Medical Dictionary banner
Medical Dictionary - Dictionary of Medicine and Human Biology

Medical Dictionary


gnat (nat)
A midge; general term applied to several species of minute insects, including species of Simulium (buffalo g.) and Hippelates (eye g.). British authors sometimes include mosquitoes in this group, but this is not done in the U.S. [A.S. gnaet]

See gnatho-.

gnathic (nath′ik)
Relating to the jaw or alveolar process. [G. gnathos, jaw]

gnathion (nath′e-on)
The most inferior point of the mandible in the midline. In cephalometrics, it is the midpoint between the most anterior and inferior point on the bony chin, measured at the intersection of the mandibular baseline and the nasion-pogonion line. [G. gnathos, jaw]

gnatho-, gnath-
The jaw. [G. gnathos]

gnathocephalus (nath-o-sef′a-lus)
A fetal malformation with little of the head formed except the jaws. [gnatho- + G. kephale, head]

gnathodynamics (nath′o-di-nam′iks)
The study of the relationship of the magnitude and direction of the forces developed by and upon the components of the masticatory system during function. [gnatho- + G. dynamis, power]

gnathodynamometer (nath′o-di-na-mom′e-ter)
A device for measuring biting pressure. SYN: bite gauge, occlusometer. [gnatho- + dynamometer]

gnathography (na-thog′ra-fe)
The recording of the action of the masticatory apparatus in function.

gnathological (nath-o-loj′i-kal)
Pertaining to gnathodynamics.

gnathology (na-thol′o-je)
The science of the masticatory system, including physiology, functional disturbances, and treatment.

gnathoschisis (na-thos′ki-sis)
Cleft of the jaw. [gnatho- + G. schisis, a cleaving]

gnathostatics (nath-o-stat′iks)
In orthodontic diagnosis, a technical procedure for orienting the dentition to certain cranial landmarks. [gnatho- + G. statikos, causing to stand]

Gnathostoma (na-thos′to-ma)
A genus of spiruroid nematode worms (family Gnathostomatidae) characterized by several rows of cuticular spines about the head and by multiple-host aquatic life cycles; it includes pathogenic parasites of cats, cattle, and swine. [gnatho- + G. stoma, mouth] G. doloresi nematode species found in domestic and wild pigs; human infections (cutaneous larva migrans) reported in Japan. G. hispidum nematode species found in domestic and wild pigs; human infections (cutaneous larva migrans) reported in Japan. G. nipponicum nematode species found in weasels; human infections (cutaneous larva migrans) reported in Japan. G. siamense invalid name for G. spinigerum. G. spinigerum a parasite of cats, dogs, and wild carnivores, it has occasionally been found in humans in the Far East; it is transmitted via copepods and fish; human infection is usually confined to the skin, but several cases have been reported of eye or brain infection with wandering larvae of this species.

gnathostomiasis (nath-o-sto-mi′a-sis)
A migrating edema, or creeping eruption, caused by cutaneous infection by larvae of Gnathostoma spinigerum. SYN: Yangtze edema.

gnoscopine (nos′ko-pen)
An opium alkaloid, C22H23NO7, obtained by racemization of noscapine; an antitussive. SYN: dl-narcotine.

gnosia (no′se-a)
The perceptive faculty enabling one to recognize the form and the nature of persons and things; the faculty of perceiving and recognizing. [G. gnosis, knowledge]

gnotobiology (no′to-bi-ol′o-je)
The study of animals in the absence of contaminating microorganisms; i.e., of “germ-free” animals. [G. gnotos, known, + bios, life, + logos, study]

gnotobiota (no′to-bi-o′ta)
Living colonies or species, assembled from pure isolates. [G. gnotos, known, + Mod. L. biota, fr. G. bios, life]

gnotobiote (no-to-bi′ot)
An individual organism from a group assembled from pure isolates (gnotobiota).

gnotobiotic (no′to-bi-ot′ik)
Denoting germ-free or formerly germ-free organisms in which the composition of any associated microbial flora, if present, is fully defined. [see gnotobiota]

Abbreviation for gonadotropin-releasing hormone.

goal (gol)
In psychology, any object or objective that an organism seeks to attain or achieve. [M.E. gol]

Charles P., French physician, 1813–1877. See G. law.

John D., U.S. anatomist, 1794–1830. See G. fascia.

John T., U.S. pathologist, *1917. See G. tumor.

William H., U.S. dermatologist, 1884–1954. See G. treatment.

Moses, German physician, *1887. See G. test.

Carlo P., 20th century Italian physician. See G. sign.

goggle (gog′gl)
1. A screen cover for the eye. 2. A type of spectacle with auxiliary shields for protecting the eyes. [M.E. gogelen, to squint] plethysmographic g. a specially designed g. to serve as an ophthalmodynamometer while permitting subjective visual and objective ocular changes during transient increased intraocular pressure.

goiter (goy′ter)
A chronic enlargement of the thyroid gland, not due to a neoplasm, occurring endemically in certain localities, especially regions where glaciation occurred and the soil is low in iodine, and sporadically elsewhere. SYN: struma (1) . [Fr. from L. guttur, throat] aberrant g. enlargement of a supernumerary thyroid gland. SYN: struma aberrata. acute g. a g. that develops very rapidly. adenomatous g. an enlargement of the thyroid gland due to the growth of one or more encapsulated adenomas or multiple nonencapsulated colloid nodules within its substance. Basedow g. colloid g. which becomes hyperfunctional after the ingestion of excess iodine, the Jod-Basedow phenomenon. cabbage g. g. due to ingestion of cabbage or other goitrogenic foodstuff. colloid g. a form of g. in which the contents of the follicles increase greatly, causing pressure atrophy of the epithelium so that the gelatinous matter predominates in the tumor. SYN: struma colloides. cystic g. an enlargement in the thyroid region due to the presence of one or more cysts within the gland. diffuse g. g. in which the morbid process involves the whole gland, as opposed to nodular g. or thyroid adenoma. diving g. a freely movable g. that is sometimes above and sometimes below the sternal notch. SYN: wandering g.. endemic g. g., usually of simple type, prevalent in certain regions where dietary intake of iodine is suboptimal. exophthalmic g. any of the various forms of hyperthyroidism in which the thyroid gland is enlarged and exophthalmos is present. familial g. a group of heritable thyroid disorders in which g. is commonly apparent first during childhood; often associated with skeletal and/or mental retardation, and with other signs of hypothyroidism that may develop with age. Various types of familial g. have been identified: 1) iodide transport defect [MIM*274400]; of autosomal recessive inheritance caused by mutation in the sodium iodide symporter gene (SLC5A5) on 19p, in which the gland is unable to concentrate iodide; 2) organification defect [MIM*274500 and *274600], in which the iodination of tyrosine is defective; 3) Pendred syndrome [MIM*274600]; autosomal recessive inheritance caused by mutation in the Pendred syndrome gene (PDS) on 7q; 4) coupling defect, in which cretinism results from defective coupling of iodotyrosines to form iodothyronines [MIM*274700]; 5) iodotyrosine deiodinase defect, in which deiodination of iodotyrosine is defective, considerable glandular loss of these hormonal precursors occurs, and cretinism may be present [MIM*274800]; 6) plasma iodoprotein disorder [MIM*274900], in which an abnormal iodinated serum protein that is insoluble in acidic butanol is present; 7) hereditary hyperthyroidism. fibrous g. a firm hyperplasia of the thyroid and its capsule. follicular g. SYN: parenchymatous g.. lingual g. a tumor of thyroid tissue involving the embryonic rudiment at the base of the tongue. microfollicular g. g. in which the glandular tissue consists of unusually small colloid filled follicles and areas of undifferentiated tissue with indistinct follicle formation. multinodular g. adenomatous g. with several colloid nodules. nontoxic g. g. not accompanied by hyperthyroidism. parenchymatous g. a form of g. in which there is a great increase in the follicles with proliferation of the epithelium. SYN: follicular g.. simple g. thyroid enlargement unaccompanied by constitutional effects, e.g., hypo- or hyperthyroidism, commonly caused by inadequate dietary intake of iodine. substernal g. enlargement of the thyroid gland, chiefly of the lower part of the isthmus, palpable with difficulty or not at all. suffocative g. a g. that by pressure causes extreme dyspnea. thoracic g. enlargement of accessory thyroid tissue in the thorax with or without hyperthyroidism. toxic g. a g. that forms an excessive secretion, causing signs and symptoms of hyperthyroidism. wandering g. SYN: diving g..

goitrogen (goy′tro-jen)
Any substance that induces goiter, e.g., cabbage, rapeseed, etc.

goitrogenic (goy-tro-jen′ik)
Causing goiter.

goitrous (goy′trus)
Denoting or characteristic of a goiter.

gold (Au)
A yellow metallic element, atomic no. 79, atomic wt. 196.96654; 198Au (half-life of 2.694 days) is used in the treatment of certain tumors, for radiation synovectomy, and in imaging. SYN: aurum. cohesive g. nearly pure g. so treated as to be free of adsorbed surface gases and impurities so that it will weld under pressure at room temperature; in dentistry, used as a restorative material placed directly into a prepared cavity and welded by pressure. colloidal radioactive g. SYN: radiogold colloid. mat g. powdered g. formed by electrolytic precipitation, compressed into strips, and sintered. noncohesive g. g. that will not weld because gases adsorb to the surface; some forms may be made cohesive by heat treatment; in dentistry, used as a direct filling material. powdered g. g. formed by atomizing or by chemical precipitation, lightly precondensed, and wrapped with g. foil so as to form pellets. g. sodium thiomalate used in the treatment of rheumatoid arthritis. SYN: sodium aurothiomalate. g. sodium thiosulfate used in the treatment of lupus erythematosus and some cases of rheumatoid arthritis. SYN: sodium aurothiosulfate. g. standard term used to describe a method or procedure that is widely recognized as the best available. [jargon] g. thioglucose SYN: aurothioglucose.

Harry, U.S. pathologist, 1891–1977. See G. hypertension, G. kidney, G. hypertension.

Ross, U.S. radiologist, 1889–1975. See S sign of G..

Maurice, 20th century American physician. See G. syndrome.

golden seal (gold′n sel)
SYN: hydrastis.

Samuel V., Polish neurologist, 1852–1932. See G. disease.

gold foil
Pure gold rolled into extremely thin sheets; used in the restoration of carious or fractured teeth. SEE ALSO: cohesive gold, noncohesive gold.

James H., 20th century Canadian epidemiologist. See G.-Coldman hypothesis.

David E., U.S. physiologist, *1910. See G. equation, G.-Hodgkin-Katz equation.

Henry M., U.S. periodontist, 1911–1980. See G.-Fox knives, under knife.

Hans, Swiss ophthalmologist, 1899–1991. See G. perimeter, G. applanation tonometer.

Johannes K.A.E., German neurologist, 1858–1935. See G. test.

Hyman I., U.S. physician, 1887–1954. See G. toe sign.

Camillo, Italian histologist and Nobel laureate, 1843–1926. See G. apparatus, G. complex, G. corpuscle, G. tendon organ, G. internal reticulum, G. zone, G. cells, under cell, G. osmiobichromate fixative, G. stain, G.-Mazzoni corpuscle, Holmgrén-G. canals, under canal.

golgiokinesis (gol′je-o-ki-ne′sis)
In mitosis, the process of division of the Golgi apparatus and its distribution to the two daughter cells.

Friedrich, Swiss anatomist, 1829–1903. See G. column, nucleus of G., tract of G..

Robert W., U.S. dermatologist, *1923. See G. syndrome.

Albert F., French neurologist and pathologist, 1844–1904. See G. triangle.

gomenol (go′me-nol)
An ethereal oil obtained from a plant, Melaleuca viridiflora; the chief constituent is cineole. It has germicidal action, is free from irritating properties, and has been used in chronic inflammations of the pulmonary mucous membranes and as a vermifuge. SYN: oleogomenol. [Gomen, a locality in New Caledonia, + L. oleum, oil]

gomitoli (go-me′to-le)
Intricately coiled and looped capillary vessels present largely in the upper infundibular stem of the stalk of the pituitary gland; they make up a portion of the pituitary portal circulation. [It. gomitolo, coil]

gommelin (gom′me-lin)
A form of dextrin.

George, Hungarian histochemist in the U.S., 1904–1957. See Grocott-G. methenamine-silver stain, G. nonspecific alkaline phosphatase stain, G. one-step trichrome stain, G. silver impregnation stain, G. chrome alum hematoxylin-phloxine stain. See entries under stain.

Benjamin, English actuary, 1779–1865. See G. hypothesis, G. law.

gomphosis (gom-fo′sis) [TA]
A form of fibrous joint in which a peglike process fits into a hole, as the root of a tooth into the socket in the alveolus. SYN: articulatio dentoalveolaris, dentoalveolar joint, gompholic joint, peg-and-socket articulation, peg-and-socket joint, socket. [G. gomphos, bolt, nail, + -osis, condition]

gonad (go′nad)
An organ that produces sex cells; a testis or an ovary. [Mod. L. fr. G. gone, seed] female g. SYN: ovary. indifferent g. the primordial organ in an embryo before its differentiation into testis or ovary. See indifferent genitalia. male g. SYN: testis. streak g. SYN: gonadal streak.

See gonado-.

gonadal (go-nad′al)
Relating to a gonad.

gonadectomy (go-nad-ek′to-me)
Excision of ovary or testis. SEE ALSO: castration, orchiectomy, ovariectomy. [gonado- + G. ektome, excision]

gonado-, gonad-
The gonads. [G. gone, seed]

gonadoblastoma (go-nad-o-blas-to′ma)
Benign neoplasm composed of germ cells, sex cord, stromal cells; appears in cases of mixed or pure gonadal dysgenesis; usually small (1–3 cm) and partially calcified, but may give rise to malignant germ-cell tumors, most often seminoma/dysgerminoma or embryonal.

gonadocrins (go-nad′o-krinz)
Peptides that stimulate release of both follicle-stimulating hormone and luteinizing hormone from the pituitary; found in ovarian follicular fluid in rats. [gonad + G. krino, to secrete]

gonadoliberin (go′nad-o-lib′er-in)
1. A hypothalamic substance causing the release of gonadotropin. SYN: gonadotropin-releasing factor, gonadotropin-releasing hormone. 2. A decapeptide from pig hypothalami that induces release of both lutropin and follitropin in constant proportions and thus acts as both luliberin and folliberin. SYN: luteinizing hormone/follicle-stimulating hormone-releasing factor. [gonad + L. libero, to free, + -in]


. . . Feedback