<prompt> When the sympathetic nervous system is activated:Norepinephrine is released by the vascular smooth muscle cellsAcetylcholine is released onto vascular smooth muscle cellsNorepinephrine is released from axons onto the arteriolar wallThe arterioles constrict because nitric oxide production is suppressed  <response>: Ans. C. Norepinephrine is released from axons onto the arteriolar wallNerve fibers, not vascular smooth muscle, release norepinephrine. The norepinephrine from the sympathetic nerves simply diffuses from the axons and binds to specific receptors on smooth muscle cells. 