| 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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| 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) |
| perivascular | Situated around a vessel. (18 Nov 1997) |
| perivascular cuffs | See: cuffing. Rotator cuff of shoulder, the upper half of the capsule of the shoulder joint reinforced by the tendons of insertion of the supraspinatus, infraspinatus, teres minor, and subscapularis muscles. Synonym: musculotendinous cuff. (05 Mar 2000) |
| perivascular fibrous capsule | A layer of connective tissue ensheathing the hepatic artery, portal vein, and bile ducts as these ramify within the liver. Synonym: capsula fibrosa perivascularis, perivascular fibrous capsule. Connective tissue capsule surrounding the outer surface of the liver, but continuous with septae of some animals which divide parenchyme into lobule, and with the perivascular fibrous capsule at the porta hepatis. Synonym: tunica fibrosa hepatis, Glisson's capsule. (05 Mar 2000) |
| His' perivascular space | A tunnel-like extension of the subarachnoid space surrounding blood vessels that pass into the brain or spinal cord from the subarachnoid space; the lining of the channel is composed of pia and glial feet of astrocytes; a continuation of the space around capillaries and nerve cells probably does not occur. Synonym: His' perivascular space. (05 Mar 2000) |
| 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) |
| posterior limiting layer of cornea | A transparent homogeneous acellular layer between the substantia propria and the endothelial layer of the cornea; considered to be a highly developed basement membrane. Synonym: lamina limitans posterior corneae, membrana vitrea, Descemet's membrane, Duddell's membrane, entocornea, hyaloid membrane, lamina elastica posterior, limiting layers of cornea, membrana hyaloidea, posterior elastic layer, tunica vitrea, vitreous membrane. (05 Mar 2000) |
| limiting angle | The angle of incidence at which a ray of light, in passing between two media, changes from refraction to total reflection. Synonym: limiting angle. (05 Mar 2000) |
| limiting factor | Environmental factor that limits the growth or activities of an organism or that restricts the size of a population or its geographical range. (09 Oct 1997) |
| limiting layers of cornea | anterior limiting layer of cornea, posterior limiting layer of cornea |