| black membrane | <chemistry> An artificial phospholipid membrane formed by painting a solution of phospholipid in organic solvent over a hole in a hydrophobic support immersed in water. Drainage of the solvent from the film produces diffraction colours until the thickness falls below the wavelength of light it then appears to be black. The structure is an extended bimolecular leaflet. (18 Nov 1997) |
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| Bogros' serous membrane | A membrane of the episcleral space (of Tenon). (05 Mar 2000) |
| Bowman's membrane | 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) |
| bruch membrane | The membrane, also called the lamina basalis choroideae, that acts as a support structure on the inner side of the choroid (the vascular sheet that supplies the retinal pigment epithelium and the outer portion of the sensory retina adjacent to it). It is 7 microns thick and is composed of the basement membranes of the choriocapillaris endothelium and the retinal pigment epithelium. The membrane stops at the optic nerve, as does the retinal pigment epithelium. (12 Dec 1998) |
| Bruch's membrane | 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) |
| Brunn's membrane | The epithelium of the olfactory region of the nose. (05 Mar 2000) |
| bucconasal membrane | A thin, transient epithelial sheet separating the primitive nasal cavity from the stomodeum in the seven-week-old human embryo. Synonym: oronasal membrane. (05 Mar 2000) |
| buccopharyngeal membrane | A bilaminar (ectoderm and endoderm) membrane derived from the prochordal plate; after the embryonic head fold has evolved it lies at the caudal limit of the stomodeum. Synonym: oral membrane, oropharyngeal membrane. (05 Mar 2000) |
| vaginal synovial membrane | A sheath of synovial membrane enveloping certain of the tendons; it contains a small amount of synovial fluid. Synonym: vagina synovialis tendinis, mucous sheath of tendon, theca tendinis, vagina mucosa tendinis, vaginal synovial membrane. (05 Mar 2000) |
| germinal membrane | In many eggs with a large amount of yolk, cell division (cleavage) is restricted to a superficial layer of the fertilized egg (meroblastic cleavage). This layer is termed the blastoderm. In birds it is a flat disc of cells at one pole of the egg and in insects an outer layer of cells surrounding the yolk mass. (18 Nov 1997) |
| paroral membrane | <biology> In ciliates the cilia in the region of the mouth may be fused into a paroral membrane. (18 Nov 1997) |
| vestibular membrane | The membrane separating the cochlear duct from the vestibular canal; it consists of squamous epithelial cells with microvilli toward the ductus, a basement membrane, and a thin layer of connective tissue toward the scala. Synonym: membrana vestibularis, paries vestibularis ductus cochlearis, Reissner's membrane, vestibular wall of cochlear duct. (05 Mar 2000) |
| glassy membrane | The basement membrane present between the stratum granulosum and the theca interna of a vesicular ovarian follicle; it becomes very prominent in large atretic follicles, the basement membrane and associated connective tissue of the hair follicle. Synonym: hyaline membrane. (05 Mar 2000) |
| virginal membrane | An obsolete term for hymen. (05 Mar 2000) |
| glial limiting membrane | A dense, resilient membrane forming the true capsule of the brain and spinal cord, composed of the processes of astrocytes (macroglia cells) and covered throughout by the pia mater, which firmly adheres to it; the two membranes are collectively called the pial-glial membrane. Synonym: membrana limitans gliae. (05 Mar 2000) |