H zone

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(zon) [L. zona, fr. Gr. zone, a girdle],


1. An area or belt.
2. A lobe of an organ or a gland.

anal transition zone

Abbreviation: ATZ
The histologic junction between the anal squamous epithelium and the rectal columnar epithelium.

border zone

The partially damaged part of an organ that is found between tissue that is severely injured by an infarct and nearby tissue that is still well supplied with blood, oxygen, and nutrients.

cell-free zone

In dentistry, an area below the odontoblastic layer of the dental pulp that has relatively few cells.
Synonym: zone of Weil

cell-rich zone

The area of increased cell frequency between the cell-free zone and the central pulp of the tooth.

chemoreceptor trigger zone

Abbreviation: CTZ
A zone in the medulla that is sensitive to certain chemical stimuli. Stimulation of this zone may produce nausea.

ciliary zone

The peripheral annular sector of the anterior surface of the iris of the eye. The ciliary zone is separated from the inner, more narrow annulus, the pupillary zone, of the iris by a wavy boundary, the collarette. These regions are used in automated iris recognition technology.

cold zone

In a hazardous materials incident, an unexposed area where rescue personnel wait for assignments and the command post is located, which is safe from any potential contamination.

comfort zone

The range of temperature, humidity, and, when applicable, solar radiation and wind in which an individual doing work at a specified rate and in a certain specified garment is comfortable.

epileptogenic zone

Any area of the brain that after stimulation produces an epileptic seizure.

erogenous zone

An area of the body that may produce erotic sensations when stimulated. These areas include, but are not limited to, the breasts, lips, genital and anal regions, buttocks, and sometimes the special senses that cause sexual excitation, such as the sense of smell or taste.

H zone

H band.

hot zone

In a hazardous materials incident or biohazard laboratory, the area where the hazardous materials are located. This area cannot be entered without protective equipment, special permission, and specialized training.

hypnogenic zone

Any area of the body that, when pressed on, induces hypnosis.
Synonym: hypnogenic spot

Looser zones

See: Looser zones

lung zone

A hypothetical region of the lung defined by the relationship between the degree of alveolar ventilation and pulmonary blood flow (perfusion). Three lung zones have been identified: I, ventilation exceeds perfusion; II, ventilation and perfusion are equal; and III, perfusion exceeds ventilation. Zone I is found in the upper lung field, where gravity impedes perfusion, and zone III in the inferior portion of the lung, where gravity assists perfusion.

pellucid zone

Zona pellucida.

peripheral zone

Abbreviation: PZ
The lateral border of the prostate gland. Most prostate cancers begin here. Synonym: peripheral zone of the prostate

peripheral zone of the prostate

Peripheral zone.

pupillary zone

The innermost of two annular areas visible on the anterior surface of the iris.
See: ciliary zone

zone of stasis

The area of skin beneath the coagulated surface of a burn in which blood flow is diminished and tissue fluid collects. This region of a burn may become necrotic if it becomes infected or fails to receive adequate blood flow.

transition zone

1. Tissue that includes two or more cell types linking two distinct regions of an organ.
Squamocolumnar junction.

transitional zone

The area of the lens of the eye where the epithelial capsule cells change into lens fibers.

trigger zone

Trigger point.

warm zone

In a hazardous materials incident, the area between the hot zone and the cold zone, where decontamination occurs. Only specialized personnel who are appropriately dressed are permitted in this location.

zone of Weil

Cell-free zone.
Medical Dictionary, © 2009 Farlex and Partners

H zone

the lightish area in the middle of a muscle SARCOMERE where MYOSIN and ACTIN filaments do not overlap.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005