MUSCLE PHYSIOLOGY

Detailed explanation-1: -Smooth muscle is an involuntary non-striated muscle, so-called because it has no sarcomeres and therefore no striations (bands or stripes). It is divided into two subgroups, single-unit and multiunit smooth muscle.

Detailed explanation-2: -Non-striated muscles are smooth and devoid of striations. Found in the hollows of internal organs such as the stomach, intestines, and urine bladder, among other places. They are also known as involuntary muscles because their activation is not under the control of the human.

Detailed explanation-3: -Cardiac muscle cells are located in the walls of the heart, appear striped (striated), and are under involuntary control. Smooth muscle fibers are located in walls of hollow visceral organs (such as the liver, pancreas, and intestines), except the heart, appear spindle-shaped, and are also under involuntary control.

Detailed explanation-4: -Ultrastructure. Under light microscopy, striated muscles have highly ordered ultrastructure consisting of sarcomeres, which are basic contractile units containing a central myosin-rich dark anisotropic (A) band and two actin-dominated light isotropic (I) bands [12, 13].