ANATOMY

Detailed explanation-1: -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-2: -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-3: -Phasic or tonic. Smooth muscle may contract phasically with rapid contraction and relaxation, or tonically with slow and sustained contraction. The reproductive, digestive, respiratory, and urinary tracts, skin, eye, and vasculature all contain this tonic muscle type.

Detailed explanation-4: -The smooth muscle is found in the walls of many hollow organs such as stomach, intestines, urinary bladder, and in the walls of passageways, like the veins and arteries of the circulatory system, and the tracts of the urinary, respiratory and reproductive system. It is an involuntary non-striated muscle.

Detailed explanation-5: -Smooth muscle consists of two types single-unit and multi-unit. Single-unit smooth muscle consists of multiple cells connected through connexins that can be stimulated in a synchronous pattern from only one synaptic input. Connexins allow for cell-to-cell communication between groups of single-unit smooth muscle cells.