Macula

A macula is a small spot. A macula on the skin is a small flat spot while the macula in the eye is a small spot where vision is keenest in the retina. The macula of the retina, the light-sensitive layer of tissue at the back of the eye, is the best known macula. It is in the center of the retina. As we read, light is focused onto our macula where millions of cells change the light into nerve signals that tell the brain what we are seeing. This is called central vision thanks to which we are able to read, drive, and perform other activities that require fine, sharp, straight-ahead vision. If the macula begins to degenerate, central visions begins to go.

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1. [TA] A circumscribed flat area, up to 1.0 cm in diameter, perceptibly different in color from the surrounding tissue. 2. A small, discolored patch or spot on the skin, neither elevated above nor depressed below the skin's surface. SEE ALSO: spot. 3. The neuroepithelial sensory receptors of the utricle and saccule of the vestibular labyrinth collectively. SYN: maculae utriculosaccularis [TA]. SEE ALSO: neuroepithelium of m.. SYN: macule, spot (1). [L. a spot]

- maculae acusticae m. of saccule, m. of utricle.

- m. adherens SYN: desmosome.

- m. albida, pl.maculae albidae gray-white or white, rounded or irregularly shaped, slightly opaque patches or spots that are sometimes observed postmortem in the epicardium, especially in middle-aged or older persons; they result from fibrous thickening, and sometimes hyalinization, of the epicardium; similar lesions may also occur in the visceral layer of the peritoneum. SYN: m. lactea, m. tendinea, tache blanche, tache laiteuse (2), tendinous spot, white spot.

- m. atrophica an atrophic glistening white spot on the skin.

- m. cerulea a bluish stain on the skin caused by the bites of fleas or lice, especially pediculosis pubis. SYN: blue spot (1).

- m. communicans SYN: gap junction.

- m. communis the thickened area in the medial wall of the auditory vesicle that later subdivides to form the maculae of the sacculus and utriculus as well as the cristae of the ampullae of the semicircular ducts.

- m. corneae a moderately dense opacity of the cornea. SYN: corneal spot.

- m. cribrosa, pl.maculae cribrosae [TA] one of three areas on the wall of the vestibule of the labyrinth, marked by numerous foramina giving passage to nerve filaments supplying portions of the membranous labyrinth; m. cribrosa inferior [TA], located in the posterior bony ampulla for passage of posterior ampullary nerve fibers; m. cribrosa media [TA], area near the base of the cochlea through which the saccular nerve fibers pass; m. cribrosa superior [TA], perforated area above the elliptical recess for passage of the utriculoampullary nerve fibers; m. cribrosa quarta, a name sometimes applied to the opening for the cochlear nerve.

- m. cribrosa quarta a name sometimes applied to the opening for the cochlear nerve.

- m. densa a closely packed group of densely staining cells in the distal tubular epithelium of a nephron, in direct apposition to the juxtaglomerular cells; they may function as either chemoreceptors or as baroreceptors feeding information to the juxtaglomerular cells.

- false m. an extrafoveal point of fixation.

- m. flava a yellowish spot at the anterior extremity of the rima glottidis where the two vocal folds join.

- m. gonorrhoica a spot of red brighter than the surrounding membrane, at the congested orifice of the duct of Bartholin gland, sometimes seen in gonorrhea.

- honeycomb m. edema of the macular region of the retina.

- m. lactea SYN: m. albida.

- m. lutea [TA] SYN: m. of retina.

- m. pellucida SYN: follicular stigma.

- m. of retina [TA] an oval area of the sensory retina, 3 by 5 mm, temporal to the optic disk corresponding to the posterior pole of the eye; at its center is the central fovea, which contains only retinal cones. SYN: m. lutea [TA], area centralis, m. retinae, macular area, punctum luteum, Soemmerring spot, yellow spot.

- m. retinae SYN: m. of retina.

- m. of saccule [TA] the oval neuroepithelial sensory receptor in the anterior wall of the saccule; hair cells of the neuroepithelium support the statoconial membrane and have terminal arborizations of vestibular nerve fibers around their bodies. SYN: m. sacculi [TA], saccular spot.

- m. sacculi [TA] SYN: m. of saccule.

- m. tendinea SYN: m. albida.

- m. of utricle [TA] the neuroepithelial sensory receptor in the inferolateral wall of the utricle; hair cells of the neuroepithelium support the statoconial membrane and have terminal arborizations of vestibular nerve fibers around their bodies; sensitive to linear acceleration in the longitudinal axis of the body and to gravitational influences. SYN: m. utriculi [TA], utricular spot.

- m. utriculi [TA] SYN: m. of utricle.

- maculae utriculosaccularis [TA] SYN: m. (3).

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mac·u·la 'mak-yə-lə n, pl -lae -.lē, -.lī also -las

1) any spot or blotch esp MACULE (2)

2) an anatomical structure having the form of a spot differentiated from surrounding tissues: as

a) MACULA ACUSTICA

b) MACULA LUTEA

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n. (pl. maculae)

a small anatomical area that is distinguishable from the surrounding tissue. The macula lutea is the yellow spot on the retina at the back of the eye, which surrounds the greatest concentration of cones (see fovea). Maculae occur in the saccule and utricle of the inner ear. Tilting of the head causes the otoliths to bend the hair cells, which send impulses to the brain via the vestibular nerve. See also labyrinth.

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mac·u·la (makґu-lə) gen. and pl. maґculae [L.] 1. in anatomy, a stain, spot, or thickening; an area distinguishable from its surroundings by color or other characteristic. 2. m. lutea. 3. macule. 4. a moderately dense scar of the cornea that can be seen without special optical aids, appreciated as a gray spot intermediate between a nebula and a leukoma.