| glaucomatous nerve-fibre bundle scotoma | See: caecocentral scotoma. (05 Mar 2000) |
|---|---|
| Reissner's fibre | A rodlike, highly refractive fibre running caudally from the subcommissural organ throughout the length of the central canal of the brainstem and spinal cord. (05 Mar 2000) |
| medullary cone | The tapering lower extremity of the spinal cord. Synonym: conus medullaris. (05 Mar 2000) |
| medullated nerve fibre | An axon enveloped by a myelin sheath formed by oligodendroglia cells (in brain and spinal cord) or Schwann cells (in peripheral nerves). Synonym: medullated nerve fibre. (05 Mar 2000) |
| reticular fibre | <cell biology> A fine fibre of reticulin found in the extracellular matrix. They are fibres of type III collagen which form the distinctive loose connective tissue stroma of embryonic tissues, mesenchyme, red pulp of the spleen, cortex and medulla of lymph nodes, and the haematopoietic compartments of bone marrow and comprise a substantial portion of the collagen fibres of the skin, blood vessels, synovial membrane, uterine tissue, and granulation tissue. They are characterised by their organization as a reticular meshwork of fine filaments and an affinity for silver and for periodic acid-Schiff stains. (17 Jul 2002) |
| retinal cone | <ophthalmology, physiology> One of the two photoreceptor cell types in the vertebrate retina. In cones the photopigment is in invaginations of the cell membrane of the outer segment. Cones are less sensitive to light than rods, and are differentially sensitive to particular wavelengths of light and therefore important for colour vision. They provide vision with higher spatial and temporal acuity, and it is the combination of signals from cones with different pigments that facilitates colour vision. There are three types of cones, each type sensitive to red, green or blue. Present in large numbers in the fovea. (03 Jul 1999) |
| retraction fibre | Thin projections from crawling cells associated with areas where the cell body is becoming detached from the substratum, but focal adhesions persist. Usually contain a bundle of microfilaments that are under tension. (18 Nov 1997) |
| growth cone | <cell biology> A specialised region at the tip of a growing neurite that is responsible for sensing the local environment and moving toward the neuron's target cell. Growth cones are hand shaped, with several long filopodia that differentially adhere to surfaces in the embryo. Growth cones can be sensitive to several guidance cues, for example: surface adhesiveness, growth factors, neurotransmitters and electric fields (galvanotropism). (18 Nov 1997) |
| growth cone collapse | <cell biology> Loss of motile activity and cessation of advance by growth cones. There are now thought to be specific molecules that inhibit the motility of particular growth cones and are important in establishing correct pathways in developing nervous systems. See: axon pathfinding. (18 Nov 1997) |
| rod fibre | A part of the rod cell of the retina that extends to either side of the cell body; the inner rod fibre terminates in the spherule, a synaptic ending located in the outer plexiform layer. (05 Mar 2000) |
| gutta-percha cone | <dentistry> A cone-shaped, semi rigid root canal filling material composed of gutta-percha and zinc oxide. (05 Mar 2000) |
| chromatic fibre | The coiled filament in which the genes are located, which extends the entire length of a chromosome and exhibits an intensely positive Feulgen test for DNA. Synonym: chromatic fibre. Origin: chromo-+ G. Nema, thread (05 Mar 2000) |
| Rosenthal fibre | An oval or elongated eosinophilic mass believed to represent a modified process of an astrocyte; seen in large numbers in certain slowly growing astrocytomas and areas of chronic reactive gliosis. (05 Mar 2000) |
| pi cone monochromatism | Impaired, but not absent, colour vision with less severely reduced visual acuity than in complete achromatopsia; inherited as an autosomal recessive or as an X-linked disorder (blue cone monochromism; pi cone monochromatism ). (05 Mar 2000) |
| cold cone biopsy | <gynaecology, procedure> A procedure which excises a cone of tissue (mucous membrane) off the cervix for purpose of diagnostics and therapeutics (removes precancerous cells). See: cervical dysplasia. (27 Sep 1997) |