Compare the following :
a) Central neural system (CNS) and peripheral neu-ral system (PNS)
b) Resting potential and action potenial
c) Choroid and retina

Given below are the stages in the generation of optic nerve impulse or action potential on the retina and the role of opsin and retinal in the mechanism of vision. Arrange them in a sequential order. a) Action potential (impulses) are transmitted by the optic nerves to the visual cortex area of the brain. b) Light induces dissociation of retinal from opsin. c) Generates action potential in the ganglion cells through bipolar cells. d) Structural changes in the opsin which induce membrane permeability changes. e) Potential differences are generated in the photoreceptor cells. f) Neural impulses are analyzed by visual cortex area of the brain.

Write the type of system in each of the following: a) Hot water taken in an open vessel b) Hot water taken in a closed metallic vessel c) Hot water taken in a thermos flask