Smooth muscle generally occurs as bundles or sheets of elongate fusiform cells with finely tapered ends (Fig. 10.16). The cells, also called fibers, range in length from 20 /xm in the walls of small blood vessels to about 200 fxm in the wall of the intestine; they may be as large as 500 /xm in the wall of the uterus during pregnancy. Smooth muscle cytoplasm stains rather evenly with eosin in routine IT&E preparations because of the concentrations of actin and myosin that these cells contain. The nuclei of smooth muscle cells are located in the center of the cell and often have a corkscrew appearance in longitudinal section. This characteristic is due to contraction of the cell during fixation and is often useful in distinguishing smooth
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