basal lamina


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Related to basal lamina: connective tissue, Hemidesmosomes

lamina

 [lam´ĭ-nah] (L.)
1. a thin, flat plate or stratum of a composite structure; called also layer.
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
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.

ba·sal lam·i·na

1. an amorphous extracellular layer applied to the basal surface of epithelium and also investing muscle cells, fat cells, and Schwann cells; thought to be a selective filter and to serve both structural and morphogenetic functions. Its principal component is a layer (consisting mostly of type IV collagen) called the lamina densa, which has a dense appearance under the electron microscope. On either side of the lamina densa are two less dense layers, called the lamina rarae.
See also: basement membrane, lamina densa.
2. Synonym(s): lamina densa

basal lamina

(1) Basement membrane; membrana basalis [NH3]. 
(2) Basement membrane of glomerulus; membrana basalis glomeruli NH3.

basal lamina

see BASEMENT MEMBRANE.

ba·sal lam·i·na

(bāsăl lami-nă)
1. An a-morphous extracellular layer applied to the basal surface of epithelium and also investing muscle cells, fat cells, and Schwann cells. Its principal component is a layer (consisting mostly of type IV collagen) called the lamina densa. On either side of the lamina densa are two less dense layers, called the laminae rarae.
2. Synonym(s): lamina densa.
References in periodicals archive ?
The large nuclei of spermatocytes in the pachytene stage were located in the middle of the seminiferous epithelium, while the nuclei of Sertoli cells, type A spermatogonia, and intermediate spermatogonium were closer to the basal lamina of the seminiferous tubule.
These nests clearly have their origin within the epithelium since they are separated from the underlying connective tissue by a basal lamina. Closer examination of the ultrastructure revealed that apoptosis of the larval epithelium and active cell proliferation of the adult epithelium coincide with a temporary vigorous folding of the basal lamina underlying the epithelia.
It consists of flattened dedifferentiated cells arranged on a well-developed basal lamina and connected to each other by zonulae adhaerentes.
In the quantitative analysis of total number of GC/mm of basal lamina, and relative quantities of AA+, PAS+ and AA/ PAS+ GC populations in the respiratory epithelium of the nasal septum, data collected from the maxilloturbinate and nasopharynx were analyzed using a 3X3 factorial design.
Morphometric estimates of the numeric cell density of OSNs immunohistochemically reactive for OMP (protein indicator of mature OSNs) were determined via light microscopy (790 x final magnification) by counting the number of nuclear profiles of these immunoreactive neuroepithelial cells in the OE lining the medial surface of 2E in T3 (Figure 1) and dividing by the length of the underlying basal lamina. The length of the basal lamina was determined from the contour length of a computerized digital image of the basal lamina using the Scion Image program (Scion Corporation, Frederick, MD).
While studying the basal lamina, BioStratum's collaborating researchers at the Karolinska Institute (Stockholm, Sweden) discovered that laminin-5 is involved in the migration of most epithelial cells as well as epithelial cell derived cancers.
After three to four weeks, a complete basal lamina -- a layer of specially arranged cells -- is formed between the epidermis and dermis.
Hypoxic groups: In the hypoxic group 1 some of the seminiferous tubules showed detachment of the basal lamina. Spaces of different sizes have appeared within the epithelial layer with vacuoles in the centre.
It consists of three components: (a) a single layer of squamous epithelial cells, the endothelium; (b) the basal lamina of the endothelial cells; and (c) the suyenciothclinl layer, consisting of loose connective tissue.
The intratubular compartment is normally surrounded by a lamina propria composed of a double-layered basal lamina and 5-7 external cellular layers [34].
In this period of regeneration, the cells from the basal layer had already initiated the synthesis of the basal lamina located right beneath the new regenerated epithelium (Figures 2 and 3), which had been lost at the time of the fin amputation.