GENERAL HISTOLOGY

Detailed explanation-1: -Smooth muscle, found in the walls of the hollow internal organs such as blood vessels, the gastrointestinal tract, bladder, and uterus, is under control of the autonomic nervous system. Smooth muscle cannot be controlled consciously and thus acts involuntarily.

Detailed explanation-2: -Blood vessels contain only smooth muscle cells. These muscle cells reside within the tunica media along with elastic fibers and connective tissue.

Detailed explanation-3: -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. Skeletal muscle fibers occur in muscles which are attached to the skeleton.

Detailed explanation-4: -Vascular smooth muscle is found in arteries, arterioles, veins, and lymphatic vessels. The contractile state of VSMC establishes the diameter of these vessels and thus resistance to flow.