A discharge; referring usually to a discharge of the male internal genital organs into the internal urethra; the contents of the organs, including sperm cells, prostatic fluid, and seminal vesicle fluid, mix in the internal urethra with mucus from the bulbourethral glands to form semen. [L. emissio, fr. e- mitto, to send out]
- characteristic e. SYN: characteristic radiation.
- continuous otoacoustic e. a form of evoked otoacoustic e. in which the e. is of the same frequency as the stimulus and persists as long as the stimulus.
- distortion-product otoacoustic e. a form of evoked otoacoustic e. in which a third frequency is produced when two pure tones are used as the stimulus.
- evoked otoacoustic e. a form resulting from acoustic stimulation, as opposed to spontaneous otoacoustic e..
- otoacoustic e. sound emanating from the ear that can be recorded from minute microphones placed in the external auditory canal and is thought to be produced by the outer hair cells in the cochlea. Otoacoustic emissions occur spontaneously and can be evoked by acoustic stimuli; they are more prominent in women than in men and are particularly robust in infants. Indicative of the integrity of the auditory hair cells, they are measured to screen newborns for hearing impairment.
- transient evoked otoacoustic e. a form in which the response is limited in time.

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emis·sion ē-'mish-ən n
1) an act or instance of emitting
2 a) something sent forth by emitting: as (1) electrons discharged from a surface (2) electromagnetic waves radiated by an antenna or a celestial body (3) substances and esp. pollutants discharged into the air (as by a smokestack or an automobile gasoline engine)
b) a discharge of fluid from a living body esp EJACULATE see NOCTURNAL EMISSION

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the flow of semen from the erect penis, usually occurring while the subject is asleep (nocturnal emission).

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emis·sion (e-mishґən) [L. emissio, a sending out] 1. discharge (def. 1). 2. an involuntary discharge of semen.

Medical dictionary. 2011.