Questions based on Vision.ppt
Revised 6 October 2013
Which structures of the eye are responsible for refraction of light? Which of these
structures can vary the degree of refraction?
What structure produces aqueous humor?
What is glaucoma and how can it lead to blindness?
Name the intrinsic muscles of the eye and describe their functions.
How is the autonomic nervous system involved in regulating the diameter of the pupil?
Explain how a muscarinic acetylcholine receptor antagonist such as atropine can result in
the dilation of the pupil.
Explain how a dilated pupil can be indicative of strong activation of the sympathetic
division of the ANS.
Explain how focusing on a near object for a long time can lead to eye strain. Which
muscle is involved?
Describe the changes in the various structures which participate in accommodating on an
object at a great distance.
Which sets of intrinsic and extrinsic muscles participate in near point accommodation?
Define presbyopia and describe the underlying cause. What is the treatment for
presbyopia?
What abnormalities of the eye contribute to myopia? To hyperopia?
What causes part of the image to be out of focus in a person with astigmatism?
What is a cataract? Why must a person wear glasses after surgery for cataracts?
Which cranial nerves provide efferent innervation of the extraocular muscles?
What is strabismus and which structures can be responsible?
Which areas of the brain receive synapses from axons of retinal ganglion cells?
What is the function of each of the following structures: LGN, suprachiasmatic nucleus,
pretectum and superior colliculus. What sorts of deficits would be expected if each of
these structures was damaged?
What are the synonyms for the striate cortex?
What are saccades and how do they reduce the likelihood of photobleaching? (This
should become apparent after the second lecture/demo on the visual system.)
Describe the visual deficits in each eye that would result from a) severance of the left
optic nerve b) severance of the optic chiasm, and c) severance of the left optic tract.
Axons of retinal ganglion cells of the left nasal retina form synapses in which structures
on which side of the brain?
What advantage is conferred to animals with binocular vision?
What is meant by the term “retinotopy?”
Questions for Vision Part 2
Which types of membrane potentials are produced by each of the cell types in the retina?
Can retinal ganglion cells and amacrine cells produce graded potentials?
How is the fine visual acuity of the fovea related to convergence?
Anatomically, what is the difference between rods and cones?
Functionally, what are the differences between rods and cones?
Of rods and cones, which require brighter light to be activated? How does this relate to
nocturnal vision? Would you expect nocturnal animals to have more rods or more cones?
In terms of rods and cones, why is it possible to see a dim star only if one doesn’t look
directly at it?
What is the anatomical explanation for the “blind spot” in each eye?
What is the only difference in the three types of cones that accounts for their different
spectral sensitivities?
What is meant by the “trichromatic theory of color vision?”
What is the role of retinal and opsin in photoreception? How does each respond to the
absorption of a photon?
How is the cycling of photopigments similar to the cycling of voltage-gated sodium
channels?
Explain how it is that rods and cones are depolarized in the dark? What is the role of
cyclic GMP?
List the events that lead to the closure of Na+ channels in rods and cones beginning with
the absorption of a photon. Be sure to describe the functions of transducin and
phosphodiesterease.
What properties did Hubel and Wiesel discover concerning retinal ganglion cells?
What is meant by “center-surround” receptive field properties?
In what part of the brain are Hubel and Wiesel’s simple, complex, and hypercomplex
cells found? What types of visual stimuli are necessary to activate each of the cell types?
What is meant by the term “parallel processing?” How is this related to the analysis of
motion and color and size and shape of a viewed object?
Of all the sensory systems, why have we devoted so much time to the visual system?