Examples of Muscle Tissue

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Labeled examples of Muscle Tissue at 1000 X. These may help you find material under the microscope.

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Muscle tissues differ in size and internal organization. Striated Muscle or skeletal muscle (sometimes referred to as "voluntary" muscle) has very large cells. These form a cylinder or "fiber" that can be quite long. This elongated cell is actually formed by the fusion of a number of cells in a long row. The original nuclei and their many organelles also remain after fusion. But, there is only one motor end plate that stimulates this megacell or syncytium. So this almost becomes a colony of smaller cells without divisions between them. Smooth muscle, in contrast, has no organized striations caused by the overlap of sarcomere subfibers. The cells are small, tapered, and unremarkable. Cardiac muscle can only be found in the heart. The cells are often "frayed" or "split" on the ends which terminate in clear spaces - the intercalated disks. These disks pass excitation from one cell to the next while the frayed structure passes impulses outward to many other cells or, in one case, the AV junction, converges them on single cells. This can be quite helpful in passing excitation around a healthy heart, but can become problematic if heart damage occurs.