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an encircling region or area; by extension, any area with specific characteristics or boundary.
ciliary zone the outer of the two regions into which the anterior surface of the iris is divided by the collarette.
comfort zone an environmental temperature between 13 and 21°C (55 and 70°F) with a humidity of 30 to 55 per cent.
epileptogenic zone an area, stimulation of which may provoke an epileptic seizure.
erogenous zone (erotogenic zone) in psychoanalytic theory, an area of the body through which the libido expresses itself and which is therefore susceptible to erotic excitation upon stimulation; the primary sites are the oral, anal, and genital regions, but the other body orifices, breasts, and skin are also included.
zone of partial preservation in spinal cord injury, an area of only partial damage that may include up to three consecutive spinal segments caudal to the level of the injury.
pupillary zone the inner of the two regions into which the anterior surface of the iris is divided by the collarette.
transition zone (transitional zone) any anatomical region that marks the point at which the constituents of a structure change from one type to another; for example, the circle in the equator of the ocular lens in which epithelial fibers are developed into lens fibers, or the zone (anocutaneous line) that marks the junction of stratified squamous epithelium with columnar epithelium.
the central region of the anterior surface of the iris located between the collarette and the pupillary margin.
Synonym(s): zona pupillaris
The innermost of two annular areas visible on the anterior surface of the iris.See: ciliary zone
See also: zone