Human Anatomy Part 1 - K. A. Dyubenko, A. K. Kolomiytsev, Yu. B. Chaykovsky 2002

General Part
Structure of the Human Body
Tissues - Muscle Tissue - Non-striated Muscle Tissue

Non-Striated Muscle tissue of mesenchymal origin forms the muscular coats of Internal Organs. Smooth myocytes are typically spindle-shaped, ranging from 15 to 500 µm in length and 5 to 8 µm in thickness. The Cell nuclei are elongated lengthwise and may acquire a corkscrew-like appearance upon cell contraction. Organelles in these Cells are poorly developed. As the cytolemma elongates, it forms numerous pinocytotic vesicles that transmit stimuli into the cell interior, which in turn triggers contraction.

The contractile apparatus of non-striated myocytes (myofibrils) consists of thinner myofilaments formed by Actin and thicker ones formed by Myosin. Myocytes are bounded by a basement membrane, as well as Collagen (reticular) and elastic fibers. These Structural components of Cytology/cytology/32.html">Smooth muscle tissue are produced by the smooth myocytes themselves. Efferent (motor) innervation of smooth myocytes is provided by postganglionic fibers of the Autonomic Nervous system. Adjacent myocytes form Gap Junctions (nexuses) with one another through openings in the basement membrane, ensuring functional interaction between the cells.

Non-striated muscle tissue of epidermal origin is formed by myoepithelial cells originating from the cutaneous mesoderm. They have a stellate (branched) shape and are part of the sweat, mammary, and Salivary Glands. Located between the epithelial cells and the basement membrane of the secretory portions of glands and small excretory ducts, they contract to facilitate the expulsion of secretion.

Non-striated muscle tissue of neural origin develops during the embryonic Formation of the Eyeball from the Cells of the optic cup wall. It comprises the Muscles of the iris of the eyeball that dilate or constrict the pupil.



Last update: 08/08/2026

Editorial and Educational Adaptation: This material has been compiled based on the primary/original source text. The project team performed an editorial review, corrected technical inaccuracies, structured sections, and adapted the content for an educational format.

What was processed:

  • elimination of formatting defects (OCR errors, structural breaks, corrupted characters);
  • editorial organization of content;
  • standardization of terminology in accordance with academic sources;
  • verification of factual statements against the original source text.

All mentions of the author, publication year, and origin of the primary text have been preserved in accordance with the source.