This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous System, Subject name: Physiology
Sympathetic system has adrenergic nerve endings at all sites except- 
Select and explain. 
A. Heart, B. Blood vessels in skeletal muscles, C. Eye, D. None
B: Blood vessels in skeletal muscles
Answer: B: Blood vessels in skeletal muscles 
Explanation: 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