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.
Cardiac muscle is also sometimes considered to be involuntary muscle. However, cardiac muscle shares features of both smooth and skeletal muscle tissue. It is striated like skeletal muscle tissue, but its contractions are involuntary, like those of smooth muscle tissue.Cardiac muscle is unique in that is particularly invulnerable to fatigue.nvoluntary muscles are muscles that are not controllable consciously, and instead contract due to unconscious impulses sent by the autonomic nervous system or certain specialized cells or hormones. Both smooth muscle and cardiac muscle can be classified as involuntary muscles.