Text B. Muscular tissue

Muscle is the most abundant tissue in the body. It accounts for some two fifth of the body weight. The specialized component is the muscle fiber, a long slender cell or agglomeration of cells which becomes shorter and thicker in response to a stimulus. These fibers are supported and bound together by ordinary connective tissue and supplied with blood vessels and nerves. Three types of muscular tissue can be distinguished on the basis of fine structure and physiological characteristics: smooth, striated and cardiac.

Striated is the largest category of muscle tissue in the body. Striated muscle consists of muscle cells which may be 10-100 mm thick and up to 15 cm long. The nuclei lie immediately beneath the surface of the cells in the directions of the long axis of muscular fibers.

Smooth muscle consists of spindle-shaped cells 40-200 mm long and 4-20 mm thick with a central nucleus. Its fibers, each a single cell, are much shorter than striated fibers.

Cardiac muscle differs from any other muscle. Its fibers are short and thick and form a dense mesh. In cardiac muscle tissue the nuclei lie centrally. In addition, cardiac muscle tissue contains highly refractile, transverse intercalated discs.

Tissues were first described by M.Bichat in 1800. The study of tissues is histology. In a fact, histology is anatomy with a microscope. Histology has greatly enhanced our understanding of anatomy and physiology, and became the principal source of information about the underlying processes of disease. In clinical medicine it is the most valuable method of diagnosis.

X. Say everything you know about 1. muscles in general

2. smooth muscles

3. striated muscles

4. cardiac muscles

XI. Read the text and retell it giving only the general information: