| 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) |
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| 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) |
| rod vision | Vision when the eye is dark-adapted. See: dark adaptation, dark-adapted eye. Synonym: night vision, rod vision, scotopia, twilight vision. (05 Mar 2000) |
| 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) |
| anterior basal branch | Anterior basal branch of basal parts of the inferior lobar branches of the right and left pulmonary arteries, and superior basal branches of the right and left inferior pulmonary veins. Synonym: ramus basalis anterior. (05 Mar 2000) |
| anterior basal segment | Anterior basal segment of inferior lobe of right and left lung; lies between middle lobe and diaphragm. Synonym: segmentum basale anterius. (05 Mar 2000) |
| basal | Pertaining to or situated near a base. (18 Nov 1997) |
| basal age | The highest mental age level of the Stanford-Binet intelligence scale at which all items are passed. (05 Mar 2000) |
| basal anaesthesia | Parenteral administration of one or more sedatives to produce a state of depressed consciousness short of a general anaesthesia. (05 Mar 2000) |
| basal area | <botany> The cross-sectional area of a tree trunk measured in square inches, square centimetres, etc., basal area is normally measured at 4.5 feet above ground level and is used as a measure of dominance, the most commonly used tool for measuring basal area is a diameter tape or a D-tape (then convert to basal area). (09 Oct 1997) |
| basal body | <cell biology> Structure found at the base of eukaryotic cilia and flagella consisting of a continuation of the nine outer sets of axonemal microtubules but with the addition of a C tubule to form a triplet (like the centriole). May be self replicating and serves as a nucleating centre for axonemal assembly. Anchored in the cytoplasm by rootlets. Synonymous with kinetosome. (18 Nov 1997) |
| basal body temperature | <biology> The temperature taken at its lowest point in the day, usually in the morning before getting out of bed. (09 Oct 1997) |