Parts of Nervous System. Nervous System: Nervous system is the chief controlling and coordinating system of the body. It controls and regulates all activities of the body, whether voluntary or involuntary, and adjusts the individual (organism) to the given surroundings.
Compared to skeletal muscle, smooth-muscle cells are small. They are spindle-shaped, about 50 to 200 microns long and only 2 to 10 microns in diameter. They have no striations or sarcomeres. Instead, they have bundles of thin and thick filaments (as opposed to well-developed bands) that correspond to myofibrils.
There is one MAJOR difference between smooth muscle and skeletal muscle that we need to consider here: Unlike skeletal muscle, smooth muscle can be made to contract by hormones and paracrine agents. Smooth Muscle Cells can also be activated/inhibited by hormones: Smooth muscle cells are not solely dependent on innervation for their inputs.