<prompt> Pupil fails to dilate by giving cocaine in :Central sympathetic paralysisCentral parasympathetic paralysisPeripheral parasympathetic paralysisPeripheral sympathetic paralysis.  <response>: Ans. is d peripheral sympathetic paralysis In periphery cocaine blocks the uptake of Adrenaline and Noradrenaline in Adrenergic Nerve ending resulting in higher concentration of sympathetic neurotransmitters Sympathomimetic effect:The peripheral sympathomimetic action of cocaine produces following effect:1. Mydriasis2. Rise in B.P.3. Local vasoconstriction4. TachycardiaTherefore if the peripheral sympathetic system is paralysed it will lead to reverse of the above mentioned actions. 