| motor neuron disease | <disease> Degenerative disease of unknown cause that affects predominantly motor neurons of spinal cord, cranial nerve nuclei and motor cortex. There is speculation that deficiency in ciliary neurotrophic factor may be involved. (18 Nov 1997) |
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| motor neurons | Neurons which activate muscle cells. (12 Dec 1998) |
| motor neurons, gamma | Motor neurons which activate the contractile regions of intrafusal muscle fibres, thus adjusting the sensitivity of the muscle spindles to stretch. Gamma motor neurons may be "static" or "dynamic" according to which aspect of responsiveness (or which fibre types) they regulate. The alpha and gamma motor neurons are often activated together (alpha gamma coactivation) which allows the spindles to contribute to the control of movement trajectories despite changes in muscle length. (12 Dec 1998) |
| motor nuclei | Collections of motor neurons (forming a continuous column in the spinal cord, discontinuous in the medulla and pons) giving origin to the spinal and cranial motor nerves. Synonym: nuclei originis, motor nuclei. (05 Mar 2000) |
| motor nucleus of facial nerve | A group of motor neurons located in the ventrolateral region of the lower pontine tegmentum and innervating the facial muscles, the stapedius muscle in the middle ear, the posterior limb of the musculus digastricus, and the stylohyoid muscle. Synonym: nucleus nervi facialis, facial motor nucleus, motor nucleus of facial nerve, nucleus facialis. (05 Mar 2000) |
| motor nucleus of trigeminal nerve | <anatomy, nerve> A group of motor neurons innervating the muscles of mastication (masseter, temporalis, internal and external pterygoid muscles) and the musculi tensor tympani and tensor veli palatini. The nucleus lies in the upper pontine tegmentum medial to the main sensory nucleus of the trigeminus. Synonym: nucleus motorius nervi trigemini, masticatory nucleus, motor nucleus of trigeminus, nucleus masticatorius. (05 Mar 2000) |
| motor nucleus of trigeminus | <anatomy, nerve> A group of motor neurons innervating the muscles of mastication (masseter, temporalis, internal and external pterygoid muscles) and the musculi tensor tympani and tensor veli palatini. The nucleus lies in the upper pontine tegmentum medial to the main sensory nucleus of the trigeminus. Synonym: nucleus motorius nervi trigemini, masticatory nucleus, motor nucleus of trigeminus, nucleus masticatorius. (05 Mar 2000) |
| motor oculi | <anatomy, nerve> Responsible for motor enervation of upper eyelid muscle, extraocular muscle and pupillary muscle. Lesions of the oculomotor nerve results in ptosis (dropping eyelid), deviation of the eyeball outward, double vision and a dilated pupil. (27 Sep 1997) |
| motor paralysis | Loss of the power of muscular contraction. (05 Mar 2000) |
| motor plate | A motor endplate. (05 Mar 2000) |
| motor point | A point on the skin where the application of an electrical stimulus, via an electrode, will cause the contraction of an underlying muscle. (05 Mar 2000) |
| motor protein | <protein> Proteins that bind ATP and are able to move on a suitable substrate with concomitant ATP hydrolysis. most eukaryotic motor proteins move by binding to a specific site on either actin filaments (myosin) or on microtubules (dynein, kinesin). They are normally elongated molecules with two active binding sites although some kinesin analogues have a single site. The distal end of the molecule normally binds adaptor proteins that enable them to make stable interactions with membranous vesicles or with filamentous structures, which then constitute the cargo to be moved along the substrate filament. (18 Nov 1997) |
| motor root | The motor root of a spinal nerve. Synonym: radix anterior, radix motoria, anterior root, motor root, radix ventralis. (05 Mar 2000) |
| motor root of ciliary ganglion | A branch of the oculomotor nerve supplying parasympathetic preganglionic nerve fibres to the ciliary ganglion. Synonym: radix parasympathica ganglii ciliaris, radix oculomotoria ganglii ciliaris, motor root of ciliary ganglion, oculomotor root of ciliary ganglion, radix brevis ganglii ciliaris, short root of ciliary ganglion. (05 Mar 2000) |
| motor root of trigeminal nerve | <anatomy, nerve> The smaller root of the trigeminal nerve, composed of fibres originating from the trigeminal motor nucleus and emerging from the pons medial to the much larger sensory root, to join the mandibular nerve; it carries motor and proprioceptive fibres to the muscles derived from the first bronchial (mandibular) arch, including the four muscles of mastication, plus the mylohyoid, anterior belly of the digastric, and the tensores tympani and veli palati. Synonym: radix motoria nervi trigemini, masticator nerve, portio minor nervi trigemini. (05 Mar 2000) |