SENSATION AND PERCEPTION
VISION SENSORY AND PERCEPTUAL PROCESSING
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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constricts.
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dilates.
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remains constant.
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transduces electromagnetic energy into electrochemical energy.
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Detailed explanation-1: -The normal pupil size in adults varies from 2 to 4 mm in diameter in bright light to 4 to 8 mm in the dark. The pupils are generally equal in size. They constrict to direct illumination (direct response) and to illumination of the opposite eye (consensual response). The pupil dilates in the dark.
Detailed explanation-2: -Pupils dilate (get larger) when room light is dimmed. Pupils are round and equal in size, in both bright and dim light. Pupils quickly and symmetrically constrict to a bright light directed into either of the eyes and when the bright light swings between the two eyes.
Detailed explanation-3: -Pupillary reflexes involve the autonomic (Edinger-Westphal) component of the oculomotor nucleus. In the light reflex, the pupils constrict when light is shone on the retina. If one eye only is stimulated, both pupils constrict, the so-called consensual reflex.
Detailed explanation-4: -The iris contains two sets of smooth muscles that control the size of the pupil (Figure 7.2). The sphincter muscle fibers form a ring at the pupil margin so that when the sphincter contracts, it decreases (constricts) pupil size.