Copy of `Dorland's Medical Dictionary`

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Dorland's Medical Dictionary Category: Health and Medicine > Medical Dictionary Date & country: 31/12/2010, USA Words: 39128

helicine arteries of penis
helicine arteries arising from the vessels of the penis, whose engorgement causes erection of the organ.

helicine arteries of uterus
the exceedingly twisted and curled terminal branches of the uterine artery in the uterine muscle.

helicis major muscle
origin, spine of helix; insertion, anterior border of helix; innervation, auriculotemporal and posterior auricular nerves; action, tenses skin of auditory canal.

helicis minor muscle
origin, anterior rim of helix; insertion, concha; innervation, temporal and posterior auricular nerves.

Helicobacter pylori
(hel″ĭ-ko-bak´ter pi-lo´ri) a gram-negative spiral bacterium that causes gastritis and peptic ulcers in humans; a history of H. pylori infection is associated with carcinoma of the stomach.

helicoid
(hel´ĭ-koid) spiral (def. 2).

helicopod gait
a gait in which the feet describe half circles, as in some conversion disorders.

helicotrema
(hel″ĭ-ko-tre´mә) the passage that connects the scala tympani and the scala vestibuli at the apex of the cochlea. Helicotrema, shown in the interior of the right bony labyrinth.

helium
(He) (he´le-әm) a chemical element, atomic number 2, atomic weight 4.003. It is a chemically inert element that is odorless, tasteless, and noncombustible.

helium-oxygen therapy
administration of a mixture of the two gases, usually 70 or 80 per cent helium and 20 or 30 per cent oxygen, for treatment of airway obstruction associated with bronchospasm or bronchial asthma. The He-O2 mixture is about one third the density of air, which reduces turbulent flow and the effort a person has to exert in order to...

helix
(he´liks) pl. he´lices, helixes a winding structure; see also coil and spiral. the superior and posterior free margin of the pinna of the ear. α-helix , alpha helix the complex structural arrangement of parts of protein molecules in which a single polype...

Heller operation
esophagocardiomyotomy.

Heller-Döhle disease
(hel´әr dur´lә) syphilitic aortitis.

Hellin's law
(hel´inz) one in about 89 pregnancies ends in the birth of twins; one in 892, or 7921, of triplets; one in 893, or 704,969, of quadruplets.

HELLP syndrome
hemolysis, elevated liver enzymes, and low platelet count occurring in association with preeclampsia.

helmet cell
schistocyte.

helminth
(hel´minth) a parasitic worm, such as a nematode or a fluke.

helminthiasis
(hel″min-thi´ә-sis) infection with worms.

helminthology
(hel″min-thol´ә-je) the scientific study of parasitic worms.

helminthoma
(hel″min-tho´mә) a tumor caused by a parasitic worm.

heloma
(he-lo´mә) corn. heloma durum hard corn; see corn. heloma molle soft corn; see corn.

helotomy
(he-lot´ә-me) excision or paring of a corn or callus.

helper cells
helper T cells T lymphocytes of the CD4 cell group that cooperate with B lymphocytes for the synthesis of antibody to many antigens; they play an integral role in immunoregulation.

helper virus
one that aids in the development of a defective virus by supplying or restoring the activity of the viral gene or enabling it to form a protein coat.

Helweg-Larsen syndrome
(hel´veg-lahr´sәn) an autosomal dominant syndrome consisting of anhidrosis present from birth and labyrinthitis later in life.

hemacytometer
(he″mә-si-tom´ә-tәr) a device used for manual blood counts, consisting of a counting chamber of uniform depth that is covered by a ruled cover glass so that the region under each ruled square contains a known volume of the diluted specimen. Called also hemocytometer.

hemadsorption
(he″mad-zorp´shәn) the adherence of red blood cells to other cells, particles, or surfaces. adj., hemadsor´bent., adj.

hemadsorption test
an in vitro test for detecting hemagglutinating viruses based on the adherence of red blood cells to cells of the infected tissue in the presence of hemagglutinin.

hemadsorption virus, type 1
(HA1) former name for human parainfluenza virus 3.

hemadsorption virus, type 2
(HA2) former name for human parainfluenza virus 1.

hemadynamometry
(he″mә-di″nә-mom´ә-tre) measurement of blood pressure.

hemagglutination
(he″mә-gloo″tĭ-na´shәn) agglutination of erythrocytes.

hemagglutinin
(he″mә-gloo´tĭ-nin) an antibody that causes agglutination of erythrocytes. cold hemagglutinin one that acts optimally at temperatures near 4° C. warm hemagglutinin one that acts optimally at temperatures near 37° C.

hemal
(he´mәl) ventral to the spinal axis, where the heart and great vessels are located. hemic. pertaining to the blood vessels; see vascular.

hemal nodes
nodes with a rich content of erythrocytes within sinuses, found near large blood vessels along the ventral side of the vertebrae and near the spleen and kidneys in various mammals, especially ruminants, having functions probably like those of the spleen; their presence in humans is doubtful.

hemanalysis
(he″mә-nal´ә-sis) analysis of the blood.

hemangiectasis
(he-man″je-ek´tә-sis) dilatation of blood vessels.

hemangioameloblastoma
(he-man″je-o-ә-mel″o-blas-to´mә) a highly vascular ameloblastoma.

hemangioblast
(he-man´je-o-blast) a mesodermal cell that gives rise to both vascular endothelium and hemocytoblasts.

hemangioblastoma
(he-man″je-o-blas-to´mә) a benign blood vessel tumor of the cerebellum, spinal cord, or retina, consisting of proliferated blood vessel cells and angioblasts. Those arising in the cerebellum (cerebellar hemangioblastoma) may be cystic and associated with von hippel-lindau disease. Called also angioblastoma. ...

hemangioendothelioblastoma
(he-man″je-o-en″do-the″le-o-blas-to´mә) a hemangioendothelioma with embryonic elements of mesenchymal origin.

hemangioendothelioma
(he-man″je-o-en″do-the″le-o´mә) a rare, well-differentiated endothelial tumor with an appearance between that of a hemangioma and a sarcoma; sometimes considered to be identical to a hemangiosarcoma.

hemangiofibroma
(he-man″je-o-fi-bro´mә) a hemangioma containing fibrous tissue.

hemangioma
(he-man″je-o´mә) a common type of congenital vascular malformation or benign tumor made up of newly formed blood vessels clustered together; it may be present at birth or appear a little later. The most common type appears as a network of small blood-filled capillaries near the surface of the skin, for...

hemangiomatosis
(he-man″je-o-mә-to´sis) the presence of multiple hemangiomas.

hemangiopericytoma
(he-man″je-o-per″ĭ-si-to´mә) a tumor composed of spindle cells with a rich vascular network, which apparently arises from pericytes.

hemangiosarcoma
(he-man″je-o-sahr-ko´mә) a malignant tumor of vascular tissue; called also angiosarcoma.

hemapheresis
(he″mә-fә-re´sis) apheresis.

hemarthros
(he-mahr´thros) hemarthrosis.

hemarthrosis
(he″mahr-thro´sis) blood in a joint cavity; called also hemarthros.

hematemesis
(he″mә-tem´ә-sis) the vomiting of blood. A fresh hemorrhage will yield bright red blood, but blood that has been in the stomach for a time will be acted on by stomach acids and be thick and dark colored. Common causes of hematemesis include peptic ulcer, gastritis, esophageal varices or lesions, and ca...

hematencephalon
(he″mat-) ( hem″at-en-sef´ә-lon) effusion of blood into the brain.

hemathermous
(he″mә-thur´mәs) homeothermic.

hematic
(he-mat´ik) hemic. hematinic.

hematidrosis
(he″mә-) (hem″ә-tĭ-dro´sis) excretion of bloody sweat.

hematin
(he´mә-tin) the hydroxide of heme; it stimulates the synthesis of globin, inhibits the synthesis of porphyrin, and is a component of cytochromes and peroxidases; it is also used as a reagent. hemin (def. 1).

hematinemia
(he″mә-) (hem″ә-tĭ-ne´me-ә) the presence of heme in the blood.

hematinic
(he″mә-tin´ik) improving the quality of the blood. an agent that does this, increasing the hemoglobin level and the number of erythrocytes; examples are iron preparations, liver extract, and the members of the vitamin B complex.

hematinuria
(he″mә-tĭ-nu´re-ә) the presence of hematin in the urine, seen in hemoglobinuria.

hematobilia
(he″mә-to-) ( hem″ә-to-bil´e-ә) hemobilia.

hematoblast
(he´mә-to-) (he-mat´o-blast″) blast cell.

hematocele
(he´mә-to-) (hem´ә-to-sēl″) an effusion of blood into a cavity, especially into the tunica vaginalis testis.

hematochezia
(he″mә-to-) (hem″ә-to-ke´zhә) defecation in which feces are bloody.

hematochromatosis
(he″mә-to-) (hem″ә-to-kro″mә-to´sis) hemochromatosis.

hematochyluria
(he″mә-to-) (hem″ә-to-ki-lu´re-ә) the discharge of blood and chyle in the urine., as seen in filariasis.

hematocolpometra
(he″mә-to-) (hem″ә-to-kol″po-me´trә) accumulation of menstrual blood in the vagina and uterus.

hematocolpos
(he″mә-to-) (hem″ә-to-kol´pәs) accumulation of menstrual blood in the vagina.

hematocrit
(he-mat´ә-krit) the volume percentage of erythrocytes (packed red blood cells) in whole blood, determined by centrifuging a blood sample to separate the cellular elements from the plasma. The results of the test indicate the ratio of cell volume to plasma volume. Called also packed-cell volume. the p...

hematocyst
(he´mә-to-) (he-mat´o-sist″) effusion of blood into the bladder or in a cyst.

hematogenesis
(he″mә-to-) (hem″ә-to-jen´ә-sis) hematopoiesis.

hematogenic
(he″mә-to-) (he-mat″o-jen´ik) hematopoietic. hematogenous.

hematogenous
(he″mә-toj´ә-nәs) produced by or derived from the blood; disseminated through the bloodstream or by the circulation.

hematogenous pigment
blood pigment.

hematogenous tuberculosis
that carried through the bloodstream from the primary site of infection to other organs.

hematoid
(he´mә-toid) like blood.

hematoidin
(he-mә-toid´in) a hematogenous pigment apparently identical to bilirubin but formed in the tissues from hemoglobin, particularly under conditions of reduced oxygen tension.

hematologist
(he″mә-tol´ә-jist) a specialist in hematology.

hematology
(he″mә-tol´ә-je) the branch of medical science dealing with the blood and blood-forming tissues, including morphology, physiology, and pathology. adj., hematolog´ic., adj.

hematolymphangioma
(he″mә-to-) (hem″ә-to-lim″fan-je-o´mә) a tumor composed of blood and lymph vessels.

hematolysis
(he″mә-tol´ә-sis) hemolysis.

hematoma
(he″mә-to´mә) a localized collection of extravasated blood, usually clotted, in an organ, space, or tissue; bruises and black eyes are familiar forms that are seldom serious. Hematomas can occur almost anywhere on the body, and are almost always present with a fracture; in minor injuries the bloo...

hematomediastinum
(he″mә-to-) (hem″ә-to-me″de-әs-ti´nәm) effusion of blood into the mediastinum.

hematometra
(he″mә-to-) (hem″ә-to-me´trә) an accumulation of menstrual blood in the uterus.

hematometry
(he″mә-tom´ә-tre) measurement of various parameters of the blood, such as the complete blood count.

hematomyelia
(he″mә-to-) (hem″ә-to-mi-e´le-ә) hemorrhage into the substance of the spinal cord.

hematomyelitis
(he″mә-to-) (hem″ә-to-mi″ә-li´tis) acute myelitis with bloody effusion into the spinal cord.

hematomyelopore
(he″mә-to-) (hem″ә-to-mi´әl-o-por″) formation of canals in the spinal cord due to hemorrhage.

hematonephrosis
(he″mә-to-) (hem″ә-to-nә-fro´sis) the presence of blood in the renal pelvis; called also hemonephrosis.

hematopathology
(he″mә-to-) (hem″ә-to-pә-thol´ә-je) hemopathology.

hematophagous
(he″mә-) (hem″ә-tof´ә-gәs) subsisting on blood.

hematopoiesis
(he″mә-to-) (hem″ә-to-poi-e´sis) the formation and development of blood cells. In the embryo and fetus it takes place in a variety of sites including the liver, spleen, thymus, lymph nodes, and bone marrow; from birth throughout the rest of life it is mainly in the bone marrow wi...

hematopoietic
(he″mә-to-) ( hem″ә-to-poi-et´ik) pertaining to hematopoiesis (formation of blood cells). promoting hematopoiesis. an agent that promotes hematopoiesis.

hematopoietic growth factors
a group of substances with the ability to support hematopoietic colony formation in vitro, including erythropoietin, interleukin-3, and colony-stimulating factors. All except erythropoietin stimulate mature cells, have overlapping capabilities to affect progenitor cells of several blood cell lines, and also affect cells o...

hematopoietic progenitor cells
hematopoietic stem cells pluripotentblood cell progenitors that represent a slightly later stage than blast cells. They have the capacity for replication and differentiation and give rise to precursors of various blood cell lines, including the proerythroblast and myeloblast; neither of these cell types can self-replicate, and t...

hematopoietic system
the tissues concerned in production of the blood, including the bone marrow, liver, lymph nodes, spleen, and thymus. See also hematopoiesis.

hematoporphyrin
(he″mә-to-) (hem″ә-to-por´fә-rin) a hematogenous pigment that is an iron-free derivative of heme, a product of the decomposition of hemoglobin.

hematosalpinx
(he″mә-to-) (hem″ә-to-sal´pinks) an accumulation of blood in the fallopian tube.

hematospermatocele
(he″mә-to-) (hem″ә-to-spәr-mat´o-sēl) a spermatocele containing blood.

hematospermia
(he″mә-to-) (hem″ә-to-spur´me-ә) hemospermia.

hematosteon
(he″mә-) ( hem″ә-tos´te-on) hemorrhage into the medullary cavity of a bone.