SM Physiology Abbreviation

Smooth Muscle

Smooth muscle is an involuntary non-striated muscle. It is divided into two subgroups; the single-unit (unitary) and multi-unit smooth muscle. Within single-unit cells, the whole bundle or sheet contracts as a syncytium (that is a multinucleate mass of cytoplasm that is not separated into cells). Multi-unit smooth muscle tissues innervate individual cells; as such, they allow for fine control and gradual responses, much like motor unit recruitment in skeletal muscle.