CO Anatomy & Physiology of the Visual System 1

Question 1

Which extraocular muscle is responsible for primary abduction of the eye?

Accepted Answer

Lateral rectus

Answer

The lateral rectus, innervated by cranial nerve VI (abducens), is the primary abductor of the eye.

Question 2

The visual pathway travels from the retina to the primary visual cortex located in which brain lobe?

Accepted Answer

Occipital lobe

Answer

The primary visual cortex (V1/striate cortex) is located in the occipital lobe, specifically in the calcarine fissure.

Question 3

Which cranial nerve innervates the superior oblique muscle?

Accepted Answer

CN IV (Trochlear)

Answer

The trochlear nerve (CN IV) exclusively innervates the superior oblique muscle, making it the only cranial nerve to exit from the dorsal brainstem.

Question 4

At the optic chiasm, which fibers decussate (cross) to the opposite side?

Accepted Answer

Nasal retinal fibers

Answer

Nasal retinal fibers, which carry temporal visual field information, cross at the optic chiasm, while temporal retinal fibers remain ipsilateral.

Question 5

The fovea centralis contains predominantly which type of photoreceptors?

Accepted Answer

Cones only

Answer

The fovea centralis is packed exclusively with cone photoreceptors, providing maximum visual acuity and color discrimination in bright light.

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