| rod nuclear cell | <pathology> Immature neutrophils released from the bone marrow reserve in response to acute demand. (18 Nov 1997) |
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| rod outer segment | <ophthalmology, physiology> Major photoreceptor cell of vertebrate retina (about 125 million in a human eye). Columnar cells (about 40m long, 1m diameter) having three distinct regions: a region adjacent to and synapsed with, the neural layer of the retina contains the nucleus and other cytoplasmic organelles, below this is the inner segment, rich in mitochondria, that is connected through a thin neck (in which is located a ciliary body) to the outer segment. The outer segment largely consists of a stack of discs membrane infoldings that are incompletely separated in cones) that are continually replenished near the inner segment and that are shed from the distal end and phagocytosed by the pigmented epithelium. The membranes of the discs are rich in rhodopsin, the pigment that absorbs light. (03 Jul 1999) |
| rod outer segments | The portion of the retinal rod cell between the inner segment and the pigment epithelium layer of the retina. (12 Dec 1998) |
| withe-rod | <botany> A North American shrub (Viburnum nudum) whose tough osierlike shoots are sometimes used for binding sheaves. Source: Websters Dictionary (01 Mar 1998) |
| harrington rod insertion | <orthopaedics> A procedure that involves fusing together two or more vertebrae in the spine using either bone grafts or metal rods (Harrington rods). This procedure may be used to correct kyphosis or scoliosis. It is also used in those who require spine stabilisation due to vertebral damage from ruptures discs, fractures, osteomyelitis, osteoarthritis or tumour. (27 Sep 1997) |
| enamel rod inclination | The direction of the enamel rods with reference to the outer surface of the enamel of a tooth. (05 Mar 2000) |
| enamel rod sheath | Organic covering of the individual enamel rod. (05 Mar 2000) |
| achromatic vision | A severe congenital deficiency in colour perception, often associated with nystagmus and reduced visual acuity. Synonym: achromatic vision, monochromasia, monochromasy, monochromatism. Origin: G. A-priv. + chroma, colour, + opsis, vision (05 Mar 2000) |
| binocular vision | Vision with a single image, by both eyes simultaneously. (05 Mar 2000) |
| blue vision | A condition in which all objects appear blue; may temporarily follow cataract extraction. Synonym: blue vision, cyanopia. Origin: cyano-+ G. Opsis, vision (05 Mar 2000) |
| red vision | An abnormality of vision in which all objects appear to be tinged with red. Synonym: red vision. Origin: erythro-+ G. Ops, eye (05 Mar 2000) |
| vision | 1. <ophthalmology> The act or faculty of seeing, sight. 2. <psychiatry> An apparition, a subjective sensation of vision not elicited by actual visual stimuli. 3. Visual acuity, symbol V. Origin: L. Visio (18 Nov 1997) |
| vision, binocular | The blending of separate images seen by each eye into one composite image. (12 Dec 1998) |
| vision disorders | Visual impairment limiting one or more of the basic functions of the eye: visual acuity, dark adaptation, colour vision, or peripheral vision. Visual disability refers to inability of the individual to perform specific visual tasks, such as reading, writing, orientation, or traveling unaided. It is to be differentiated from eye diseases which are restricted to diseases of the eye, the organ and its anatomical parts. (12 Dec 1998) |
| vision disparity | The difference between two images on the retina when looking at a visual stimulus. This occurs since the two retinas do not have the same view of the stimulus because of the location of our eyes. Thus the left eye does not get exactly the same view as the right eye. (12 Dec 1998) |