| SAQ | short arc quadriceps [muscle] |
|---|---|
| SAX-PM | short-axis plane, papillary muscle |
| SC | conditioned stimulus; sacrococcygeal; Sanitary Corps; scalenus [muscle]; scapula; Schwann cell; scia... |
| SM | Master of Science; sadomasochism; self-monitoring; silicon microphysiometer; simple mastectomy; skim... |
| SMA | sequential multiple analysis or analyzer; sequential multichannel autoanalyzer; simultaneous multich... |
| smooth muscle tissue | <anatomy, pathology, physiology> Muscle tissue in vertebrates made up from long tapering cells that may be anything from 20-500m long. Smooth muscle is generally involuntary and differs from striated muscle in the much higher actin/myosin ratio, the absence of conspicuous sarcomeres and the ability to contract to a much smaller fraction of its resting length. Smooth muscle cells are found particularly in blood vessel walls, surrounding the intestine (particularly the gizzard in birds) and in the uterus. The contractile system and its control resemble those of motile tissue cells (e.g. Fibroblasts, leucocytes) and antibodies against smooth muscle myosin will cross react with myosin from tissue cells, whereas antibodies against skeletal muscle myosin will not. See: dense bodies. (18 Nov 1997) |
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| smooth muscle tumour | A tumour composed of smooth muscle tissue, as opposed to leiomyoma, a tumour derived from smooth muscle. (12 Dec 1998) |
| Soemmerring's muscle | A fasciculus occasionally passing from the thyrohyoid muscle to the isthmus of the thyroid gland. Synonym: musculus levator glandulae thyroideae, elevator muscle of thyroid gland, Soemmerring's muscle. (05 Mar 2000) |
| sphincter muscle | <anatomy> A ringlike band of muscle fibres that constricts a passage or closes a natural orifice, also called musculus sphincter. Origin: L., Gr. Sphinkter = that which binds tight (18 Nov 1997) |
| sphincter muscle of common bile duct | Smooth muscle sphincter of the common bile duct immediately proximal to the hepatopancreatic ampulla; it is this sphincter that controls the flow of bile in the duodenum. Synonym: musculus sphincter ductus choledochi, Boyden's sphincter, choledochal sphincter, sphincter muscle of common bile duct. (05 Mar 2000) |
| sphincter muscle of pancreatic duct | Smooth muscle sphincter of the main pancreatic duct immediately proximal to the hepatoduodenal, ampulla. Synonym: musculus sphincter ductus pancreatici, pancreatic sphincter, sphincter muscle of pancreatic duct. (05 Mar 2000) |
| sphincter muscle of pupil | A ring of smooth muscle fibres surrounding the pupillary border of the iris. Synonym: musculus sphincter pupillae, sphincter muscle of pupil. (05 Mar 2000) |
| sphincter muscle of pylorus | A thickening of the circular layer of the gastric musculature encircling the gastroduodenal junction. Synonym: musculus sphincter pylori, sphincter muscle of pylorus. (05 Mar 2000) |
| sphincter muscle of urethra | Origin, ramus of pubis; insertion, with fellow in median raphe behind and in front of urethra; action, constricts membranous urethra; nerve supply, pudendal. Synonym: musculus sphincter urethrae, external urethral sphincter, Guthrie's muscle, musculus compressor urethrae, musculus constrictor urethrae, musculus sphincter urethrae membranaceae, sphincter muscle of urethra, Wilson's muscle. (05 Mar 2000) |
| sphincter muscle of urinary bladder | The complete collar of smooth muscle cells of the neck of the urinary bladder which extend distally to surround the preprostatic sportion of the male urethra. There is not a comparable structure in the neck of the femoral bladder; the internal urethral sphincter may exist to prevent reflux of semen into bladder. Synonym: annulus urethralis, internal urethral sphincter, musculus sphincter vesicae, preprostate urethral sphincter, proximal urethral sphincter, sphincter muscle of urinary bladder. (05 Mar 2000) |
| spinalis capitis muscle | <anatomy> An inconstant extension of spinalis cervicis to the occipital bone, sometimes fusing with semispinalis capitis. Synonym: musculus spinalis capitis, biventer cervicis, spinal muscle of head. (05 Mar 2000) |
| spinalis cervicis muscle | <anatomy> An inconstant or rudimentary muscle; origin, spinous processes of sixth and seventh cervical vertebrae; insertion, spinous processes of axis and third cervical vertebra; action, extends cervical spine; nerve supply, dorsal primary rami of cervical. Synonym: musculus spinalis cervicis, musculus spinalis colli, spinal muscle of neck. (05 Mar 2000) |
| spinalis muscle | <anatomy> The medial component of the erector spinae muscle; it is comprised of the spinalis capitis, spinalis cervicis, and spinalis thoracis muscles. Synonym: musculus spinalis, spinal muscle. (05 Mar 2000) |
| spinal muscle | <anatomy> The medial component of the erector spinae muscle; it is comprised of the spinalis capitis, spinalis cervicis, and spinalis thoracis muscles. Synonym: musculus spinalis, spinal muscle. (05 Mar 2000) |
| spinal muscle of head | <anatomy> An inconstant extension of spinalis cervicis to the occipital bone, sometimes fusing with semispinalis capitis. Synonym: musculus spinalis capitis, biventer cervicis, spinal muscle of head. (05 Mar 2000) |