Multiple Choice Questions'Adaptation' of eyes in dark is due to
depletionof vision pigment in rods
depletion of vision pigment in cones
repletion of vision pigment in rods
repletion of vision pigment in cones
C.
repletion of vision pigment in rods
Two types of photoreceptor cells are present in retina, ie, rods and cones.
(i) Rods : These cells are active in dark rhodopsin, a vision pigment is present in rods. In strong light, rhodopsin is bleached due to splitting of its two components, ie, scotopsin and retinal.
(ii) Cones : These cells are active in strong light. Iodopsin a pigment is present in cones. These cells produce hare coloured image in bright light.
Which of the following is important for muscle contraction and nerve impulse transmission?
Ca2+ ions
Ca2+ and Mg2+ ions
Mg2+ ions
Fe2+ ions
In parasympathetic nervous system, which of the following is released?
Epinephrine
Norepinephrine
Serotonin
Acetylcholine
The velocity of conduction of nerve impulse in frog is
300 m/s
same as of electricity
faster than sound
30 m/s
Eustachian canal connects
middle ear with external ear
middle ear with internal ear
external ear with internal ear
pharynx with middle ear
From outer to inside the sequence of three bones present in the middle ear of mammals is
malleus, stapes and incus
stapes, malleus and incus
malleus, incus and stapes
incus, malleus and stapes
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