 3. A functional entity, frequently exogenous, within a bacterium, such as an extrachromosomal e.. [L. elementum, a rudiment, beginning] actinide elements SYN: actinides. alkaline earth elements those elements in the family Be, Mg, Ca, Sr, Ba, and Ra, the hydroxides of which are highly ionized and hence alkaline in water solution. amphoteric e. an e., one or more of whose oxides unite with water to form hydroxides that may act as acids or as bases ( e.g., aluminum). anatomical e. any anatomical unit, such as a cell. SYN: morphologic e.. copia elements a mobile genetic e. with retrovirus-like sequence organization. electronegative e. an e. whose atoms have a tendency to accept electrons and form negative ions ( e.g., oxygen, sulfur, chlorine). electropositive e. an e. whose atoms have a tendency to lose electrons and form positive ions ( e.g., sodium). extrachromosomal e., extrachromosomal genetic e. SYN: plasmid. fold-back elements a type of transposable e. that possesses long inverted repeats, such that when denatured, loops are formed. labile elements tissue cells, as of epithelium, connective tissue, etc., that continue to multiply by mitosis during the life of the individual. long interspersed elements (LINES) long repetitive sequences in DNA with terminal repeats seen in human and mouse DNA. morphologic e. SYN: anatomical e.. neutral e. an e. of the zero group of the periodic system comprising the noble gases, He, Ne, Ar, Kr, Xe, Rn. noble e. SYN: noble metal. P elements a class of transposable elements in Drosophila responsible for hybrid dysgenesis; utilized as tools for introducing genes into new locations in the genome. picture e. pixel. rare earth elements SYN: lanthanides. short interspersed elements (SINES) highly repetitive sequences of DNA of about 300 base pairs in length that occur about every 3000–5000 bp in the genome. trace elements elements present in minute amounts in the body, many of which are essential in metabolism or for the manufacture of essential compounds; e.g., Zn, Se, V, Ni, Mg, Mn. SYN: microelements, microminerals. transposable e. a DNA sequence that can move from one location in the genome to another; the transposition event can involve both recombination and replication, producing two copies of the moving piece of DNA; the insertion of these DNA fragments can disrupt the integrity of the target gene, possibly causing activation of dormant genes, deletions, inversions, and a variety of chromosomal aberrations. SEE ALSO: transposon. volume e. voxel.
Oil. SEE ALSO: oleo-. [G. elaion, olive oil]
SYN: lipogranuloma. [G. elaion, oil, + -oma, tumor]
SYN: oleometer. [G. elaion, oil, + metron, measure]
A rare condition in which there is boggy swelling of the joints, said to be due to a fatty deposit following contusion; or possibly a condition resulting from the injection of paraffin oil as a form of malingering. SYN: elaiopathia.
eleostearic acid (el-e-o-ste′a-rik, -ster′ik)
An 18-carbon fatty acid with three double bonds (at carbons 9, 11, and 13); isomeric with linolenic acid; found in plant fats.
SYN: oleotherapy. [G. elaion, oil]
Hypertrophy, edema, and fibrosis of the skin and subcutaneous tissue, especially of the lower extremities and genitalia with hydrocele, or enlargement of a limb, usually caused by long-standing obstructed lymphatic vessels, most commonly the result of years of infection by the filarial worm Wuchereria bancrofti or Brugia malayi. SEE ALSO: filariasis. SYN: elephant leg. [G. fr. elephas, elephant] congenital e. congenital enlargement of one or more of the limbs or other parts, due to dilation of the lymphatics. See also entries under hereditary lymphedema, congenital type. gingival e. a fibrous hyperplasia of the gingiva. e. neuromatosa enlargement of a limb due to diffuse neurofibromatosis of the skin and subcutaneous tissue. e. scroti brawny swelling of the scrotum as a result of chronic lymphatic obstruction. SYN: lymph scrotum, parasitic chylocele. e. telangiectodes hypertrophy of the skin and subcutaneous tissues accompanied by and dependent upon dilation of the blood vessels. e. vulvae SYN: chronic hypertrophic vulvitis.
elevation (el-e-va′shun) [TA]
SYN: torus (1) . e. of levator palati SYN: torus levatorius. tactile elevations [TA] small areas in the skin of the palms and soles especially rich in sensory nerve endings. SYN: toruli tactiles [TA] .
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