Our Visual System Has a Remarkable Dynamic Range

question 7

Essay

Our visual system has a remarkable dynamic range. When you go to a matinee movie (during the daytime) and walk out of the theater it is difficult to see. After a few minutes your eyes adapt to the new light levels. Some of the molecular mechanisms of light adaptation are known and most involve changes in Ca²⁺ concentration. (A)


(B)

Figure Q4-13
A. Based on the data from the experiments shown in Figure Q4-13, what is one mechanism of adaptation? Figure Q4-13A shows the dark-adapted response to a flash of light in wild type and GCAP knockout mice. Figure Q4-13B shows the rod response to a flash of light relative to the same flash after dark adaptation.
B. What is the probable molecular mechanism of reduced light adaptation involving GCAP?

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Definitions:

Middle Ear

The part of the ear that contains three small bones (the hammer, anvil, and stirrup) that transmit sound vibrations from the eardrum to the inner ear.

Outer Ear

The outermost part of the ear, consisting of the pinna and the external auditory canal.

Middle Ear

The section of the ear between the eardrum and the oval window that amplifies sound waves through the ossicles to the inner ear.

Amplifies Sound Waves

Increases the magnitude or intensity of sound waves, making them louder or more pronounced.