| 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) |
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| pial-glial membrane | The dual outer lining of the brain and spinal cord, composed of the glial limiting membrane and the pia mater. (05 Mar 2000) |
| internal limiting membrane | Formed by the expanded inner ends of Muller's fibres, outer limiting membrane, not a membrane but a row of junctional complexes. Synonym: membrana limitans. (05 Mar 2000) |
| limiting membrane of retina | One of two layers of the retina: (05 Mar 2000) |
| periventricular fibres | A heterogeneous system of thin nerve fibres in the periventricular gray matter of the hypothalamus; the dorsal longitudinal fasciculus is a caudal continuation of the system. Synonym: fibrae periventriculares. (05 Mar 2000) |
| posterior periventricular nucleus | A nucleus located in the middle hypothalamus in the most ventral part of the third ventricle near the entrance of the infundibular recess. Its small cells are in close contact with the ependyma. (12 Dec 1998) |
| leukomalacia, periventricular | A disease of premature or newborn infants hypoxic and ischemic in nature and leading to infarction of brain white matter and cerebral ventricle enlargement. (12 Dec 1998) |
| glial | Pertaining to glia or neuroglia. (05 Mar 2000) |
| glial cell | <pathology> Specialised cells that surround neurons, providing mechanical and physical support and electrical insulation between neurons. (17 Dec 1997) |
| glial fibrillary acidic protein | <protein> This protein, found in microfilaments of glial cells, helps distinguish glial from nonglial tumours. A laboratory stain is used to test for its presence. (16 Dec 1997) |
| glial filament | <cell biology> Intermediate filaments of glial cells, made of glial fibrillary acidic protein. (17 Dec 1997) |
| Abbe's law of limiting resolution | <physics> For a periodic structure of units separated by distance d and obliquely illuminated by the unrefracted ray and one of the two diffracted rays (extremely oblique illumination). Abbe applied the law of diffraction: d = 0.5 lambda /NA, where: lambda = wavelength of the monochromic light or shortest of mixed wavelengths NA = the limiting numerical aperture (NA) of objective or condenser. (05 Aug 1998) |
| 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) |
| anterior limiting ring | The periphery of the cornea marking the termination of Descemet's membrane and the anterior border of the trabecular meshwork; an important landmark in gonioscopy. Synonym: Schwalbe's ring. (05 Mar 2000) |
| rate-limiting step | <biochemistry> The slowest step in a metabolic pathway, or the step in an enzymatic reaction that requires the greatest amount of energy to initiate. (17 Dec 1997) |