CO Anatomy & Physiology of the Visual System 2 — Questions and Answers
Question 1: Which structure in the visual pathway serves as the primary relay station between the retina and the visual cortex?
- Superior colliculus
- Pretectal nucleus
- Lateral geniculate nucleus (LGN) (Correct answer)
- Pulvinar nucleus
Correct answer: Lateral geniculate nucleus (LGN)
The lateral geniculate nucleus (LGN) of the thalamus is the main relay station for visual information traveling from the retina to the primary visual cortex.
Question 2: The pupillary light reflex afferent pathway travels via which structure before reaching the pretectal nucleus?
- Lateral geniculate nucleus
- Superior colliculus
- Optic nerve and optic tract (Correct answer)
- Optic radiations
Correct answer: Optic nerve and optic tract
The afferent limb of the pupillary light reflex travels along the optic nerve and optic tract to the pretectal nucleus in the midbrain, bypassing the LGN.
Question 3: The superior oblique muscle intorts and depresses the eye in which position of gaze?
- Primary position
- Abduction
- Adduction (Correct answer)
- Elevation
Correct answer: Adduction
The superior oblique is the primary depressor and intorter when the eye is in adduction, which is why CN IV palsy causes vertical diplopia worse in adduction.
Question 4: The vestibulo-ocular reflex (VOR) functions primarily to maintain what?
- Binocular fusion during near work
- Stable retinal images during head movement (Correct answer)
- Accurate smooth pursuit eye movements
- Correct vergence alignment
Correct answer: Stable retinal images during head movement
The vestibulo-ocular reflex stabilizes retinal images during head movement by generating compensatory eye movements equal and opposite to head rotation.
Question 5: Optic radiations carrying superior visual field information travel through which anatomical region?
- Meyer's loop in the temporal lobe (Correct answer)
- Parietal white matter
- Internal capsule posterior limb only
- Corpus callosum
Correct answer: Meyer's loop in the temporal lobe
Superior visual field fibers travel through Meyer's loop, an anterior loop of the optic radiation in the temporal lobe, explaining why temporal lobe lesions cause superior quadrantanopia.
Question 6: Which of the following best describes the function of the superior cervical ganglion in ocular physiology?
- Parasympathetic innervation to the ciliary muscle
- Sympathetic innervation to the dilator pupillae and Müller's muscle (Correct answer)
- Motor innervation to the orbicularis oculi
- Sensory innervation to the cornea
Correct answer: Sympathetic innervation to the dilator pupillae and Müller's muscle
The superior cervical ganglion provides sympathetic postganglionic fibers that innervate the dilator pupillae (pupil dilation) and Müller's muscle (upper lid elevation).
Question 7: In the context of retinal correspondence, what is the horopter?
- The angle between the two visual axes
- The locus of points in space that stimulate corresponding retinal points (Correct answer)
- The region of binocular single vision around the fixation point
- The area of the retina with maximum cone density
Correct answer: The locus of points in space that stimulate corresponding retinal points
The horopter is the theoretical locus of all points in space whose images fall on corresponding retinal points, resulting in single binocular vision.
CO Anatomy & Physiology of the Visual System 2
Which structure in the visual pathway serves as the primary relay station between the retina and the visual cortex?