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Question
Assertion :Circular smooth muscles of iris contract when bright light falls on the eye. Reason: Pupil gets constricted by the contraction circular smooth muscles of iris.
Assertion :Circular smooth muscles of iris contract when bright light falls on the eye. Reason: Pupil gets constricted by the contraction circular smooth muscles of iris.
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Solution
The correct option is B Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
The wall of each eyeball is made up of three concentric layer-sclerotic, choroid and retina. The choroid is a highly vascular pigmented layer separating the sclerotic from the inner layer of the eyeball. It is connected in front to a thick structure called ciliary body. Iris is a pigmented, muscular, opaque diaphragm which extends from the ciliary body in front of a biconvex transparent lens. Iris has a small central aperture called pupil. Light passing through the cornea enters through the pupil to fall on the lens behind it. The iris has two sets of smooth muscles arranged circularly and radially around the pupil. The pupil gets constricted by the contraction of circular muscles to reduce the amount of light falling on the lens. On the contrary, the pupil gets dilated by the contraction of radial muscles to increase the amount of light falling on the lens.
So, the correct answer is 'Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion'.
The wall of each eyeball is made up of three concentric layer-sclerotic, choroid and retina. The choroid is a highly vascular pigmented layer separating the sclerotic from the inner layer of the eyeball. It is connected in front to a thick structure called ciliary body. Iris is a pigmented, muscular, opaque diaphragm which extends from the ciliary body in front of a biconvex transparent lens. Iris has a small central aperture called pupil. Light passing through the cornea enters through the pupil to fall on the lens behind it. The iris has two sets of smooth muscles arranged circularly and radially around the pupil. The pupil gets constricted by the contraction of circular muscles to reduce the amount of light falling on the lens. On the contrary, the pupil gets dilated by the contraction of radial muscles to increase the amount of light falling on the lens.
So, the correct answer is 'Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion'.
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