| motor decussation | The intercrossing of the bundles of the pyramidal tracts at the lower border region of the medulla oblongata. Synonym: decussatio pyramidum, decussatio motoria, motor decussation. (05 Mar 2000) |
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| motor endplate | The specialised postsynaptic region of a muscle cell. The motor endplate is immediately across the synaptic cleft from the presynaptic axon terminal. Among its anatomical specializations are junctional folds which harbor a high density of cholinergic receptors. See: neuromuscular junction (12 Dec 1998) |
| motor fibres | Nerve fibre's that transmit impulses that activate effector cells, e.g., in muscle or gland tissue. (05 Mar 2000) |
| motor-generator | <physics> Device used to store energy by accelerating a rotating flywheel to high speeds, energy may be rapidly discharged and converted to shorter-pulse energy. (Used to power TFTR, the electric utility would be a little unhappy if TFTR were to suddenly draw its 30 MW+ of power at random intervals. (09 Oct 1997) |
| motor image | The image of body movements. (05 Mar 2000) |
| motor nerve | <anatomy, nerve> An efferent nerve conveying an impulse that excites muscular contraction; motor nerves in the autonomic nervous system also elicit secretions from glandular epithelia. (05 Mar 2000) |
| motor nerve of face | <anatomy, nerve> The facial nerve enervates the muscles of the face (facial expression). Lesion of the facial nerve cause a drooping to one side of the face, inability to wrinkle the forehead, inability to whistle, inability to close the eye and deviation of the mouth to the unaffected side. Synonym: cranial nerve VII. (27 Sep 1997) |
| motor neuron | Synonym for motoneuron. (18 Nov 1997) |
| 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) |
| 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) |