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Medical Dictionary


symplast (sim′plast)
A multinucleated cell that has formed by fusion of separate cells. [sym- + G. plastos, formed]

sympodia (sim-po′de-a)
Condition characterized by union of the feet. SEE ALSO: sirenomelia, sympus. [sym- + G. pous, foot]

symport (sim′port)
Coupled transport of two different molecules or ions through a membrane in the same direction by a common carrier mechanism (symporter). Cf.:antiport, uniport. [sym- + L. porto, to carry]

symporter (sim-port′er)
The protein responsible for mediating symport.

symptom (simp′tom)
Any morbid phenomenon or departure from the normal in structure, function, or sensation, experienced by the patient and indicative of disease. SEE ALSO: phenomenon (1) , reflex (1) , sign (1) , syndrome. [G. symptoma] abstinence symptoms SYN: withdrawal symptoms. accessory s. a s. that usually but not always accompanies a certain disease, as distinguished from a pathognomonic s.. SYN: assident s., concomitant s.. accidental s. any morbid phenomenon coincidentally occurring in the course of a disease, but having no relation with it. assident s. SYN: accessory s.. Baumès s. pain behind the sternum in angina pectoris. Bolognini s. a feeling of crepitation on gradually increasing pressure on the abdomen in cases of measles. cardinal s. the primary or major s. of diagnostic importance. concomitant s. SYN: accessory s.. constitutional s. a s. indicating a systemic effect of a disease; e.g., weight loss. deficiency s. manifestation of a lack, in varying degrees, of some substance ( e.g., hormone, enzyme, vitamin) necessary for normal structure and/or function of an organism. Demarquay sign absence of elevation of the larynx during deglutition, said to indicate syphilitic induration of the trachea. Epstein s. See Epstein sign. equivocal s. a s. that points definitely to no special disease, being associated with any one of a number of morbid states, or whose presence is uncertain or indefinite. first rank symptoms (FRS) SYN: Schneider first rank symptoms. Fischer s. SYN: Fischer sign. Gordon s. SYN: tonic reflex. incarceration s. SYN: Dietl crisis. induced s. a s. excited by a drug, exercise, or other means, often intentionally for diagnostic purposes. local s. a s. of limited extent, caused by disease of a particular organ or part. localizing s. a s. indicating clearly the seat of the morbid process. Macewen s. SYN: Macewen sign. negative s. one of the deficit symptoms of schizophrenia that follow from diminished volition and executive function including inertia, anergia, lack of involvement with the environment, poverty of thought, social withdrawal, and blunted affect. objective s. a s. that is evident to the observer. pathognomonic s. a s. that, when present, definitely points to the presence of a certain disease. positive s. one of the acute or florid symptoms of schizophrenia, including hallucinations, delusions, thought disorder, loose associations, ambivalence, or affective lability. Pratt s. rarely used term for rigidity in the muscles of an injured limb, which precedes the occurrence of gangrene. presenting s. the complaint offered by the patient as the main reason for seeking medical care; usually synonymous with chief complaint. rainbow s. SYN: glaucomatous halo (2) . reflex s. a disturbance of sensation or function in an organ or part more or less remote from the morbid condition giving rise to it; e.g., muscle spasm due to joint inflammation. SYN: sympathetic s.. Schneider first rank symptoms those symptoms that, when present, indicate that the diagnosis of schizophrenia is likely, provided that organic or toxic etiology is ruled out: delusion of control, thought broadcasting, thought withdrawal, thought insertion, hearing one's thoughts spoken aloud, auditory hallucinations that comment on one's behavior, and auditory hallucinations in which two voices carry on a conversation. SYN: first rank symptoms, schneiderian first rank symptoms. schneiderian first rank symptoms SYN: Schneider first rank symptoms. Sklowsky s. the rupture of a varicella vesicle on very slight pressure with the finger, greater pressure being necessary to break the vesicles of smallpox, herpes, or other affections. subjective s. a s. apparent only to the patient. sympathetic s. SYN: reflex s.. Trendelenburg s. a waddling gait in paresis of the gluteal muscles, as in progressive muscular dystrophy. Uhthoff s. a transient temperature-dependent numbness, weakness, or loss of vision. Conduction stops in any nerve if the temperature gets too high. In a damaged nerve, e.g., by demyelinization, this shutdown temperature is lowered, and may approach normal body temperature. Transient neurological dysfunction may then appear with a hot shower, exercise, or fever. SYN: Uhthoff syndrome. Wartenberg s. 1. flexion of the thumb when the patient attempts to flex the four fingers against resistance, a “pyramid sign”. 2. intense pruritus of the tip of the nose and nostrils in cases of cerebral tumor; withdrawal symptoms a group of morbid symptoms, including excitability and irritability, occurring in an addict who is deprived of the accustomed dose of the addicting agent. SYN: abstinence symptoms.

symptomatic (simp-to-mat′ik)
Indicative; relating to or constituting the aggregate of symptoms of a disease.

symptomatology (simp′to-ma-tol′o-je)
1. The science of the symptoms of disease, their production, and the indications they furnish. 2. The aggregate of symptoms of a disease. [symptom + G. logos, study]

symptomatolytic (simp′to-mat-o-lit′ik)
Removing symptoms. SYN: symptomolytic. [symptom + G. lytikos, dissolving]

symptomolytic (sim-to-mo-lit′ik)
SYN: symptomatolytic.

symptosis (sim-to′sis)
A localized or general wasting of the body. [G. a falling together, collapse, fr. syn, together, + ptosis, a falling]

sympus (sim′pus)
An individual in which the legs and feet are united in the midline. [G. sympous, fr. sym- + pous, foot] s. apus a sirenomelus without feet. s. dipus a sirenomelus with both feet more or less distinct. s. monopus a sirenomelus with but one foot externally visible.

Parker, U.S. surgeon, 1860–1933. See S. tractor.

Together, with, joined; appears as sym- before b, p, ph, or m; corresponds to L. con-. [G. syn, with, together]

synadelphus (sin-a-del′fus)
Conjoined twins with single head, partially united trunk, and four upper and four lower limbs. See conjoined twins, under twin. [syn- + G. adelphos, brother]

synanamorph (sin-an′a-morf)
The same fungal species growing in a different form.

synanastomosis (sin′an-as-to-mo′sis)
An anastomosis between several blood vessels.

synandrogenic (sin′an-dro-jen′ik)
Relating to any agent or condition that enhances the effects of androgens.

synanthem, synanthema (si-nan′them, sin′an-the′ma)
An exanthem consisting of several different forms of eruption. [G. syn- antheo, to blossom together]

synaphoceptors (si-naf-o-sep′terz)
Receptors stimulated by direct contact. [G. synaphe, contact, + L. recipio, to receive]

synapse, pl .synapses (sin′aps, si-naps′; si-nap′sez)
The functional membrane-to-membrane contact of the nerve cell with another nerve cell, an effector (muscle, gland) cell, or a sensory receptor cell. The s. subserves the transmission of nerve impulses, commonly from a variably large (1–12 μm), generally knob-shaped or club-shaped axon terminal (the presynaptic element) to the circumscript patch of the receiving cell's plasma membrane (the postsynaptic element) on which the s. occurs. In most cases the impulse is transmitted by means of a chemical transmitter substance (such as acetylcholine, γ-aminobutyric acid, dopamine, norepinephrine) released into a synaptic cleft (15–50 nm wide) that separates the presynaptic from the postsynaptic membrane; the transmitter is stored in quantal form in synaptic vesicles: round or ellipsoid, membrane-bound vacuoles (10–50 nm in diameter) in the presynaptic element. In other synapses transmission takes place by direct propagation of the bioelectrical potential from the presynaptic to the postsynaptic membrane; in such electrotonic synapses (“gap junctions”), the synaptic cleft is no more than about 2 nm wide. In most cases, synaptic transmission takes place in only one direction (“dynamic polarity” of the s.), but in some synapses synaptic vesicles occur on both sides of the synaptic cleft, suggesting the possibility of reciprocal chemical transmission. [syn- + G. hapto, to clasp] axoaxonic s. the synaptic junction between an axon terminal of one neuron and either the initial axon segment or an axon terminal of another nerve cell. axodendritic s. the synaptic contact between an axon terminal of one nerve cell and a dendrite of another nerve cell. axosomatic s. the synaptic junction of an axon terminal of one nerve cell to the cell body of another nerve cell. SYN: pericorpuscular s.. electrotonic s. SYN: gap junction. SEE ALSO: s.. pericorpuscular s. SYN: axosomatic s..

synapsin I (si-nap′sin)
A fibrous phosphoprotein that links synaptic vesicles together in the axon terminal; synapsin I is a substrate for certain kinases; phosphorylation of synapsin I allows release of neurotransmitters.

synapsis (si-nap′sis)
The point-for-point pairing of homologous chromosomes during the prophase of meiosis. SYN: synaptic phase. [G. a connection, junction]

synaptic (si-nap′tik)
1. Relating to a synapse. 2. Relating to synapsis.

synaptology (sin′ap-tol′o-je)
Study of the synapse.

synaptophysin (si-nap′to-fi′sin)
An integral membrane protein found in many types of active neurons; believed to form a hexamer that forms an ion channel and is involved in the uptake of neurotransmitters; s. is found in the membrane only after stimulation of the neurons.

synaptosome (si-nap′to-som)
Membrane-bound sac containing synaptic vesicles that breaks away from axon terminals when brain tissue is homogenized under controlled conditions; such particles can be separated from other subcellular particles by differential and density gradient centrifugation. [synapse + G. soma, body]

synarthrodia (sin′ar-thro′de-a)
SYN: fibrous joint.

synarthrodial (sin-ar-thro′de-al)
Relating to synarthrosis; denoting an articulation without a joint cavity.

synarthrophysis (sin-ar-thro-fi′sis)
The process of ankylosis. [syn- + G. arthron, joint, + physis, growth]

synarthrosis, pl .synarthroses (sin′ar-thro′sis, -sez) [TA]
An immovable or nearly immovable union of rigid components of the skeletal system, including fibrous joints, cartilaginous joints, and bony unions (synostoses). See articulation. [G. fr. syn, together, + arthrosis, articulation]

syncanthus (sin-kan′thus)
Adhesion of the eyeball to orbital structures. [syn- + L. canthus, wheel]

syncaryon (sin-kar′e-on)
SYN: synkaryon.

syncephalus (sin-sef′a-lus)
Conjoined twins having a single head with two bodies. See conjoined twins, under twin. Cf.:craniopagus, janiceps. SYN: monocephalus, monocranius. [syn- + G. kephale, head] s. asymmetros SYN: janiceps asymmetrus.

syncephaly (sin-sef′a-le)
The condition exhibited by a syncephalus. SYN: prozygosis.

syncheilia (sin-ki′le-a)
A more or less complete adhesion of the lips; atresia of the mouth. SYN: synchilia. [syn- + G. cheilos, lip]

syncheiria (sin-ki′re-a)
A form of dyscheiria in which the subject refers a stimulus applied to one side of the body to both sides. SYN: synchiria. [syn- + G. cheir, hand]

SYN: syncheilia.


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