| 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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| Aaron's rod | 1. A rod with one serpent twined around it, thus differing from the caduceus of Mercury, which has two. 2. <botany> A plant with a tall flowering stem; especially. The great mullein, or hag-taper, and the golden-rod. (19 Mar 1998) |
| analyzing rod | A device used with a surveyor to determine the relative positions of parallel surfaces and undercuts when designing removable partial dentures. (05 Mar 2000) |
| basal rod | <microbiology> Rod shaped intracellular organelle lying below the undulating membrane of Trichomonas. Generates active bending associated with local loss of birefringence at the bending zone, probably as a result of conformational change in the longitudinal lamellae. Major protein approximately 90 kD. (10 Nov 1998) |
| Maddox's rod | A glass rod, or a series of parallel glass rod's, that converts the image of a light source into a streak of light perpendicular to the axis of the rod. The position of this streak in relation to the image of the light source seen by the fellow eye indicates the presence and amount of heterophoria. (05 Mar 2000) |
| germinal rod | One of the minute elongated bodies resulting from the repeated division of the oocyst during sporogony. In the case of the malarial parasite, it is the form that is concentrated in the salivary glands and introduced into the blood by the bite of a mosquito; it enters the liver cells (exoerythrocytic cycle), whose progeny, the merozoites, infect the red blood cells to initiate clinical malaria. Synonym: germinal rod, zoite, zygotoblast. Origin: sporo-+ G. Zoon, animal (05 Mar 2000) |
| retinal rod | <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) |
| golden-rod | <botany> A tall herb (Solidago Virga-aurea), bearing yellow flowers in a graceful elongated cluster. The name is common to all the species of the genus Solidago. <botany> Golden-rod tree, a shrub (Bosea Yervamora), a native of the Canary Isles. Source: Websters Dictionary (01 Mar 1998) |
| rod | 1. A straight and slender stick; a wand; hence, any slender bar, as of wood or metal (applied to various purposes). Specifically: An instrument of punishment or correction; figuratively, chastisement. "He that spareth his rod hateth his son." (Prov. Xiii. 24) A kind of sceptor, or badge of office; hence, figuratively, power; authority; tyranny; oppression. "The rod, and bird of peace." . A support for a fishing line; a fish pole. <machinery> A member used in tension, as for sustaining a suspended weight, or in tension and compression, as for transmitting reciprocating motion, etc.; a connecting bar. An instrument for measuring. 2. A measure of length containing sixteen and a half feet; called also perch, and pole. Black rod. <anatomy> Rods and cones, the elongated cells or elements of the sensory layer of the retina, some of which are cylindrical, others somewhat conical. Origin: The same word as rood. See Rood. Source: Websters Dictionary (01 Mar 1998) |
| rod cell | <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 cell of retina | 1. A straight and slender stick; a wand; hence, any slender bar, as of wood or metal (applied to various purposes). Specifically: An instrument of punishment or correction; figuratively, chastisement. "He that spareth his rod hateth his son." (Prov. Xiii. 24) A kind of sceptor, or badge of office; hence, figuratively, power; authority; tyranny; oppression. "The rod, and bird of peace." . A support for a fishing line; a fish pole. <machinery> A member used in tension, as for sustaining a suspended weight, or in tension and compression, as for transmitting reciprocating motion, etc.; a connecting bar. An instrument for measuring. 2. A measure of length containing sixteen and a half feet; called also perch, and pole. Black rod. <anatomy> Rods and cones, the elongated cells or elements of the sensory layer of the retina, some of which are cylindrical, others somewhat conical. Origin: The same word as rood. See Rood. Source: Websters Dictionary (01 Mar 1998) |
| rod disks | Membranous disk's of flattened sacs about 14 nm thick that occur in the outer segment of rods of the retina. (05 Mar 2000) |
| rod fibre | A part of the rod cell of the retina that extends to either side of the cell body; the inner rod fibre terminates in the spherule, a synaptic ending located in the outer plexiform layer. (05 Mar 2000) |
| rod granule | The nucleus of a retinal cell connecting with one of the rods. (05 Mar 2000) |
| rod monochromatism | Achromatopsia with absent colour vision, nystagmus, reduced visual acuity, and light aversion. Synonym: rod monochromatism, typical achromatopsia. (05 Mar 2000) |