Muscle Types

Smooth muscle or "involuntary muscle" consists of spindle shaped muscle cells found within the walls of organs and structures such as the esophagus, stomach, intestines, bronchi, uterus, ureters, bladder, and blood vessels.

Smooth muscle cells contain only one nucleus and no striations.

• Cardiac muscle is also an "involuntary muscle" but it is striated in structure and appearance. Like smooth muscle, cardiac muscle cells contain only one nucleus. Cardiac muscle is found only within the heart.

• Skeletal muscle or "voluntary muscle" is anchored by tendons to the bone and is used to effect skeletal movement such as locomotion. Skeletal muscle cells are multinucleated with the nuclei peripherally located.

Skeletal muscle is called 'striated' because of the longitudinally striped appearance under light microscopy.