lamina densa

lamina /lam·i·na/ (lam´ĭ-nah) pl. la´minae   [L.]

1. layer; a thin, flat plate of a larger composite structure.

2. l. of vertebra.

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basal lamina 

1. the layer of the basement membrane lying next to the basal surface of the adjoining cell layer, comprising two layers, the electron-lucent lamina lucida and the electron-dense lamina densa.

2. sometimes, the entire basement membrane.

3. l. basalis.

lamina basa´lis 

1. one of the pair of longitudinal zones of the embryonic neural tube, from which develop the ventral gray columns of the spinal cord and the motor centers of the brain.

2. basal l. (1).

lamina basila´ris  the posterior wall of the cochlear duct, separating it from the scala tympani.

Bowman's lamina  see under membrane.

lamina choroidocapilla´ris  the inner layer of the choroid, composed of a single-layered network of small capillaries.

lamina cribro´sa 

1. fascia cribrosa.

2. (of ethmoid bone) the horizontal plate of ethmoid bone forming the roof of the nasal cavity, and perforated by many foramina for passage of olfactory nerves.

3. (of sclera) the perforated part of the sclera through which pass the axons of the retinal ganglion cells.

lamina den´sa  see basal l. (1).

elastic lamina 

1. Bowman's membrane.

2. Descemet's membrane.

epithelial lamina  the layer of ependymal cells covering the choroid plexus.

lamina lu´cida  see basal l. (1).

nuclear lamina  a tightly woven meshwork that lines the nuclear side of the inner nuclear membrane; it is believed to control the shape of the nucleus.

lamina pro´pria 

1. the connective tissue layer of mucous membrane.

2. the middle fibrous layer of the tympanic membrane.

lamina ra´ra  lamina lucida; see basal l. (1). In the lung alveoli and renal glomeruli, one may occur on each side of the lamina densa.

reticular lamina 

1. a layer of the basement membrane, adjacent to the connective tissue, seen in some epithelia.

2. l. reticularis.

lamina reticula´ris  the perforated hyaline membrane covering the organ of Corti.

Rexed's laminae , spinal laminae an architectural scheme used to classify the structure of the spinal cord, based on the cytological features of the neurons in different regions of the gray substance.

Rexed's laminae in a cross section of the spinal cord at approximately the level of the seventh cervical vertebra (C7).

lamina spira´lis 

1. a double plate of bone winding spirally around the modiolus, dividing the spiral canal of the cochlea into the scala tympani and scala vestibuli.

2. a bony projection on the outer wall of the cochlea in the lower part of the first turn.

terminal lamina of hypothalamus  the thin plate derived from the telencephalon, forming the anterior wall of the third ventricle of the cerebrum.

lamina of vertebra , lamina of vertebral arch either of the pair of broad plates of bone flaring out from the pedicles of the vertebral arches and fusing together at the midline to complete the posterior part of the arch and provide a base for the spinous process.

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lamina densa,

a layer of epithelial basal lamina that appears dark in electron micrographs.

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lamina [lam´ĭ-nah] (L.)

1. a thin, flat plate or stratum of a composite structure; called also layer.

2. vertebral lamina.

basal lamina (lamina basa´lis) the layer of the basement membrane lying next to the basal surface of the adjoining cell layer composed of an electron-dense lamina densa and an electron-lucent lamina lucida.

lamina basila´ris the posterior wall of the cochlear duct, separating it from the scala tympani.

lamina choroidocapilla´ris the inner layer of the choroid, composed of a single-layered network of small capillaries.

lamina cribro´sa

1. fascia cribrosa.

2. (of ethmoid bone) the horizontal plate of ethmoid bone forming the roof of the nasal cavity, and perforated by many foramina for passage of olfactory nerves.

3. (of sclera) the perforated part of the sclera through which pass the axons of the retinal ganglion cells.

lamina den´sa an electron-dense layer of the basal lamina, consisting mainly of collagen fibrils and proteoglycans; it closely follows the plasma membrane of the basal aspect of the adjacent cell layer, from which it is separated by the lamina lucida (or the lamina rara in the renal glomerulus and pulmonary alveolus).

lamina du´ra a layer of the alveolar bone that is thin and particularly compact and appears as a line on dental x-rays. Called also bundle bone.

epithelial lamina the layer of ependymal cells covering the choroid plexus.

lamina fus´ca the pigmentary layer of the sclera.

lamina lu´cida an electron-dense layer of the basal lamina lying between the lamina densa and the adjoining cell layer; in the pulmonary alveolus and renal glomerulus it is divided into the internal and external laminae rarae.

lamina pro´pria

1. the connective tissue layer of mucous membrane.

2. the middle fibrous layer of the tympanic membrane.

lamina ra´ra

1. in the renal glomerulus and pulmonary alveolus, one of the layers of lamina lucida surrounding the lamina densa; the lamina rara externa is on the epithelial side and the lamina rara interna is on the endothelial side.

2. a term sometimes used as a synonym for lamina lucida.

reticular lamina a layer of the basement membrane, adjacent to the connective tissue, seen in some epithelia; it is of variable thickness and is composed of condensed connective tissue with a reticulum of collagen fibers.

Rexed's laminae an architectural scheme used to classify the structure of the spinal cord, based on the cytological features of the neurons in different regions of the gray substance. It consists of nine laminae (I–IX) that extend throughout the cord, roughly paralleling the dorsal and ventral columns of the gray substance, and a tenth region (lamina X) that surrounds the central canal and consists of the dorsal and ventral commissures and the central gelatinous substance.

spiral lamina (lamina spira´lis)

1. a double plate of bone winding spirally around the modiolus, dividing the spiral canal of the cochlea into the scala tympani and scala vestibuli.

2. a bony projection on the outer wall of the cochlea in the lower part of the first turn.

terminal lamina of hypothalamus the thin plate derived from the telencephalon, forming the anterior wall of the third ventricle of the cerebrum.

vertebral lamina (lamina of vertebral arch) either of the pair of broad plates of bone flaring out from the pedicles of the vertebral arches and fusing together at the midline to complete the dorsal part of the arch and provide a base for the spinous process of the vertebra.