|| ANATOMY || DISEASES || DRUGS || HEALTH TOPICS || USA HEALTH STATS || CHINA HEALTH STATS || GENOMICS || LABORATORY MICE || LUPUS ||
Medical Dictionary banner
Medical Dictionary - Dictionary of Medicine and Human Biology


Medical Dictionary


A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


σ, upper case Σ
  • sigma, 18th letter of the Greek alphabet
  • factor in prokaryotic RNA initiation
  • reflection coefficient
  • standard deviation
  • summation of a series
  • surface tension
  • wavenumber
S
  • entropy
  • human antigen (hemagglutinogen) related genetically to the MNSs blood group
  • percentage saturation of hemoglobin
  • sacral vertebra (S1–S5)
  • serine
  • siemens
  • signa, used to introduce the signature in writing a prescription
  • smooth (bacterial colonies)
  • spherical, spherical lens
  • stereochemical designation in the Cahn-Ingold-Prelog system
  • subject
  • substrate in the Michaelis-Menton mechanism
  • sulfur
  • svedberg unit
s
  • selection coefficient
  • sedimentation coefficient
S-A
sinoatrial

S-adenosyl-l-homocysteine (a-den′o-sil-ho-mo-sis′te-en)
The compound formed by the demethylation of S-adenosyl-l-methionine.

S-adenosyl-l-methionine (SAM, AdoMet) (a-den′o-sil-me-thi′o-nen)
Condensation product of adenosine and l-methionine involving replacement of the &cbond;OPO3H2 of adenylic acid by &cbond;S+(CH3)CH2CH2CH(NH3+)CO2 of methionine; a sulfonium compound bearing a methyl group that is transferred in transmethylation reactions. SEE ALSO: methionine adenosyltransferase, aka active methionine.

S-nitrosohemoglobin (ni-tro′so-he′moglo′bin)
A compound formed by the binding of nitric oxide with hemoglobin; release and uptake of the nitric oxide group produce changes in vascular resistance and blood flow, which assist in oxygen homeostasis.

S100
An acidic, calcium-binding protein characterized by its partial solubility in saturated ammonium sulfate; stains for S. are used in the differential diagnosis of melanomas, which are commonly positive for S..

35S
Symbol for sulfur-35.

S1
Symbol for first heart sound.

S
Symbol for entropy.

S2
Symbol for second heart sound.

S3
Symbol for third heart sound.

S4
Symbol for fourth heart sound.

S7
SYN: summation gallop.

Sf
Symbol for flotation constant.

s
Abbreviation of L. sinister, left; L. semis, half; second; as a subscript, denotes steady state.

s
Abbreviation for L. sine, without.

S-A
Abbreviation for sinuatrial.

SA
Abbreviation for sacroanterior position.

sabadilla (sab-a-dil′a)
The seed of Schoenocaulon officinale (family Liliaceae), a plant of the shores of the Gulf of Mexico and Caribbean Sea; it yields cevadine, veratridine, and several other alkaloids; has been used externally as a parasiticide. SYN: cevadilla. [Sp. cevadilla, ult. fr. L. cibus, food]

Sabin
Albert B., Polish-U.S. virologist, 1906–1993. See S. vaccine, S.-Feldman dye test.

Sabouraud
Raymond J.A., French dermatologist, 1864–1938. See S. agar, S. pastils, under pastil, S.-Noiré instrument.

sabulous (sab′u-lus)
Sandy; gritty. [L. sabulosus, fr. sabulum, coarse sand]

saburra (sa-bur′a)
Foulness of the stomach or mouth resulting from decomposed food. [L. sand]

saburral (sa-bur′al)
Relating to saburra.

sac (ˈsak)
  • pouch or bursa, aka saccus. SEE ALSO: sacculus.
  • encysted abscess at the root of a tooth
  • the capsule of a tumor, or envelope of a cyst. [L. saccus, a bag]
  • abdominal s. the part of the embryonic celom that becomes the abdominal cavity.
  • air s.: alveolar s..
  • allantoic s.: the dilated distal portion of the allantois; it forms part of the placenta in many mammals.
  • alveolar s.: terminal dilation of the alveolar ducts that give rise to alveoli in the lung; a small air chamber in the pulmonary tissue from which the pulmonary alveoli project like bays and into which an alveolar duct opens; sacculus alveolaris
  • in birds, air-containing extensions of bronchi that connect with bone cavities, aka air s..
  • amnionic s.: amnion.
  • aneurysmal s.: the dilated wall of an artery in a saccular aneurysm.
  • aortic s.: in mammalian embryos, the endothelially lined dilation just distal to the truncus arteriosus; it is the primordial vascular channel from which the aortic arch/arteries arise and is homologous to the ventral aorta of gill-bearing vertebrates.
  • chorionic s.: chorion.
  • conjunctival s.: the space bound by the conjunctival membrane between the palpebral and bulbar conjunctiva, into which the lacrimal fluid is secreted; it is a closed space when eye is closed; when eye is open, the s. is open anteriorly via the palpebral fissure (between the eyelids), aka saccus conjunctivalis .
  • cupular blind s.: cupular cecum of the cochlear duct.
  • dental s.: the outer investment of mesenchymal tissue surrounding a developing tooth; involved in formation of the root and periodental ligament. SEE ALSO: dental follicle.
  • endolymphatic s.: the dilated blind extremity of the endolymphatic duct, which lies external to the dura on the posterior aspect of the petrous part of the temporal bone, aka saccus endolymphaticus , Böttcher space, Cotunnius space, sacculus endolymphaticus.
  • gestational s.: cystic structure of early pregnancy that represents the amnionic s., fluid, and placenta.
  • heart s.: pericardium.
  • hernial s.: the protruding envelope of peritoneum in a hernia.
  • Hilton s.: laryngeal saccule.
  • lacrimal s.: the dilated upper portion of the nasolacrimal duct into which the two lacrimal canaliculi empty, aka saccus lacrimalis , dacryocyst, sacculus lacrimalis, tear s..
  • lesser peritoneal s.: omental bursa.
  • lymph sacs: the earliest lymphatic vessels formed in the embryo.
  • nasal sacs: the deepened nasal pits that develop into the definitive nasal cavities.
  • omental s.: omental bursa.
  • preputial s.: the space between the prepuce and the glans penis.
  • pudendal s.: a pear-shaped encapsulated collection of connective tissue and fat in each labium majus, aka Broca pouch.
  • tear s.: lacrimal s..
  • tooth s.: a capsule that encloses the developing tooth.
  • vestibular blind s.: vestibular cecum of the cochlear duct.
  • vitelline s.: yolk s..
  • yolk s.: in vertebrates with telolecithal eggs; the highly vascular layer of splanchnopleure surrounding the yolk of an embryo
  • in humans and other mammals, the s. of extraembryonic membrane that is located ventral to the embryonic disk and, after formation of the gut tube, is connected to the midgut; by the second month of development, this connection has become the narrow yolk stalk; the yolk s. is the first hematopoietic organ of the embryo, and its vitelline circulation plays an important role in the early embryonic circulation; the s. is also the site of origin of the primordial germ cells. aka umbilical vesicle, vesicula umbilicalis, vitelline s..
saccade (sa-kad′)
Rapid eye movement to redirect the line of sight. [Fr. s., sudden check of a horse]

saccadic (sa-kad′ik)
Jerky. See s. movement.

saccate (sak′at)
Relating to a sac. [L. saccus, sac]

sacchar-
See saccharo-.

saccharase (sak′a-ras)
SYN: β-fructofuranosidase.

saccharate (sak′a-rat)
A salt or ester of saccharic acid.

saccharephidrosis (sak-ar-ef-i-dro′sis)
The presence of sugar in the sweat. [sacchar- + G. ephidrosis, a slight perspiration]

sacchari-
See saccharo-.

saccharic (sa-kar′ik)
Relating to sugar.

saccharic acid (sak′a-rik)
Term used to denote the class of dicarboxy sugar acids.

saccharides (sak′a-ridz)
S. are classified as mono-, di-, tri-, and polysaccharides according to the number of monosaccharide groups composing them. See carbohydrates.

sacchariferous (sak′a-rif′er-us)
Producing sugar.

saccharification (sa-kar′i-fi-ka′shun)
The process of saccharifying.

saccharify (sa-kar′i-fi)
To convert starch or cellulose or other polysaccharides into sugar. [sacchari- + L. facio, to make]

saccharimeter (sak-a-rim′e-ter)
An instrument for determining the amount of sugar in a solution; it may be a polarimeter, a hygrometer, or a container in which the solution is fermented and the amount estimated by the volume of CO2 produced. SYN: saccharometer. [(sacchari- + G. metron, measure]

saccharin (sak′a-rin)
In dilute aqueous solution it is 300–500 times sweeter than sucrose; used as a noncaloric sweetening agent (sugar substitute); s. sodium and s. calcium have the same use. SYN: benzosulfimide.

saccharine (sak′a-ren, -rin, -rin)
Relating to sugar; sweet.

saccharo-, sacchar-, sacchari-
Combining forms denoting sugar (saccharide). [G. sakcharon, sugar]

saccharogen amylase (sak′a-ro-jen)
SYN: β-amylase.

saccharolytic (sak′a-ro-lit′ik)
Capable of hydrolyzing or otherwise breaking down a sugar molecule. [saccharo- + G. lysis, loosening]

saccharometabolic (sak′a-ro-met′a-bol′ik)
Relating to saccharometabolism.

saccharometabolism (sak-a-ro-me-tab′o-lizm)
Metabolism of sugar; the process of utilization of sugar in cells.

saccharometer (sak-a-rom′e-ter)
SYN: saccharimeter.

Saccharomyces (sak′a-ro-mi′sez)
A genus of budding yeasts (family Saccharomycetaceae); an ascomycete. S. cerevisiae is used to produce brewer's yeast and ethanol. S. cerevisiae is a very rare pathogen in humans. [saccharo- + G. mykes, fungus]

Saccharomycetaceae (sak′a-ro-mi-se-ta′se-e)
The family of yeasts; that group of fungi comprising the ascomycetes which possess a predominantly unicellular thallus, reproduce asexually by budding, transverse division, or both, and produce ascospores in an ascus, originating from a zygote or pathogenetically from a single somatic cell. The term yeastlike fungus is often applied to fungi that are not known to form ascospores, but otherwise possess the characteristics of yeasts; such forms are properly placed with the Fungi Imperfecti unless methods of sexual reproduction are known; e.g., Cryptococcus neoformans.

Saccharomycetales (sak′a-ro-mi′se-ta′lez)
SYN: Endomycetales.

saccharopine (sak-ar′o-pen)
A derivative of α-ketoglutarate and l-lysine that is an intermediate in l-lysine catabolism; elevated in cases of saccharopinuria. s. dehydrogenase two enzymes that are used in the pathway of l-lysine catabolism; the first isoform catalyzes the reversible conversion of l-lysine, α-ketoglutarate, and NADH to s. and NAD+; the other isoform reversibly catalyzes to conversion of s. and NAD+ to l-glutamate, NADH, and l-α-aminoadipate δ-semialdehyde. A deficiency of one of these isoforms is associated with familial hyperlysinemia and saccharopinuria.

saccharopinuria (sak-ar′o-pen-oor-e-a)
Elevated levels of saccharopine in the urine; associated with a variant of familial hyperlysinuria.

saccharose (sak′a-ros)
SYN: sucrose.

saccharum (sak′a-rum)
SYN: sucrose. [Mod. L. fr. G. sakcharon] s. canadense SYN: maple sugar. s. lactis SYN: lactose.

sacciform (sak′si-form)
Pouched; sac-shaped. SYN: saccular, sacculated. [L. saccus, sack, + forma, form]

saccular (sak′u-lar)
SYN: sacciform.

sacculated (sak′u-la′ted)
SYN: sacciform.

sacculation (sak′u-la′shun)
1. A structure formed by a group of sacs. 2. The formation of a sac or pouch. s. of colon SYN: haustra of colon, under haustrum.

saccule (sak′ul)
1. [TA] The smaller of the two membranous sacs in the vestibule of the labyrinth, lying in the spherical recess; it is connected with the cochlear duct by a very short tube, the ductus reuniens, and with the utriculus by the beginning of the ductus endolymphaticus and the ductus utriculosaccularis that joins it. 2. The immense bag-shaped structure formed by peptidoglycans as part of the cell wall of certain microorganisms. SYN: sacculus [TA] , sacculus proprius, sacculus vestibuli. [L. sacculus] laryngeal s. [TA] a small diverticulum provided with mucous glands extending upward from the ventricle of the larynx between the vestibular fold and the lamina of the thyroid cartilage; it is a vestigial structure, being a much larger structure interdigitating with the neck musculature in some of the great apes, where it serves as a resonating chamber. SYN: sacculus laryngis [TA] , appendix ventriculi laryngis, Hilton sac, laryngeal pouch, s. of larynx. s. of larynx SYN: laryngeal s..

sacculocochlear (sak′u-lo-kok′le-ar)
Relating to the sacculus and the membranous cochlea.

sacculus, pl .sacculi (sak′u-lus, -li) [TA]
SYN: saccule. [L. dim. of saccus, sac] s. alveolaris, pl .sacculi alveolares [TA] SYN: alveolar sac (1) . s. communis SYN: utricle. s. endolymphaticus SYN: endolymphatic sac. s. lacrimalis SYN: lacrimal sac. s. laryngis [TA] SYN: laryngeal saccule. s. proprius SYN: saccule. s. vestibuli SYN: saccule.

saccus, pl .sacci (sak′us, sak′si) [TA]
SYN: sac (1) . [L. a bag, sack] s. conjunctivalis [TA] SYN: conjunctival sac. s. endolymphaticus [TA] SYN: endolymphatic sac. s. lacrimalis [TA] SYN: lacrimal sac. s. reuniens SYN: sinus venosus. s. vaginalis an embryonic peritoneal fossa indicating the site where the processus vaginalis peritonei extends through the anterior abdominal wall during descent of the testis.

Sachs
Bernard, U.S. neurologist, 1858–1944. See Tay-S. disease.

Sachs
Hans, German bacteriologist, 1877–1945. See S.-Georgi test.

Sachs
Maurice D., U.S. radiologist, *1909. See Hill-S. lesion.

Sacks
Benjamin, U.S. physician, 1896–1939. See Libman-S. endocarditis, Libman-S. syndrome.

sacr-
See sacro-.

sacrad (sa′krad)
In the direction of the sacrum. [sacr- + L. ad, to]




A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

. . . Feedback