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a) Describe the process of accommodation in the human eye. b) Describe the mechanism of regulation of the amount of light entering the eye.

      

a) Describe the process of accommodation in the human eye.
b) Describe the mechanism of regulation of the amount of light entering the eye.

  

Answers


gregory
a) Accommodation of distant object (far vision)
The ciliary muscles relax; the suspensory ligaments contract and pulled tight ;the lens then becomes (thinner); light from
distant object is less refracted the focused on the fovea; and then interpreted in the brain;
Accommodation of a close object (near vision)
The ciliary muscle contract; the suspensory ligaments relax; the lens then become thicker (more spherical); light from
close object is greatly refracted and focused on the fovea; and then interpreted in the brain;
b) Light enters the eye through the pupil; the radial and circular muscles in the iris control the size of the pupil,
depending upon light intensity ;the muscles work antagonistically.
In bright light (high light intensity) ;the amount of light entering the eye should be low; hence the pupil should be
narrow; radial muscles of the iris relax; the circular muscles contract ; the pupils becomes smaller; while the iris enlarges
thus less light enters the eye;
In dim light/ low light intensity; radial muscles in the iris contract; the inner circular muscles relax; the iris becomes
smaller while pupil enlarges more light enters to the eye;
gregorymasila answered the question on February 23, 2018 at 12:01


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