Explanation:
Muscle fibers can be categorized into 3 types:
Cardiac muscle cells: Cardiac muscle cells or cardiomyocytes are the muscle cells (myocytes) that make up the cardiac muscle (heart muscle).
Skeletal muscle cells: An individual skeletal muscle may be made up of hundreds, or even thousands, of muscle fibers bundled together and wrapped in a connective tissue covering. Many muscles are named by the action the muscle performs. These include:
The flexor and extensor; abductor and adductor; levator and depressor; supinator and pronator; sphincter, tensor, and rotator muscles.[6]A flexor muscle decreases the anterior angle at a joint; an extensor increases the anterior angle at a joint.An abductor moves a bone away from the midline; an adductor moves a bone closer to the midline.A levator raises a structure; a depressor moves a structure down.A supinator turns the palm of the hand up; a pronator turns the palm down.A sphincter decreases the size of an opening; a tensor tenses a body part; a rotator turns a bone around its axis.
Smooth muscle cells: Also called involuntary muscle and non-striated muscle, it shows no cross stripes under microscopic magnification. It consists of narrow spindle-shaped cells with a single, centrally located nucleus. Smooth muscle tissue, unlike striated muscle, contracts slowly and automatically. It constitutes much of the musculature of internal organs and the digestive system.