| lower motor neuron | Clinical term used to indicate the final motor neuron's that innervate the skeletal muscles; distinguished from upper motor neuron's of the motor cortex that contribute to the pyramidal or corticospinal tract. See: motor neuron. (05 Mar 2000) |
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| lower motor neuron dysarthria | Dysarthria caused by dysfunction of the motor nuclei and the lower pons or medulla, or other neural connections, central and peripheral to the muscles of articulation. (05 Mar 2000) |
| lower motor neuron lesion | Injury to motor cells in the brainstem or spinal cord, or of the axons derived from them. (05 Mar 2000) |
| vein of olfactory gyrus | A tributary of the basal vein which drains the medial olfactory stria. Synonym: vein of olfactory gyrus. (05 Mar 2000) |
| region of olfactory mucosa | The specialised olfactory receptive area that includes the upper one-third of the nasal septum and the lateral wall above the superior concha; it is lined with olfactory mucosa. Synonym: regio olfactoria tunicae mucosae nasi, olfactory region of tunica mucosa of nose, Schultze's membrane. (05 Mar 2000) |
| glomerular layer of olfactory bulb | A layer composed of spherical bodies, called glomeruli, formed by the synapses of mitral cells with the olfactory nerve fibres derived from the cells of the olfactory epithelium. (05 Mar 2000) |
| roots of olfactory tract | Lateral and medial, the two fibre bands that form the caudal continuation of the olfactory tract which, upon diverging, enclose the olfactory tubercle. (05 Mar 2000) |
| molecular layers of olfactory bulb | The layer's, composed mainly of nerve fibres, on the outer and inner sides of the layer of mitral cells of the bulb. (05 Mar 2000) |
| olfactory | <physiology> Of, pertaining to, or connected with, the sense of smell; as, the olfactory nerves; the olfactory cells. <anatomy> Olfactory organ, an organ for smelling. In vertebrates the olfactory organs are more or less complicated sacs, situated in the front part of the head and lined with epithelium innervated by the olfactory (or first cranial) nerves, and sensitive to odouriferous particles conveyed to it in the air or in water. Origin: L. Olfactus, p.p. Of olfacere to smell; olere to have a smell + facere = to make. See Odour, and Fact. Source: Websters Dictionary (01 Mar 1998) |
| olfactory angle | The angle formed by the plane of the lamina cribrosa and the basicranial axis. (05 Mar 2000) |
| olfactory area | A region at the base of the brain through which numerous small branches of the anterior and middle cerebral arteries (lenticulostriate arteries) enter the depth of the cerebral hemisphere; it is bordered medially by the optic chasm and anterior half of the optic tract, rostrally and laterally by the lateral olfactory stria; its anteromedial part corresponds to the olfactory tubercle. Synonym: substantia perforata anterior, locus perforatus anticus, olfactory area. (05 Mar 2000) |
| olfactory bulb | Ovoid body resting on the cribriform plate of the ethmoid bone where the olfactory nerve terminates. The olfactory bulb contains several types of nerve cells including the mitral cells, on whose dendrites the olfactory nerve synapses, forming the olfactory glomeruli. The accessory olfactory bulb, which receives the projection from the vomeronasal organ via the vomeronasal nerve, is also included here. (12 Dec 1998) |
| olfactory bundle | A fibre system, described by E. Zuckerkandl as "Reichbundel," descending from the transparent septum in front of the anterior commissure toward the base of the forebrain; it contains precommissural fibres of the fornix, fibres from the septum to the hypothalamus and innominate substance, as well as fibres ascending to the septum and hippocampus from the hypothalamus and midbrain; it bears no special relation to the sense of smell. (05 Mar 2000) |
| olfactory cells | Very slender nerve cell's, with large nuclei and surmounted by six to eight long, sensitive cilia in the olfactory epithelium at the roof of the nose; they are the receptors for smell. Synonym: olfactory cells, Schultze's cells. (05 Mar 2000) |
| olfactory cortex | The olfactory cortex, corresponding to the rostral half of the uncus; receiving its major afferents from the olfactory bulb, it is classified as allocortex. See: cerebral cortex. Synonym: olfactory cortex, piriform area. (05 Mar 2000) |