| ARN | acute renal necrosis; acute retinal necrosis; arcuate nucleus; Association of Rehabilitation Nurses |
|---|---|
| BARN | bilateral acute retinal necrosis |
| BRAO | branch retinal artery occlusion |
| BRVO | branch retinal vein occlusion |
| CHRPE | congenital hypertrophy of the retinal pigment epithelium |
| ocular cone | The cone of light in the interior of the eyeball with the base formed by the rays entering through the pupil and the apex focused on the retina. (05 Mar 2000) |
|---|---|
| outer cone fibre | Located between the inner segment and the cell body. (05 Mar 2000) |
| theca interna cone | The conical thickening of thecal cells of an ovarian follicle with its apex pointed toward the surface. (05 Mar 2000) |
| elastic cone | Thicker lower portion of the elastic membrane of the larynx, extending between the cricoid cartilage and the vocal ligaments, the latter actually being a thickening of the free, superior margin of the conus elasticus. Synonym: cricovocal membrane, elastic cone. Synonym: cricothyroid ligament. (05 Mar 2000) |
| twin cone | Two retinal cone's fused together. (05 Mar 2000) |
| l-cone | Long wavelength sensitive cone (red cone). (05 Mar 2000) |
| long cone technique | The use of a cone distance of 14 inches or more in making oral roentgenographs. (05 Mar 2000) |
| loss cone | In a magnetic mirror machine, particles with a large velocity parallel to the magneitc field and a small velocity perpendicular to the field will be able to escape past the magnetic mirror (see magnetic mirror). In that case the velocity distribution function (see distribution function) will be almost zero in the region of velocity space that allows particles to escape. The shape of that region (in a velocity space diagram with parallel velocity and perpendicular velocity as the axes) is a cone. When a particle undergoes a collision, its velocity gets somewhat randomised. Particles that are scattered into that cone are lost very quickly (in one mirror bounce time). Thus it is called a loss cone. Because of the loss cone, the theoretical maximum particle confinement time of a magnetic mirror machine can be only a few times the particle collision time, this is generally seen as a showstopper for mirror-based fusion research. (09 Oct 1997) |
| all-trans-retinal | The orange retinaldehyde resulting from the action of light on the rhodopsin of the retina, which converts the 11-cis-retinal component of the rhodopsin to all-trans-retinal plus opsin. Synonym: trans-retinal, visual yellow. (05 Mar 2000) |
| blood-retinal barrier | Specialised nonfenestrated tightly-joined endothelial cells that form a transport barrier for certain substances between the retinal capillaries and the retinal tissue. (12 Dec 1998) |
| central retinal artery occlusion | <ophthalmology> The sudden blockage of the retinal artery with a blood clot that commonly leads to a painless but irreversible blindness in that eye. (12 Jan 1998) |
| central retinal fovea | A depression in the centre of the macula retinae containing only cones and lacking blood vessels. Synonym: fovea centralis retinae, central pit. (05 Mar 2000) |
| central retinal vein occlusion | <ophthalmology> The sudden blockage of the retinal vein with blood clot that commonly leads to a painless irreversible blindness in that eye. (12 Jan 1998) |
| retinal | 1. <anatomy> Pertaining to the retina. 2. <biochemistry> The aldehyde of retinol, derived by the oxidative enzymatic splitting of absorbed dietary carotene and having vitamin A activity. In the retina, retinal combines with opsins to form visual pigments. One isomer, 11 cis retinal combines with opsin in the rods (scotopsin) to form rhodopsin or visual purple. Another, all trans retinal (trans r.), visual yellow, xanthopsin) results from the bleaching of rhodopsin by light, in which the 11 cis form is converted to the all trans form. Retinal also combines with opsins in the cones (photopsins) to form the three pigments responsible for colour vision. (18 Nov 1997) |
| retinal adaptation | Adjustment to degree of illumination. (05 Mar 2000) |