These are about 8 nm in diameter and, being the thinnest of the cytoskeletal filaments, are also called microfilaments. (In skeletal muscle fibers they are called thin filaments.) Some functions of actin filaments: 1  form a band just beneath the plasma membrane that.  provides mechanical strength to the cell.
Muscle tissue varies with function and location in the body. In mammals the three types are: skeletal or striated muscle; smooth or non-striated muscle; and cardiac muscle, which is sometimes known as semi-striated.n vertebrates, there is a third muscle tissue recognized: 1  Cardiac muscle (myocardium), found only in the heart, is a striated muscle similar in structure to skeletal muscle but not subject to voluntary control.
A muscle may act ordinarily either under the control of the will or without conscious control. Muscles that can be controlled at will are referred to as voluntary muscles. Those that are not under the control of the will (volition) are called involuntary muscles. Examples of involuntary muscles are the smooth muscles, which are muscles lacking striations when viewed under a microscope. This is why involuntary muscles are sometimes called non-striated or un-striped muscles.