Question: Indicate which of the following statements about vascular smooth muscle is FALSE: 
 Options:  <1> Its main function is to maintain the tone of the vessels. <2> It is contracted by an increase in the intracellular calcium concentration. <3> Its contraction is controlled by the binding of calcium to troponin. <4> Its tone is controlled by the autonomic nervous system. <5> The endothelium modulates vascular smooth muscle tone.
3