Z

Abbreviation for benzyloxycarbonyl (carbobenzoxy-); symbol for an amino acid that is either glutamic acid, glutamine, or a substance that yields glutamic acid on acid hydrolysis of peptides ( e.g., 4-carboxyglutamate or 5-oxoproline); carbobenzoxy; in italics, zusammen.

Z
Z

Abbreviation for atomic number.

z
z

Abbreviation for zepto-.

Zaffaroni
Zaffaroni

Alejandro, Uruguayan-U.S. chemist and biochemist, *1923. See Z. system.

zafirlukast
zafirlukast (za-fir-loo′kast)

A blocker of leukotriene D₄ and E₄ (LTD₄ and LTE₄) components of a slow-reacting substance of anaphylaxis (SRSA); used for the prophylaxis of asthma attacks.

Zaglas
Zaglas

John, 19th century anatomist's assistant in Edinburgh. See Z. ligament.

Zahn
Zahn

Friedrich W., German pathologist, 1845–1904. See Z. infarct, lines of Z., under line, striae of Z., under stria.

Zambusch
Zambusch

Leo von, 20th century German physician. See generalized pustular psoriasis of Z..

zanamivir
zanamivir (zan-am′i-vir)

An agent that inhibits neuraminidase of influenza virus.

Zappert
Zappert

Julius, Austrian physician, 1867–1942. See Z. counting chamber.

Zavanelli
Zavanelli

William, 20th century U.S. obstetrician. See Z. maneuver.

zea
zea (ze′a)

The styles and stigmas of Z. mays (family Gramineae), Indian corn; formerly used as a diuretic and antispasmodic. SYN: cornsilk. [Mod. L. maize]

zearalenone
zearalenone (ze′a-ral-en-on)

One of the resorcylic acid lactones; used in veterinary medicine as an anabolic.

zeatin
zeatin (ze′a-tin)

A cytokinin first isolated from kernels of sweet corn. SYN: maize factor.

zeaxanthin
zeaxanthin (ze′a-zan′thin)

A carotene found in corn, fruits, seeds, and egg yolk; isomeric with xanthophyll. SYN: zeaxanthol. [Mod. L. Zea, Indian corn, fr. L. zea, grain + G. xanthos, yellow, + -in]

zeaxanthol
zeaxanthol (ze-a-za-thol)

SYN: zeaxanthin.

Zeeman
Zeeman

Pieter, Dutch physicist and Nobel laureate, 1865–1943. See Z. effect.

ZEEP
ZEEP

Abbreviation for zero end-expiratory pressure.

zein
zein (ze′in)

A prolamine present in maize; it lacks chiefly the amino acids l-tryptophan and l-lysine and is also low in cysteine content. It is the main storage protein in maize.

Zeis
Zeis

Eduard, Dresden ophthalmologist, 1807–1868. See Z. glands, under gland, zeisian sty.

zeisian zeisian (zis′e-an)

Relating to or described by Eduard Zeis.

Zeitgeist
Zeitgeist (zit′gist)

In psychology, the climate of opinion, conventions of thought, covert influences, and unquestioned assumptions that are implicit in a given culture, the arts, or science at any point in time, and in which the individual operates and thus is influenced. [Ger. zeit, time, + geist, spirit]

Zellweger
Zellweger

Hans U., U.S. pediatrician, 1909–1990. See Z. syndrome.

zelophobia
zelophobia (ze-lo-fo′be-a)

Morbid fear of jealousy. [G. zelos, zeal, + phobos, fear]

zelotypia
zelotypia (ze-lo-tip′e-a)

Excessive zeal, carried to the point of morbidity, in the advocacy of any cause. [G. z.; rivalry, envy, fr. zelos, zeal, + typto, to strike]

Zenker
Zenker

Friedrich A., German pathologist, 1825–1898. See Z. degeneration, Z. diverticulum, Z. fixative, Z. paralysis, formol-Z. fixative.

zeolite
zeolite (ze′o-lit)

A naturally occurring hydrated sodium aluminum silicate, Na₂O&chmpnt;Al₂O₃&chmpnt;(SiO₂)_x&chmpnt;(H₂O)_x, used for softening of hard water by exchanging its Na⁺ for the Ca²⁺ of the water; thus z. is an ion exchanger. Some synthetic ion exchangers are termed synthetic zeolites, although there is no chemical relationship.

zeoscope
zeoscope (ze′o-skop)

A device for determining the alcoholic content of a liquid by ascertaining its exact boiling point. [G. zeo, to boil, + skopeo, to examine]

zepto-
zepto- (z)

Prefix used in the SI and metric systems to signify submultiples of 10⁻²¹.

zero
zero (ze′ro)

1. The figure 0, indicating the absence of magnitude, or nothing. 2. In thermometry, the point from which the figures on the scale start in one or the other direction; in the Celsius and Réaumur scales, z. indicates the freezing point for distilled water; in the Fahrenheit scale, it is 32° below the freezing point of water. [Sp. fr. Ar. sifr, cipher]
absolute z. the lowest possible temperature, that at which the form of translational motion constituting heat is assumed no longer to exist, determined as −273.15°C or 0 kelvin.

zero gravity
zero gravity (ze-ro-grav′i-te)

A physical state existing in space or at a time in flight when the centrifugal thrust of a parabolic glide or turn exactly counteracts the force of gravity.

zeta
zeta (zat′a)

1. The sixth letter of the Greek alphabet, &z.;. 2. In chemistry, denotes the sixth in a series, e.g., the sixth carbon from a functional group. 3. Symbol for electrokinetic potential.

zetacrit
zetacrit (za′ta-krit)

The packed cell volume produced by vertical centrifugation of blood in capillary tubes, allowing controlled compaction and dispersion of red blood cells; read with a hematocrit to produce the zeta sedimentation ratio.

zetaprotein
zetaprotein

SYN: fibronectins.

zeugmatography
zeugmatography (zoog-ma-tog′ra-fe)

Term coined by Lauterbur in 1972 for the joining of a magnetic field and spatially defined radiofrequency field gradients to generate a two-dimensional display of proton density and relaxation times in tissues, the first nuclear magnetic resonance image. [G. zeugma, that which joins together]

zidovudine
zidovudine (zi-do′voo-den)

A thymidine analog that is an inhibitor of in vitro replication of HIV virus, the causative agent of AIDS and ARC, and is used in the management of these diseases. SYN: azidothymidine.

Ziegler
Ziegler

Samuel L., U.S. ophthalmologist, 1861–1926.

Ziehen
Ziehen

Georg T., German psychiatrist, 1862–1950. See Z.-Oppenheim disease.

Ziehl
Ziehl

Franz, German bacteriologist, 1857–1926. See Z. stain, Z.-Neelsen stain.

Ziemann
Ziemann

Hans R.P., German pathologist, 1865–1939. See Z. dots, under dot, Z. stippling.

Zieve
Zieve

Leslie, U.S. physician, *1915. See Z. syndrome.

Zimmerlin
Zimmerlin

Franz, Swiss physician, 1858–1932. See Z. atrophy.

Zimmermann
Zimmermann

Karl W., German histologist, 1861–1935. See Z. corpuscle, Z. granule, Z. elementary particle, polkissen of Z..

Zimmermann
Zimmermann

Wilhelm, German physician, *1910. See Z. reaction, Z. test.

zinc
zinc (Zn) (zingk)

A metallic element, atomic no. 30, atomic wt. 65.39; an essential bioelement; a number of salts of z. are used in medicine; a cofactor in many proteins. [Ger. Zink]
z. acetate an emetic, styptic, and astringent.
z. caprylate a topical antifungal compound.
z. chloride ZnCl₂;formerly used as a caustic for the removal of cutaneous cancers, nevi, etc., and in weak solution in the treatment of gonorrhea and conjunctivitis. SYN: butter of z..
z. gelatin z. oxide, gelatin, glycerin, and purified water; used topically as a protectant.
z. iodide ZnI₂;has been used as an antiseptic and astringent.
medicinal z. peroxide a mixture of z. peroxide, z. carbonate, and z. hydroxide; a topical disinfectant, astringent, and deodorant.
z. oxide ZnO;used as a protective in ointment, as a dusting powder; also used in paint as a substitute for lead carbonate. SYN: flowers of z., z. white.
z. oxide and eugenol used as a base material beneath metallic dental restorations and as a temporary filling material or impression material; setting and hardening result from complex reactions between the powder and the eugenol.
z. permanganate action is similar to that of potassium permanganate, but more astringent; used in urethritis, by injection or douche in a 1:4000 solution.
z. peroxide ZnO₂;a yellowish white powder, insoluble in water and decomposed by acids; used in pharmaceutic preparations. SYN: z. superoxide.
z. phenolsulfonate used as an intestinal antiseptic and locally as an astringent in chronic inflammation of the mucous membranes. SYN: z. sulfocarbolate.
z. phosphide Zn₃P₂;used as a bait poison for the extermination of rats and mice.
z. stearate a z. compound with variable proportions of stearic and palmitic acids; a water-repellent, protective agent used in powders and ointments in the treatment of eczema, acne, and other skin diseases.
z. sulfate used as a local astringent in the treatment of gonorrhea, indolent ulcers, conjunctivitis, and various skin diseases, and internally as an emetic.
z. sulfocarbolate SYN: z. phenolsulfonate.
z. superoxide SYN: z. peroxide.
z. undecylenate, z. undecenoate the z. salt of undecylenic acid; used in the treatment of fungal and other affections of the skin, including psoriasis.
z. white SYN: z. oxide.

zinc-65
zinc-65 (⁶⁵Zn)

A radioactive zinc isotope that decays mainly by K-capture with a half-life of 243.8 days; used as a tracer in studies of zinc metabolism.

zinciferous
zinciferous (zing-kif′er-us)

Containing zinc.

zincoid
zincoid (zing′koyd)

Relating to or resembling zinc. [G. eidos, resemblance]

zingiber
zingiber (zin′ji-ber)

SYN: ginger.

Zinn
Zinn

Johann G., German anatomist, 1727–1759. See Z. artery, Z. vascular circle, Z. corona, Z. ligament, Z. membrane, Z. ring, Z. tendon, Z. zonule.

Zinsser
Zinsser

Hans, U.S. bacteriologist and immunologist, 1878–1940. See Brill-Z. disease.

zirconium
zirconium (Zr) (zir-ko′ne-um)

A metallic element, atomic no. 40, atomic wt. 91.224; widely distributed in nature, but never found in quantity in any one place. [zircon, a mineral, fr. Ar. zarkun, cinnabar, Pers, zargun, goldlike]

zirconium oxide
zirconium oxide

Used as a coating for the skin in dermatologic pharmaceuticals and as a pigment in paints.

zm
zm

Abbreviation for zeptometer.

Zn
Zn

Symbol for zinc.

65Zn
⁶⁵Zn

Abbreviation for zinc-65.

Z<SMCAP>o</SMCAP>2
Zo₂

Symbol for microliters of oxygen taken up per hour by 10⁸ spermatozoa; can vary as a function of temperature.

zo- zo-

See zoo-.

zoanthropic
zoanthropic (zo-an-throp′ik)

Relating to or marked by zoanthropy.

zoanthropy
zoanthropy (zo-an′thro-pe)

A delusion that one is an animal, such as a dog. [G. zoon, animal, + anthropos, man]

zoetic
zoetic (zo-et′ik)

Relating to life. [G. zoe, life]

zoic
zoic (zo′ik)

Relating to living things; having life. [G. zoikos, relating to an animal]

zoite
zoite (zo′it)

SYN: sporozoite. [G. zoon, animal]

Zollinger
Zollinger

Robert M., U.S. surgeon, *1903. See Z.-Ellison syndrome, Z.-Ellison tumor.

Zöllner
Zöllner

Johann F., German physicist, 1834–1882. See Z. lines, under line.

zolpidem
zolpidem (zol′pe-dem)

A sedative/hypnotic drug useful for treating anxiety and resembling benzodiazepines in its pharmacology but differing somewhat in chemical structure. Unlike benzodiazepines, z. lacks prominent anticonvulsant properties, and less tolerance may develop with its use.

zomepirac sodium
zomepirac sodium (zo-me-pir′ak)

An analgesic anti-inflammatory agent, no longer marketed.

zona
zona, pl .zonae (zo′na, zo′ne) [TA]

1. SYN: zone. 2. SYN: herpes zoster. [L. fr. G. zone, a girdle, one of the zones of the sphere]
z. arcuata SYN: arcuate zone.
z. ciliaris SYN: ciliary zone.
z. corona SYN: costal fringe.
z. dermatica a ridge of thickened skin surrounding the protrusion in spina bifida.
z. epithelioserosa the membranous ring, within the z. dermatica, surrounding the protrusion in spina bifida.
z. externa medullae renalis [TA] SYN: outer zone of renal medulla.
z. fasciculata the layer of radially arranged cell cords in the cortical portion of the suprarenal gland, between the z. glomerulosa and z. reticularis; secretes cortisol and dehydroepiandrosterone.
z. glomerulosa the outer layer of the cortex of the suprarenal gland just beneath the capsule; secretes aldosterone.
z. hemorrhoidalis SYN: hemorrhoidal zone.
zonae hypothalamicae [TA] SYN: zones of hypothalamus, under zone.
z. incerta [TA] a flat, obliquely disposed plate of gray matter in the subthalamic region situated between the thalamic fasciculus (tegmental field H₁ of Forel) and the lenticular fasciculus (tegmental field H₂). Medially, cells of this nucleus are adjacent to the prerubral area (tegmental field H) and, laterally, they are continuous with the reticular nucleus of the thalamus. Z. i. is a derivative of the ventral thalamus; it receives afferents from the precentral motor cortex and the cerebellum.
z. interna medullae renalis [TA] SYN: inner zone of renal medulla.
z. lateralis [TA] SYN: lateral zone. See zones of hypothalamus, under zone.
z. medialis [TA] SYN: medial zone. See zones of hypothalamus, under zone.
z. medullovasculosa the fissured segment of the spinal cord that dorsally closes the sac in meningomyelocele.
z. ophthalmica herpes zoster in the distribution of the ophthalmic nerve.
z. orbicularis (articulationis coxae) [TA] fibers of the articular capsule of the hip joint encircling the neck of the femur. SYN: orbicular zone of hip joint, ring ligament, zonular band.
z. pectinata SYN: pectinate zone.
z. pellucida an extracellular coat, rich in glycoprotein, surrounding the oocyte; it contains microvilli of the oocyte and cellular processes of follicular cells and appears homogeneous and translucent under the light microscope. SYN: pellucid zone.
z. perforata SYN: foramina nervosa, under foramen.
z. periventricularis [TA] SYN: periventricular zone. See zones of hypothalamus, under zone.
z. pupillaris SYN: pupillary zone.
z. radiata SYN: z. striata.
z. reticularis the inner layer of the cortex of the adrenal gland, where the cell cords anastomose in a netlike fashion.
z. striata the thickened cell membrane of the ovum in forms, such as certain amphibia, in which it appears radially striated under the light microscope; with the electron microscope the striations can be seen to be microvilli. SYN: membrana striata, striated membrane, z. radiata.
z. tecta SYN: arcuate zone.
z. transitionalis analis [TA] SYN: anal transitional zone.
z. vasculosa SYN: vascular zone.

zonal
zonal (zo′nal)

Relating to a zone.

zonary
zonary (zo′nar-e)

Relating to or having the form of a zone or belt.

zonate
zonate (zo′nat)

Zoned; ringed; having concentric layers of differing texture or pigmentation.

zone
zone (zon) [TA]

A segment; any encircling or beltlike structure, either external or internal, longitudinal or transverse. SEE ALSO: area, band, region, space, spot. SYN: zona (1) [TA] . [L. zona]
abdominal zones SYN: abdominal regions, under region.
anal transitional z. [TA] region of anal canal in which the epithelium changes from the simple columnar epithelium of a mucosa to the stratified squamous epithelium of the anoderm (skin); this region is susceptible to a variety of carcinomas. SYN: zona transitionalis analis [TA] .
androgenic z. 1. SYN: X z. (1) . 2. SYN: fetal reticularis (2) . SYN: fetal adrenal cortex. [Named in the belief (as yet unsubstantiated) that the cells within this z. secrete androgens.]
arcuate z. the inner third of the basilar membrane of the cochlear duct extending from the tympanic lip of the osseous spiral lamina to the outer pillar cell of the spiral organ (of Corti). SYN: zona arcuata, zona tecta.
Barnes z. the lower fourth of the pregnant uterus, attachment of the placenta to any part of which may cause dangerous hemorrhage. SYN: cervical z..
cervical z. SYN: Barnes z..
cervical z. of tooth SYN: neck of tooth.
ciliary z. the outer, wider z. of the anterior surface of the iris, separated from the pupillary z. by the collarette. SYN: zona ciliaris.
comfort z. the temperature range between 28°C and 30°C at which the naked body is able to maintain the heat balance without either shivering or sweating; in the clothed body the range is from 13°C to 21°C.
zones of discontinuity concentric zones of varying optical density in the lens of the eye, as seen in slitlamp biomicroscopy.
dolorogenic z. SYN: trigger point.
entry z. the area of the dorsal funiculus of the spinal cord, medial to the tip of the posterior horn, in which the entering fibers of the posterior nerve root divide into ascending and descending branches.
ependymal z. SYN: ependymal layer.
epileptogenic z. a cortical region that on stimulation reproduces the patient's spontaneous seizure or aura.
equivalence z. in a precipitin reaction, the z. in which neither antibody nor antigen is in excess. SEE ALSO: precipitation. SYN: equivalence point.
erogenous z., erotogenic z. areas of the body, such as genitals and nipples, which elicit sexual arousal when stimulated.
fetal z. SYN: fetal adrenal cortex.
gingival z. that portion of the oral mucosa which surrounds the teeth and is firmly attached to the underlying alveolar bone.
Golgi z. 1. part of the cytoplasm occupied by the Golgi apparatus; 2. in secretory cells of exocrine glands, a z. between the nucleus and the luminal surface.
grenz z. (grents) in histopathology, a narrow layer beneath the epidermis that is not infiltrated or involved in the same way as are the lower layers of the dermis. [Ger. Grenze, borderline, boundary]
Head zones SYN: Head lines, under line.
hemorrhoidal z. the part of the anal canal that contains the rectal venous plexus. SYN: anulus hemorrhoidalis, zona hemorrhoidalis.
zones of hypothalamus [TA] rostrocaudally oriented regions of the hypothalamus characterized by their position and cell groups. The periventricular z. [TA] (zona periventricularis [TA]) is a thin sheet of small neurons located in the wall of the third ventricle. The medial z. [TA] (zona medialis [TA]) lies between the periventricular z. and a rostrocaudal line drawn between the mammillothalamic tract and the postcommissural fornix, and consists of supraoptic, tuberal, and mammillary regions. The lateral z. [TA] (zona lateralis [TA]) is lateral to the medial zones, and contains the tuberal nuclei and the fibers of the medial forebrain bundle. SYN: zonae hypothalamicae [TA] .
inner z. of renal medulla [TA] apical portion of renal pyramids, including renal papilla. SYN: zona interna medullae renalis [TA] .
intermediate z. [TA] SYN: intermediate column.
intermediate z. of iliac crest [TA] the line on the crest of the ilium between the outer and inner lips, for origin of internal oblique muscle. SYN: linea intermedia cristae iliacae [TA] , intermediate line of iliac crest.
interpalpebral z. the exposed area of the cornea and sclera between the lids of the open eye.
intertubular z. the dentinal matrix that lies between zones of peritubular dentin; it is less calcified and contains larger collagen fibers than does peritubular dentin.
isoelectric z. the range of H+ ion concentration (pH) over which isoelectric precipitation occurs.
isopycnic z. the region in density gradient centrifugation having the same density as the buoyant density of the macromolecule.
language z. a large area of the cerebral cortex on the left side (in right-handed persons) considered by some to embrace all the centers of memories and associations connected with language.
latent z. that portion of the cerebral cortex, the stimulation of which produces no movement and a lesion of which produces no symptoms; mainly the more anterior areas of the frontal lobes.
lateral z. [TA] See zones of hypothalamus. SYN: zona lateralis [TA] .
Lissauer marginal z. SYN: dorsolateral fasciculus.
Looser zones SYN: Looser lines, under line.
mantle z. 1. SYN: mantle layer. 2. a layer of small B lymphocytes surrounding the paler-staining germinal centers of lymphoid follicles.
Marchant z. the area on the sphenoid and occipital bones at the base of the skull from which the dura mater is readily detached.
marginal z. 1. A z. between the red and white pulp of the spleen containing numerous macrophages and a rich plexus of sinusoids supplied by white pulp arterioles carrying blood-borne antigens. 2. SYN: marginal layer.
medial z. [TA] See zones of hypothalamus. SYN: zona medialis [TA] .
motor z. that portion of the cerebral cortex, primarily the posterior region of the frontal lobe, near the central sulcus, which when stimulated produces a movement and when injured produces spasticity or paralysis.
neutral z. in dentistry, the potential space between the lips and cheeks on one side and the tongue on the other; natural or artificial teeth in this z. are subject to equal and opposite forces from the surrounding musculature.
nucleolar z. SYN: nucleolar organizer.
Obersteiner-Redlich z. the narrow line along the course of a nerve (or nerve root) where the Schwann cells and connective tissue that support its axons are replaced by glia cells. The z. marks the true boundary between the central and the peripheral nervous system. Usually located at or near the surface of the spinal cord or brainstem, it can extend ( e.g., in the eighth nerve) several millimeters out along the nerve. SYN: Obersteiner-Redlich line.
orbicular z. of hip joint SYN: zona orbicularis (articulationis coxae).
outer z. of renal medulla [TA] basal portion of renal pyramid. SYN: zona externa medullae renalis [TA] .
pectinate z. the outer two-thirds of the basilar membrane of the cochlear duct. SYN: zona pectinata.
pellucid z. SYN: zona pellucida.
peritubular z. the dentinal matrix surrounding the odontoblastic process; it is more highly calcified and contains finer collagen fibers than does the rest of the dentinal matrix.
periventricular z. [TA] See zones of hypothalamus. SYN: zona periventricularis [TA] .
polar z. the region in the vicinity of an electrode applied to the body. SEE ALSO: electrotonus.
protective z. the time in the cardiac cycle, immediately following the vulnerable period, during which a second stimulus will prevent the initiation of ventricular fibrillation by a previous stimulus applied during the vulnerable period, probably by blocking a reentrant pathway.
pupillary z. the central region of the anterior surface of the iris located between the collarette and the pupillary margin. SYN: zona pupillaris.
reflexogenic z. the area or z. where stimulation will elicit a given reflex.
secondary X z. an adrenocortical z., situated in the inner zona fasciculata, that appears upon postpubertal gonadectomy in some male rodents, most notably the mouse; the development of this z. is believed to be stimulated by pituitary gonadotropins.
segmental z. in a young embryo, the thickened dorsal portion of the undifferentiated paraxial mesoderm that becomes metamerically divided to form the mesodermal somites. SYN: segmental plate.
Spitzka marginal z. SYN: dorsolateral fasciculus.
subplasmalemmal dense z. SYN: corneocyte envelope.
sudanophobic z. a z. of cells, at the periphery of the zona fasciculata in the adrenal cortex of the rat, that is not stained by Sudan dyes.
tender zones SYN: Head lines, under line.
thymus-dependent z. SYN: paracortex.
trabecular z. SYN: trabecular tissue of sclera.
transformation z. z. on the cervix at which squamous epithelium and columnar epithelium meet; changes location in response to a woman's hormonal status.
transitional z. 1. the equatorial region of the lens of the eye where the anterior epithelial cells become transformed into lens fibers; 2. that portion of a scleral contact lens between the corneal and scleral sections.
transitional z. of lips [TA] hairless thin skin beginning at the vermillion border of the lips; appears red because of underlying capillary bed.
trigger z. SYN: trigger point.
trophotropic z. of Hess an area in the hypothalamus concerned with rewarding bodily sensations.
vascular z. an area in the external acoustic meatus where a number of minute blood vessels enter from the mastoid bone. SYN: spongy spot, zona vasculosa.
vermilion z., vermilion transitional z. SYN: vermilion border.
Weil basal z. SYN: Weil basal layer.
Wernicke z. SYN: Wernicke center.
z. 1, 2, 3, 4 of West in pulmonary physiology, defines the levels in a vertical lung according to the relationships of alveolar gas pressure, capillary blood pressure, and pulmonary venous pressure.
X z. 1. a transient adrenocortical z. present in some rodents at birth, most notably in mice, situated between the zona reticularis and the adrenal medulla; it degenerates in males with the secretion at puberty and in females during their first pregnancy; it slowly enlarges in unmated females after puberty and does not degenerate until middle age; the X z. appears to secrete no hormone; SYN: androgenic z. (1) . 2. misnomer for the fetal adrenal cortex of primates. SYN: fetal reticularis (3) .

zonesthesia
zonesthesia (zon-es-the′ze-a)

A sensation as if a cord were drawn around the body, constricting it. SYN: girdle sensation, strangalesthesia. [G. zone, girdle, + aisthesis, sensation]

zoning
zoning (zon′ing)

The occurrence of a stronger reaction in a lesser amount of suspected serum, observed sometimes in serologic tests used in the diagnosis of syphilis, and probably the result of high antibody titer.

zonography
zonography (zo-nog′ra-fe)

A form of tomography with a relatively thick plane of focus; especially used in renal radiography. [zone + G. grapho, to write]

zonoskeleton
zonoskeleton (zo′no-skel′e-ton)

The proximal skeletal segments of the limbs, i.e., scapula, clavicle, hip bone. [L. zona, zone, + skeleton]

zonula
zonula, pl .zonulae (zo′nu-la, zon′u-; -le)

SYN: zonule. [L. dim. of zona, zone]
z. adherens a beltlike desmosomal attachment between columnar epithelial cells, upon which filaments attach. SYN: intermediate junction.
z. ciliaris [TA] SYN: ciliary zonule.
z. occludens tight junctions formed by the fusion of integral proteins of the lateral cell membranes of adjacent epithelial cells, limiting transepithelial permeability. SYN: impermeable junction, tight junction.

zonular
zonular (zo′nu-lar, zon′u-)

Relating to a zonula.

zonule
zonule (zo′nul, zon′ul)

A small zone. SYN: zonula.
ciliary z. [TA] a series of delicate meridional fibers arising from the inner surface of the orbiculus ciliaris that run in bundles between, and in a very thin layer over, the ciliary processes; at the inner border of the corona, the fibers diverge into two groups that are attached to the capsule on the anterior and posterior surfaces of the lens close to the equator; the spaces between these two layers of fibers are filled with aqueous humor. SYN: zonula ciliaris [TA] , apparatus suspensorius lentis, suspensory ligament of lens, Zinn z..
Zinn z. SYN: ciliary z..

zonulitis
zonulitis (zo-nu-li′tis)

Assumed inflammation of the zonule of Zinn, or suspensory ligament of the lens of the eye. [zonule + G. -itis, inflammation]

zonulolysis
zonulolysis, zonulysis (zo′nu-lol′i-sis, -li′sis)

Dissolution of the zonula ciliaris by enzymes (α-chymotrypsin) to facilitate surgical removal of a cataract. SYN: Barraquer method. [zonule + G. lysis, dissolution]

zoo- zoo-, zo-

Animal, animal life. [G. zoon]

zooanthroponosis
zooanthroponosis (zo′o-an′thro-po-no′sis)

A zoonosis normally maintained by humans but that can be transmitted to other vertebrates ( e.g., amebiasis to dogs, tuberculosis). Cf.:anthropozoonosis, amphixenosis. [zoo- + G. anthropos, man, + nosos, disease]

zooblast
zooblast (zo′-o-blast)

An animal cell. [zoo- + G. blastos, germ]

zoochrome
zoochrome (zo′o-krom)

A naturally occurring animal pigment; includes human pigments.

zoodermic
zoodermic (zo-o-der′mik)

Relating to the skin of an animal. [zoo- + G. derma, skin]

zooerastia
zooerastia (zo′o-e-ras′te-a)

SYN: zoophilia. [zoo- + G. erastes, lover]

zoofulvin
zoofulvin (zo′o-ful′vin)

A yellow pigment obtained from the feathers of certain birds.

zoogenesis
zoogenesis (zo-o-jen′e-sis)

The doctrine of animal production or generation. [zoo- + G. genesis, origin]

zoogeography
zoogeography (zo′o-je-og′ra-fe)

The geography of animals; the study of the distribution of animals on the earth's surface.

zooglea
zooglea (zo-og′le-a, zo′o-gle′a)

In bacteriology, an old term for a mass of bacteria held together by a clear gelatinous substance. [zoo- + G. glia, glue]

zoogonous
zoogonous (zo-oj′o-nus)

SYN: viviparous.

zoogony
zoogony (zo-oj′o-ne)

SYN: viviparity.

zoograft
zoograft (zo′o-graft)

A graft of tissue from an animal to a human. SYN: animal graft, zooplastic graft.

zoografting
zoografting (zo-o-graft′ing)

SYN: zooplasty.

zooid
zooid (zo′oyd)

1. Resembling an animal; an organism or object with an animal-like appearance. 2. An animal cell capable of independent existence or movement, as the ovum or a spermatozoon, or the segment of a tapeworm. 3. An individual of a colonial invertebrate, such as a coral. [G. zoodes, fr. zoon, animal, + eidos, resemblance]

zoolagnia
zoolagnia (zo-o-lag′ne-a)

An older term for sexual attraction toward animals. [zoo- + G. lagneia, lust]

zoolite
zoolite, zoolith (zo′o-lit, zo-o-lith)

A petrified animal. [zoo- + G. lithos, stone]

zoologist
zoologist (zo-ol′o-jist)

One who specializes in zoology.

zoology
zoology (zo-ol′o-je)

The branch of biology that deals with animals. [zoo- + G. logos, study]

zoom
zoom (zoom)

The action of a varifocal lens system in a camera or microscope that maintains an object in focus while approaching it or receding from it; this effect may be obtained by moving two or more of the lens components at rates bearing a linear relation to one another.

zoomania
zoomania (zo-o-ma′ne-a)

An excessive, abnormal love of animals. [zoo- + G. mania, frenzy]

zoomaric acid
zoomaric acid (zo′o-mer-ik)

SYN: palmitoleic acid.

Zoomastigina
Zoomastigina (zo′o-mas-ti-ji′na)

SYN: Zoomastigophorea. [zoo- + G. mastix, whip]

Zoomastigophorasida
Zoomastigophorasida (zo′o-mas-ti-go-fo-ras′i-da)

SYN: Zoomastigophorea.

Zoomastigophorea
Zoomastigophorea (zo′o-mas-ti-go-fo′re-a)

A class of flagellates (superclass Mastigophora) within the phylum Sarcomastigophora (flagellate and ameboid protozoans), of animal-like as opposed to plantlike characteristics. Chromatophores are absent; one to many flagella are found, although they may be absent in ameboid forms; sexuality is known in some groups. It includes many human parasites such as the trypanosomes and trichomonads, as well as a number of other parasitic and symbiotic forms. SYN: Zoomastigina, Zoomastigophorasida. [zoo- + G. mastix, whip, + phoros, bearing]

zoonosis
zoonosis (zo-o-no′sis)

An infection or infestation shared in nature by humans and other animals. SEE ALSO: anthropozoonosis, cyclozoonosis, metazoonosis, saprozoonosis, zooanthroponosis. [zoo- + G. nosos, disease]
direct z. a z. transmitted between humans and other animals from an infected to a susceptible host by contact, by airborne droplets or droplet nuclei, or by some vehicle of transmission; the agent requires a single vertebrate host for completion of its life cycle and does not develop or show significant change during transmission; may include anthropozoonoses (rabies), zooanthroponoses (amebiasis), and amphixenoses (certain streptococcoses).

zoonotic
zoonotic (zo′o-not′ik)

Relating to a zoonosis.

zooparasite
zooparasite (zo-o-par′a-sit)

An animal parasite; an animal existing as a parasite.

zoopathology
zoopathology (zo-o-pa-thol′o-je)

The study or science of diseases of the lower animals.

zoophagous
zoophagous (zo-of′a-gus)

SYN: carnivorous. [G. zoophagos, fr. zoon, animal, + phagein, to eat]

zoophile
zoophile (zo′o-fil)

1. A lover of animals; especially one more fond of animals than of humans. 2. One opposed to any animal experimentation; an antivivisectionist. [zoo- + G. philos, fond]

zoophilia
zoophilia (zo-o-fil′e-a)

A paraphilia in which sexual arousal and orgasm are facilitated by engaging in sexual activities with animals. SYN: bestiality, zooerastia.

zoophilic
zoophilic (zo-o-fil′ik)

1. Relating to or displaying zoophilism. 2. Animal-seeking or animal-preferring; denoting preference of a parasite for an animal host over a human. [zoo- + G. philos, fond, loving]

zoophilism
zoophilism (zo-of′i-lizm)

Fondness for animals, especially an extravagant fondness for them.
erotic z. the deriving of sexual pleasure by patting or stroking animals. SEE ALSO: zoophilia, bestiality.

zoophobia
zoophobia (zo-o-fo′be-a)

Morbid fear of animals. [zoo- + G. phobos, fear]

zoophyte
zoophyte (zo′o-fit)

An animal that resembles a plant, such as the sponges or sea anenomes. [zoo- + G. phyton, plant]

zooplasty
zooplasty (zo′o-plas-te)

Grafting of tissue from an animal to a human. SYN: zoografting.

zoosadism
zoosadism (zo-o-sa′dizm)

Sexual pleasure from cruelty to animals.

zoosmosis
zoosmosis (zo-os-mo′sis)

The process of osmosis in living tissues. [G. zoos, living, + osmosis]

zoospermia
zoospermia (zo-o-sper′me-a)

The presence of live spermatozoa in the ejaculated semen. [G. zoon, living, + sperma, seed, + -ia]

zoosterol
zoosterol (zo′o-ster′ol)

An animal sterol.

zootechnics
zootechnics (zo-o-tek′niks)

The art of managing domestic or captive animals, including handling, breeding, and keeping. [zoo- + G. techne, art]

zootic
zootic (zo-ot′ik)

Pertaining to animals other than humans.

zootoxin
zootoxin (zo-otok′sin)

A substance, resembling the bacterial toxins in its antigenic properties, found in the fluids of certain animals; e.g., in snake venom, the secretions of poisonous insects, eel blood. SYN: animal toxin.

zootrophic
zootrophic (zo-o-trof′ik)

Relating to or serving for the nutrition of the lower animals. [zoo- + Gr. trophe, nourishment]

zorubicin
zorubicin (zo-roo-bi-sin)

Semisynthetic derivative of daunorubicin; also similar to doxorubicin. Like those agents, z. exerts significant myocardial toxicity. Used as an antineoplastic in breast cancer.

zoster
zoster (zos′ter)

SYN: herpes z.. [G. z., a girdle]
geniculate z. (jen-i′kyu-lat zos′ter) SYN: herpes z. oticus.

zosteriform
zosteriform (zos-ter′i-form)

SYN: zosteroid.

zosteroid
zosteroid (zos′ter-oyd)

Resembling herpes zoster. SYN: zosteriform. [zoster + G. eidos, resemblance]

zoxazolamine
zoxazolamine (zok-sa-zo′la-men)

A centrally acting skeletal muscle relaxant that is no longer used because of its hepatic toxicity.

Z-plasty
Z-plasty

Technique to elongate a contracted scar or to rotate tension 90°; the middle line of a Z-shaped incision is made along the line of greatest tension or contraction, and triangular flaps are raised on opposite sides of the two ends and transposed.

Zr
Zr

Symbol for zirconium.

Zsigmondy
Zsigmondy

Richard A., Austro-German chemist and Nobel laureate, 1865–1929. See Z. test, brownian-Z. movement.

ZSR
ZSR

Abbreviation for zeta sedimentation ratio.

Zuckerkandl
Zuckerkandl

Emil, Austrian anatomist, 1849–1910. See Z. bodies, under body, Z. convolution, Z. fascia, organs of Z., under organ.

zusammen
zusammen (Z) (zu-sam′men)

1. SYN: cis- (4) . 2. A form of geometric isomerism with regard to carbon-carbon double bonds in which all four moieties attached to the carbons are different. If the substituents with the higher ranking (based on established rules) are on the same side of the double bond, Z is used. See entgegen. [Ger. together]

zwieback
zwieback (zwi′bak)

Sweetened bread that has been baked twice, preferred for infant feeding during teething. [Ger. twice-baked]

Zwischenferment
Zwischenferment (tsvish′en-fer-ment′)

SYN: glucose-6-phosphate dehydrogenase. [Ger. zwischen, between, + Ferment, fermentation]

zwittergents
zwittergents (tsvit′er-jents)

Detergents that are zwitterionic; often used as surfactants and in the release of proteins from biomembranes. SYN: zwitterionic detergent. [zwitterion + detergent]

zwitterionic
zwitterionic (tsvit′er-i-on′ik)

Denoting a substance with the properties of a zwitterion; e.g., at pH value of 6.11, alanine is z..

zwitterions
zwitterions (tsvit′er-i-onz)

SYN: dipolar ions, under ion. SEE ALSO: zwitter hypothesis. [Ger. Zwitter, hermaphrodite, mongrel + ion]

zyg- zyg-

See zygo-.

zygal
zygal (zi′gal)

Relating to or shaped like a zygon or yoke; H-shaped.

zygapophysial
zygapophysial, zygapophyseal (zi′ga-po-fiz′e-al, zi-ga-pof′i-se′al)

Relating to a zygapophysis or articular process of a vertebra.

zygapophysis
zygapophysis, pl .zygapophyses (zi′ga-pof′i-sis, -sez)

SYN: articular process, articular process. [G. zygon, yoke, + apophysis, offshoot]
z. inferior [TA] SYN: inferior articular process.
z. superior [TA] SYN: superior articular process.

zygion
zygion (zig′e-on)

In cephalometrics and craniometrics, the most lateral point of the zygomatic arch. [G. a later form of zygon, yoke]

zygo- zygo-, zyg-

A yoke, a joining. [G. zygon, yoke, zygosis, a joining]

zygoma
zygoma (zi-go′ma)

1. SYN: zygomatic bone. 2. SYN: zygomatic arch. [G. a bar, bolt, the os jugale, fr. zygon, yoke]

zygomatic
zygomatic (zi′go-mat′ik)

Relating to the z. bone.

zygomatico- zygomatico-

Zygomatic; relating usually to the zygomatic bone. See zygo-. [G. zygoma]

zygomaticoauricular
zygomaticoauricular (zi′go-mat′i-ko-aw-rik′u-lar)

Relating to the zygomatic bone and the auricle.

zygomaticoauricularis
zygomaticoauricularis (zi′go-mat′i-ko-aw-rik′u-lar′is)

SYN: auricularis anterior (muscle).

zygomaticofacial
zygomaticofacial (zi′go-mat′i-ko-fa′shal)

Relating to the zygomatic bone and the face.

zygomaticofrontal
zygomaticofrontal (zi′go-mat′i-ko-fron′tal)

Relating to the zygomatic and frontal bones.

zygomaticomaxillary
zygomaticomaxillary (zi′go-mat′i-ko-mak′si-lar-e)

Relating to the zygomatic bone and the maxilla.

zygomatico-orbital
zygomatico-orbital (zi′go-mat′i-ko-or′bi-tal)

Relating to the zygomatic bone and the orbit.

zygomaticosphenoid
zygomaticosphenoid (zi′go-mat′i-ko-sfe′noyd)

Relating to the zygomatic and sphenoid bones.

zygomaticotemporal
zygomaticotemporal (zi′go-mat′i-ko-tem′po-ral)

Relating to the zygomatic and temporal bones.

zygomaxillare
zygomaxillare (zi′go-mak-si-la′re)

A craniometric point located externally at the lowest extent of the zygomaticomaxillary suture. SYN: key ridge, zygomaxillary point.

zygomaxillary
zygomaxillary (zi-go-mak′si-lar-e)

Relating to the zygomatic bone and the maxilla.

Zygomycetes
Zygomycetes (zi′go-mi-se′tez)

A class of fungi characterized by sexual reproduction resulting in the formation of a zygospore, and asexual reproduction by means of nonmotile spores called sporangiospores or conidia. SYN: Phycomycetes. [zygo- + G. mykes (myket-), fungus]

zygomycosis
zygomycosis (zi′go-mi-ko′sis)

A broad term that includes mucormycosis and entamophthoramycosis; usually applied when culture is not available and the clinical entity is unclear. SYN: phycomycetosis, phycomycosis.

zygon
zygon (zi′gon)

The short crossbar connecting the branches of a zygal fissure. [G. crossbar, yoke]

zygonema
zygonema (zi-g-o-ne′ma)

SYN: zygotene. [zygo- + G. nema, thread]

zygopodium
zygopodium (zi-go-po′de-um)

The distal intermediate segment of the limb skeleton, i.e., radius and ulna, tibia and fibula. [zygo- + G. podion, small foot]

zygosis
zygosis (zi-go′sis)

True conjugation or sexual union of two unicellular organisms, consisting essentially in the fusion of the nuclei of the two cells. [G. a joining]

zygosity
zygosity (zi-gos′i-te)

The nature of the zygotes from which individuals are derived; e.g., whether by separation of the division of one zygote (monozygotic), in which case they will be genetically identical, or from two separate fertilized ova (dizygotic).

zygosperm
zygosperm (zi′go-sperm)

SYN: zygospore. [zygo- + G. sperma, seed]

zygospore
zygospore (zi′go-spor)

Among the Phycomycetes, a thick-walled sexual spore arising from fusion of two morphologically identical structures, generally hyphal tips, bearing nuclei of opposite mating types (gametangia). SYN: zygosperm.

zygosyndactyly
zygosyndactyly (zi-go-sin-dak′til-e)

Complete or incomplete webbing of the fingers or toes. [zygo- + syndactyly]

zygote
zygote (zi′got)

1. The diploid cell resulting from union of a sperm and an ovum. Cf.:conceptus. 2. The individual that develops from a fertilized ovum. [G. zygotos, yoked]

zygotene
zygotene (zi′go-ten)

The stage of prophase in meiosis in which precise point for point pairing of homologous chromosomes begins. SYN: zygonema. [zygo- + G. tainia (L. taenia), band]

zygotic
zygotic (zi-got′ik)

Pertaining to a zygote, or to zygosis.

zygotoblast
zygotoblast (zi-go′to-blast)

SYN: sporozoite. [G. zygotos, yoked, + blastos, germ]

zygotomere
zygotomere (zi-go′to-mer)

SYN: sporoblast. [G. zygotos, yoked, + meros, part]

zym- zym-

See zymo-.

zymase
zymase (zi′mas)

1. Obsolete term for a mixture of enzymes. 2. Specifically, the intracellular enzymes of yeast that promotes alcoholic fermentation.

zymo- zymo-, zym-

Fermentation, enzymes. [G. zyme, leaven]

zymodeme
zymodeme (zi′mo-dem)

An isoenzyme pattern, as identified by isoenzyme electrophoresis. [zymo- + G. demos, populace]

zymogen
zymogen (zi′mo-jen)

SYN: proenzyme.

zymogenesis
zymogenesis (zi-mo-jen′e-sis)

Transformation of a proenzyme (zymogen) into an active enzyme. [zymo- + G. genesis, production]

zymogenic
zymogenic (zi-mo-jen′ik)

1. Relating to a zymogen or to zymogenesis. SYN: zymogenous. 2. Causing fermentation.

zymogenous
zymogenous (zi-moj′e-nus)

SYN: zymogenic (1) .

zymogram
zymogram (zi′mo-gram)

Strips of paper, gels, etc., in which the locations of enzymes, separated electrophoretically or by other means, are demonstrated by histochemical methods. [zymo- + G. gramma, something written]

zymosan
zymosan (zi′mo-san)

A carbohydrate (glucose polymer) obtained from the walls of yeast cells that interferes with complement.

zymoscope
zymoscope (zi′mo-skop)

An instrument measuring CO₂ evolved and, therefore, the fermenting power of yeast. [zymo- + G. skopeo, to view]

zymosterol
zymosterol (zi-mos′ter-ol)

An intermediate in the biosynthesis of cholesterol from lanosterol.

zyxin
zyxin (ziks′in)

A cytoplasmic protein found in a number of distinct types of adherens junctions; it may play a role in the organization of membrane-cytoskeletal attachments.

ZZ
ZZ

See ZZ genotype.