| lens placodes | Paired ectodermal placode's that become invaginated to form the embryonic lens vesicles. Synonym: optic placodes. (05 Mar 2000) |
|---|---|
| lens, simple | <microscopy> A glass disk ground and polished with a spherical figure on one side and a plano, concave, or convex configuration on the other side. (05 Aug 1998) |
| lens stars | Congenital cataracts with opacities along the suture lines of the lens; may be anterior or posterior or both. (05 Mar 2000) |
| lens subluxation | Incomplete rupture of the zonule with the displaced lens remaining behind the pupil. In dislocation, or complete rupture, the lens is displaced forward into the anterior chamber or backward into the vitreous body. When congenital, this condition is known as ectopia lentis. (12 Dec 1998) |
| lens sutures | 9 to 12 faint lines on the anterior and posterior surfaces of the lens that radiate from the poles toward the equator; they mark the lines along which the ends of lens fibres abut. Synonym: lens stars, lens sutures. (05 Mar 2000) |
| lens vesicle | In the embryo, the ectodermal invagination that forms opposite the optic cup; it is the primordium of the lens of the eye. Synonym: lenticular vesicle. (05 Mar 2000) |
| lighthouse lens | <physics> A lens built up, progressively, in zones or steps, each zone with its own individual radius. Considerable spherical correction is attained, and the weight of the lens is greatly reduced. Fresnel lenses were originally designed for lighthouses but they are now attainable for small spotlights, automobile headlights, and similar uses. (05 Aug 1998) |
| alar lamina of neural tube | The dorsal division of the lateral walls of the neural tube in the embryo; it gives rise to neurons relaying afferent impulses to higher centres; in the adult such neurons compose the sensory nuclei of the spinal cord and brainstem. Synonym: lamina alaris, alar plate of neural tube, dorsolateral plate of neural tube, lamina dorsalis, wing plate. (05 Mar 2000) |
| basal lamina | <cell biology> Extracellular matrix characteristically found under epithelial cells. There are two distinct layers: the basal lamina, immediately adjacent to the cells, is a product of the epithelial cells themselves and contains collagen type IV and the reticular lamina is produced by fibroblasts of the underlying connective tissue and contains fibrillar collagen. (15 Nov 1997) |
| basal lamina 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 lamina 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) |
| basal lamina of cochlear | A thin layer of tissue covered with mesothelial cells that separates the cochlea from the scala tympani in the ear. (18 Nov 1997) |
| basal lamina of neural tube | The ventral division of the lateral walls of the neural tube in the embryo; it contains neuroblasts giving rise to somatic and visceral motor neurons. Synonym: lamina basalis, basal plate of neural tube, lamina ventralis, ventral plate of neural tube. (05 Mar 2000) |
| basal lamina of saemicircular duct | The basal membrane underlying the epithelium of the saemicircular duct. Synonym: membrana basalis ductus saemicircularis, basal lamina of saemicircular duct. (05 Mar 2000) |
| basement lamina | <cell biology> Extracellular matrix characteristically found under epithelial cells. There are two distinct layers: the basal lamina, immediately adjacent to the cells, is a product of the epithelial cells themselves and contains collagen type IV and the reticular lamina is produced by fibroblasts of the underlying connective tissue and contains fibrillar collagen. (15 Nov 1997) |