| nail plate | 1. <anatomy> The horny scale of plate of epidermis at the end of the fingers and toes of man and many apes. "His nayles like a briddes claws were." (Chaucer) The nails are strictly homologous with hoofs and claws. When compressed, curved, and pointed, they are called talons or claws, and the animal bearing them is said to be unguiculate; when they incase the extremities of the digits they are called hoofs, and the animal is ungulate. 2. <ornithology, zoology> The basal thickened portion of the anterior wings of certain hemiptera. The terminal horny plate on the beak of ducks, and other allied birds. 3. A slender, pointed piece of metal, usually with a head, used for fastening pieces of wood or other material together, by being driven into or through them. The different sorts of nails are named either from the use to which they are applied, from their shape, from their size, or from some other characteristic, as shingle, floor, ship-carpenters', and horseshoe nails, roseheads, diamonds, fourpenny, tenpenny (see Penny), chiselpointed, cut, wrought, or wire nails, etc. 4. A measure of length, being two inches and a quarter, or the sixteenth of a yard. Nail ball, a round projectile with an iron bolt protruding to prevent it from turning in the gun. Nail plate, iron in plates from which cut nails are made. On the nail, in hand; on the spot; immediately; without delay or time of credit; as, to pay money on the nail. "You shall have ten thousand pounds on the nail." . To hit the nail on the head, to hit most effectively; to do or say a thing in the right way. Origin: AS. Naegel, akin to D. Nagel, OS OHG. Nagal, G. Nagel, Icel. Nagl, nail (in sense 1), nagli nail (in sense 3), Sw. Nagel nail (in senses 1 and 3), Dan. Nagle, Goth. Ganagljan to nail, Lith. Nagas nail (in sense 1), Russ. Nogote, L. Unguis, Gr, Skr. Nakha. Source: Websters Dictionary (01 Mar 1998) |
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| neural plate | <embryology> A region of embryonic ectodermal cells, called neuroectoderm, that lie directly above the notochord. During neurulation, they change shape, so as to produce an infolding of the neural plate (the neural fold) that then seals to form the neural tube. (04 Jul 1999) |
| neutralization plate | A metal plate used for the internal fixation of a long bone fracture to neutralise the forces producing displacement. (05 Mar 2000) |
| suction plate | In dentistry, a plate held in place by atmospheric pressure. (05 Mar 2000) |
| notochordal plate | The sheet of notochordal cells that are intercalated in the endodermal roof of the primitive yolk sac. See: head process. (05 Mar 2000) |
| dorsal plate of neural tube | The thin layer of the embryonic neural tube connecting the alar plate's dorsally. Synonym: dorsal plate of neural tube. (05 Mar 2000) |
| dorsolateral plate of neural tube | The dorsal division of the lateral walls of the neural tube in the embryo; it gives rise to neurons relaying afferent impulses to higher centres; in the adult such neurons compose the sensory nuclei of the spinal cord and brainstem. Synonym: lamina alaris, alar plate of neural tube, dorsolateral plate of neural tube, lamina dorsalis, wing plate. (05 Mar 2000) |
| quadrigeminal plate | The roofplate of the mesencephalon formed by the quadrigeminal bodies. Synonym: lamina tecti mesencephali, tectum mesencephali, lamina quadrigemina, quadrigeminal lamina, quadrigeminal plate. (05 Mar 2000) |
| quarter-wave plate | <microscopy> A compensator giving a retardation of about 130 nm, and a phase shift of 1/4 ~, thus constituting a device used with a polarizer and analyser designed to produce circularly polarized light. (05 Aug 1998) |
| oral plate | A circumscribed area of fusion of foregut endoderm and stomodeal ectoderm in the embryo which breaks through early in development to establish the oral opening. See: buccopharyngeal membrane. (05 Mar 2000) |
| orbital plate | A thin plate of ethmoid bone forming part of the medial wall of the orbit and the lateral wall for the ethmoidal labyrinth. Synonym: lamina orbitalis ossis ethmoidalis, lamina papyracea, orbital lamina of ethmoid bone, orbital layer of ethmoid bone, orbital plate, paper plate, papyraceous plate. (05 Mar 2000) |
| orbital plate of ethmoid bone | A thin plate of ethmoid bone forming part of the medial wall of the orbit and the lateral wall for the ethmoidal labyrinth. Synonym: lamina orbitalis ossis ethmoidalis, lamina papyracea, orbital lamina of ethmoid bone, orbital layer of ethmoid bone, orbital plate, paper plate, papyraceous plate. (05 Mar 2000) |
| terminal plate | A thin plate passing upward from the optic chiasm and forming the rostral boundary of the third ventricle; membrane closing the rostral neuropore. Synonym: lamina terminalis cerebri, lamina cinerea, terminal plate, velum terminale. (05 Mar 2000) |
| end plate | <anatomy, physiology> The area of sarcolemma immediately below the synaptic region of the motor neuron in a neuromuscular junction. most often refers to the end of a nerve fibre against a skeletal muscle fibre, to which it transmits nerve signals. (18 Nov 1997) |
| end plate potential | <physiology> Depolarisation of the sarcolemma as a result of acetylcholine release from the motoneuron causing an influx of sodium ions. The endplate potential is the sum of quantal miniature endplate potentials. Development of the end plate potential is blocked by curare. (18 Nov 1997) |