CO Anatomy & Physiology of the Visual System 3

Question 1

The Edinger-Westphal nucleus provides parasympathetic innervation to which intraocular structures?

Accepted Answer

Sphincter pupillae and ciliary muscle

Answer

The Edinger-Westphal nucleus provides parasympathetic innervation via CN III to both the sphincter pupillae (pupil constriction) and the ciliary muscle (accommodation).

Question 2

Which of the following correctly describes the action of the inferior oblique muscle in primary position?

Accepted Answer

Extorsion, elevation, and abduction

Answer

In primary position, the inferior oblique produces extorsion as its primary action, with secondary actions of elevation and abduction.

Question 3

Panum's fusional area refers to which concept in binocular vision?

Accepted Answer

The region around the horopter within which objects are seen in single binocular vision

Answer

Panum's fusional area is the region around the horopter where objects with slight retinal image disparity are still fused into a single percept, forming the basis of stereopsis.

Question 4

The optic nerve exits the eye through which structure and is surrounded by an extension of the meninges?

Accepted Answer

The lamina cribrosa of the sclera

Answer

The optic nerve exits through the lamina cribrosa, a sieve-like region of the sclera, and is surrounded by extensions of the dura, arachnoid, and pia mater.

Question 5

Accommodation is primarily achieved by which change in the crystalline lens?

Accepted Answer

The lens becomes more convex due to ciliary muscle contraction and zonule relaxation

Answer

During accommodation, ciliary muscle contraction causes the zonular fibers to relax, allowing the inherently elastic lens to become more convex (increased curvature) and thus more powerful.

(CO) Certified Orthoptist Practice Test

(CO) Certified Orthoptist Practice Test

CO Anatomy & Physiology of the Visual System 3