| somatic nerve | <anatomy, nerve> One of the nerve's of parietal sensation or voluntary motion, as distinguished from the visceral sensory, involuntary motor and secretory nerve's. (05 Mar 2000) |
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| somatic nucleus | The larger nucleus (or sometimes nuclei) in ciliate protozoans. Derived from the micronucleus by a process of DNA polytenisation. The DNA in the macronucleus is actively transcribed. The macronucleus degenerates before conjugation. (18 Nov 1997) |
| somatic recombination | One of the mechanisms used to generate diversity in antibody production is to rearrange the DNA in B-cells during their differentiation, a process that involves cutting and splicing the immunoglobulin genes. Somatic recombination via homologous crossing over occurs at a low frequency in Aspergillus, Drosphilia and Saccharomyces and in mammalian cells in culture. It may be detected through the production of homozygous patches or sectors after mitosis of cells heterozygous for suitable marker genes. (18 Nov 1997) |
| somatic reproduction | Asexual reproduction by fission or budding of somatic cells. (05 Mar 2000) |
| somatic sensory cortex | Somatosensory cortex, the region of the cerebral cortex receiving the somatic sensory radiation from the ventrobasal nucleus of the thalamus; it represents the primary cortical processing mechanism for sensory information originating at the body surfaces (touch) and in deeper tissues such as muscle, tendons, and joint capsules (position sense); it corresponds approximately to Brodmann's areas 1, 2, 3 on the postcentral gyrus. Synonym: somesthetic area. (05 Mar 2000) |
| somatic swallow | A swallowing pattern with muscular contractions which appear to be under control of the person at a subconscious level; distinguished from visceral swallow. Visceral swallow, the immature swallowing pattern of an infant or a person with tongue thrust, resembling peristaltic wavelike muscular contractions observed in the gut; adult or mature swallowing is more volitional and therefore somatic. (05 Mar 2000) |
| special somatic afferent column | A column of gray matter in the hindbrain of the embryo, represented in the adult by the nuclei of the auditory and vestibular nerves. (05 Mar 2000) |