<prompt> Sympathetic system has adrenergic nerve endings at all sites except-HeartBlood vessels in skeletal musclesEyeNone  <response>: Ans. is b i.e., Blood vessels in skeletal muscles Sympathetic adrenergic fibers are those which secrete endogenous catecholamines either adrenaline, norepinephrine nor-adrenaline or dopamine Some sympathetic fibers do not secrete catecholamines but secrete acetylcholine -i Sweat glandsii Blood vessels in skeletal muscles Sympathetic fibers Adrenergic Cholinergic Nor-adrenalineDopamineAdrenaline Sweat glands Most postganglionic sympathetic supply Mesentric renal vessels Adrenal medulla Blood vessels in skeletal muscles 