| 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) |
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| onion bulb neuropathy | Designation for any of several demyelinating polyneuropathies in which the nerves are enlarged, due to onion bulb formation-whorls of overlapping Schwann cell processes encircling bare medullated axons, e.g., progressive hypertrophic polyneuropathy. See: hypertrophic interstitial neuropathy. (05 Mar 2000) |
| taste bulb | One of a number of flask-shaped cell nests located in the epithelium of vallate, fungiform, and foliate papillae of the tongue and also in the soft palate, epiglottis, and posterior wall of the pharynx; it consists of sustentacular, gustatory, and basal cells between which the intragemmal sensory nerve fibres terminate. Synonym: caliculus gustatorius, gustatory bud, Schwalbe's corpuscle, taste bulb, taste corpuscle. (05 Mar 2000) |
| end bulb | One of the oval or rounded bodies in which the sensory nerve fibres terminate in mucous membrane. (05 Mar 2000) |
| jugular bulb | <anatomy, vein> One of two dilated parts of the internal jugular vein: the superior bulb (Heister's diverticulum) is a dilation at the beginning of the internal jugular vein in the jugular fossa of the temporal bone; the inferior bulb is a dilat ed portion of the vein just before it reaches the brachiocephalic vein. Synonym: jugular bulb, bulbus venae jugularis. (05 Mar 2000) |
| A layer | <molecular biology> Right handed double helical DNA with approximately 11 residues per turn. Planes of base pairs in the helix are tilted 20 deg away from perpendicular to the axis of the helix. Formed from B DNA by dehydration. (18 Nov 1997) |
| ameloblastic layer | The internal layer of the enamel organ. Synonym: enamel layer. (05 Mar 2000) |
| anterior elastic layer | A transparent homogeneous acellular layer, 6 to 9 um thick, lying between the basal lamina of the outer layer of stratified epithelium and the substantia propria of the cornea; considered to be a basement membrane. Synonym: lamina limitans anterior corneae, anterior elastic layer, Bowman's membrane, lamina elastica anterior, limiting layers of cornea. (05 Mar 2000) |
| anterior layer of rectus abdominis sheath | The portion of the rectus sheath that lies anterior to the muscle, consisting in its upper two-thirds of contributions from the aponeuroses of the external and internal oblique muscles, and in its lower third (below the arcuralt line) of contributions from the aponeuroses of all three muscles of the anterolateral abdominal wall. Synonym: lamina anterior vaginae musculi recti abdominis. (05 Mar 2000) |
| anterior limiting layer of cornea | A transparent homogeneous acellular layer, 6 to 9 um thick, lying between the basal lamina of the outer layer of stratified epithelium and the substantia propria of the cornea; considered to be a basement membrane. Synonym: lamina limitans anterior corneae, anterior elastic layer, Bowman's membrane, lamina elastica anterior, limiting layers of cornea. (05 Mar 2000) |
| bacillary layer | The layer of the retina next to the pigment layer and containing the visual receptors. See: retina, granular layers of retina, neuroepithelial layer of retina. Synonym: bacillary layer. (05 Mar 2000) |
| basal cell layer | The deepest layer of the epidermis, composed of dividing stem cells and anchoring cells. Synonym: basal cell layer, columnar layer, germinative layer, palisade layer, stratum basale, stratum cylindricum, stratum germinativum. (05 Mar 2000) |
| basal layer | The outermost layer of the endometrium which undergoes only minimal changes during the menstrual cycle. Synonym: basal layer. Synonym: stratum basale epidermidis. (05 Mar 2000) |
| basal layer of choroid | The transparent, nearly structureless inner layer of the choroid in contact with the pigmented layer of the retina. Synonym: basal lamina of choroid, basal layer of choroid, Bruch's membrane, Henle's membrane, lamina vitrea, vitreous lamella, vitreous membrane. (05 Mar 2000) |
| basal layer of ciliary body | The inner layer of the ciliary body, continuous with the basal layer of the choroid and supporting the pigment epithelium of the ciliary retina. Synonym: lamina basalis corporis ciliaris, basal layer of ciliary body. (05 Mar 2000) |