| thalamic nuclei | Several groups of nuclei in the thalamus that serve as the major relay centres for sensory impulses in the brain. (12 Dec 1998) |
|---|---|
| thalamic syndrome | <syndrome> A syndrome produced by infarction of the postero-inferior thalamus causing transient hemiparesis, severe loss of superficial and deep sensation with preservation of crude pain in the hypalgic limbs which frequently have vasomotor or trophic disturbances. Synonym: Dejerine-Roussy syndrome. (05 Mar 2000) |
| thalamic tenia | The sharp edge or angle between the superior and medial surface of the thalamus on either side; to it is attached the epithelial lamina forming the roof of the third ventricle. Synonym: tenia ventriculi tertii, thalamic tenia. (05 Mar 2000) |
| lateral thalamic peduncle | The massive group of fibres that emerges from the laterodorsal side of the thalamus to join the corona radiata; it reciprocally connects the lateral nucleus and the geniculate bodies of the thalamus with the corresponding regions of the cerebral cortex. Synonym: pedunculus thalami lateralis. (05 Mar 2000) |
| reticular | <anatomy> Pertaining to or resembling a net. (16 Dec 1997) |
| reticular activating system | <physiology> A physiological term denoting that part of the brainstem reticular formation that plays a central role in the organism's bodily and behavorial alertness. It extends as a diffusely organised neural apparatus through the central region of the brainstem into the subthalamus and the intralaminar nuclei of the thalamus; by its ascending connections it affects the function of the cerebral cortex in the sense of behavioural responsiveness; its descending (reticulospinal) connections transmit its activating influence upon bodily posture and reflex mechanisms (e.g., muscle tonus), in part by way of the gamma motor neurons. See: reticular formation. Synonym: non-specific system. (05 Mar 2000) |
| reticular cartilage | <anatomy> Rarely used terms for fibrocartilage. (05 Mar 2000) |
| reticular cell | A cell with processes making contact with those of other similar cell's to form a cellular network; along with the network of reticular fibres, the reticular cell's form the stroma of bone marrow and lymphatic tissues. (05 Mar 2000) |
| reticular degeneration | <ophthalmology> Severe epidermal oedema resulting in multilocular bullae. (05 Mar 2000) |
| reticular dystrophy of cornea | <ophthalmology> Bilateral, progressive, superficial degeneration of the corneal epithelium and adjacent Bowman's membrane. (05 Mar 2000) |
| reticular erythematous mucinosis | <syndrome> A reticular erythematous dermatitis of the upper trunk, more common in women, in which there is perivascular infiltrate of lymphocytes, few plasma cells, and upper dermal deposits of mucin; worsens on exposure to ultraviolet light. Synonym: reticular erythematous mucinosis. (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) |
| reticular formation | <anatomy, neurology> A region extending from the pons & medulla oblongata through the mesencephalon, characterised by a diversity of neurons of various sizes and shapes, arranged in different aggregations and enmeshed in a complicated fibre network. (12 Dec 1998) |
| reticular lamina | A major component of the basement membrane, as seen by light microscopy; it consists largely of reticular fibres and ground substances. (05 Mar 2000) |
| reticular layer of corium | The thicker deep layer of the corium consisting of dense irregularly arranged connective tissue. Synonym: reticular layer of corium, stratum reticulare cutis, tunica propria corii. (05 Mar 2000) |