Test 154  (Ocular physiology)
1. Inhibition of the Edinger-Westphal nucleus:
a. causes relaxation of the iris sphincter

b. causes contraction of the iris dilator

c. occurs in deep sleep

d. occurs with narcotics

e. occurs with increased luminance


2. The following are involved in colour vision:
a. P pathway

b. M pathway

c. area V8 of visual cortex

d. area V3 of visual cortex

e. geniculate layer 3-6

3. The following are true about saccade:
a. it has a higher velocity than pursuit movements

b. the visual acuity is increased during saccades

c. horizontal saccade is controlled by the pons

d. vertical saccade is controlled by the mid-brain

e. burst neurones are important in the generation of 


4. True statements about visual adaptation include:
a. light adaptation takes longer than dark adaptation

b. dark adaptation reaches its maximum in about 20 

c. in dark adapted eye, a higher intensity of light is 
    required to stimulate cones than rods

d. people who wear red goggles in the light adapt 
    quicker in the dark than those who do not wear them

e. the time required for dark adaptation is related to the 
    time needed to build up rhodopsin stores.


5. With regard to light perception:
a. the fovea contains only cones

b. the cones have a lower threshold to light than rods

c. rods respond most to the red-yellow end of light

d. rods respond most to wavelengths of about 500nm

e. all photopigments in the retina contains carotinoid
    derived from diet

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