Final answer:
Smooth muscle cells have one centrally located nucleus, are spindle-shaped, and control the movement of internal organs involuntarily.
Step-by-step explanation:
Smooth muscle cells contain a single, centrally located nucleus. These cells are characteristic for being spindle-shaped and for having the ability to move internal organs under involuntary control. Unlike skeletal and cardiac muscle, smooth muscle does not appear striated because it lacks the banded appearance that is found in the other two muscle types.