What is the main difference between muscle cells and nerve cells?

Muscle cells (myocytes) contract to produce movement while nerve cells send messages from receptor cells to either glandular cells or muscle cells relaying messages throughout the body.
While nerve cells are involved in the transmission of neural synapses (hence the name), myocytes contract to move the skeletal bones and move the body. Muscle cells can be smooth (visceral), cardiac, or skeletal. Smooth muscle cells make up the internal structure of organs, skeletal muscle cells attach to bones to provide movement, and cardiac muscles provide the involuntary "pumps" necessary to circulate blood through the body. Shown below are smooth muscles (B.), cardiac muscles (C.), and skeletal (A.).