| 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) |
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| 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) |
| epiphysial plate | The disc of cartilage between the metaphysis and the epiphysis of an immature long bone permitting growth in length. Synonym: cartilago epiphysialis, epiphysial cartilage. (05 Mar 2000) |
| equatorial plate | <cell biology> Region of the mitotic spindle where chromosomes are aligned at metaphase: as its name suggests, it lies midway between the poles of the spindle. (06 Mar 1998) |
| ethmovomerine plate | The central portion of the ethmoid bone, forming a distinct element at birth. (05 Mar 2000) |
| tympanic plate of temporal bone | The bony plate forming the greater part of the anterior wall of the bony part of the external acoustic meatus and the tympanic cavity and the posterior wall of the mandibular fossa. Synonym: pars tympanica ossis temporalis, tympanic part of temporal bone. (05 Mar 2000) |
| Kuhne's plate | The endplate of a motor nerve fibre in a muscle spindle. (05 Mar 2000) |
| urethral plate | An endodermal plate located ventromedially in the developing genital tubercle of a young embryo; it later opens to form the lining of the penile urethra. (05 Mar 2000) |
| floor plate | Ventral midline thinning of the developing neural tube, a continuity between the basal laminae of either side; opposite of roof plate. Synonym: ventral plate. (05 Mar 2000) |
| lateral plate | A nonsegmented mass of mesoderm on the lateral periphery of the embryonic disk. (05 Mar 2000) |