The intestines, airways, blood vessels and stomach are lined with smooth muscle tissue. Smooth muscle tissue contraction is responsible for involuntary movements in the internal organs. This muscle tissue is also found around the urinary tract and in genitals.

The intestines carry chyme, whereas blood vessels carry blood. The stomach moves the chime onwards. There is no rush to do this, so smooth muscle cells work slowly.

Smooth muscle cells work involuntarily. The function of muscle cells is controlled by the autonomic nervous system. The smooth muscle cells are oval and overlap with each other. There is only one nucleus in the cells.