This section is from the book "Animal Physiology: The Structure And Functions Of The Human Body", by John Cleland. Also available from Amazon: Animal Physiology, the Structure and Functions of the Human Body.
Unstriped Muscular Tissue is often arranged in bands of indefinite length like the striped fibres; but even when this is the case, it consists of a series of elongated fusiform corpuscles varying usually from 1/600 to 1/300 of an inch in length, and known as fibre-cells, although possessing no proper cell-wall. These fibre-cells are flat, with long tapering extremities, an elliptic or rod-like nucleus in the middle, and at each end of the nucleus usually a few granules. They are of dense consistence, and adhere one to another tenaciously by means of a material acted on by nitric acid.
Fig. 31. Fibre-Cells or Unstriped Fibre.