question_answer 7)

Answer briefly (a) How do you perceive the colour of an object? (b) Which part of our body helps us in maintaining the body balance? (c) How does the eye regulate the amount of light that falls on the retina?  

Answer:

(a) The daylight (photopic) vision and colour vision are functions of cones. In the human eye, there are three types of cones which possess their own characteristic photopigments that respond to red, green and blue lights. The sensations of different colours are produced by various combinations of these cones and their photopigments. When these cones are stimulated equally, a sensation of white light is produced. (b) The crista and macula are the specific receptors of the vestibular apparatus of inner ear which are responsible for the maintenance of balance of the body and posture. (C) The diameter of the pupil is regulated by the muscle fibre of iris. Photoreceptors, rods and cones regulate the amount of light that falls on the retina.