COA Ocular Anatomy and Physiology 2

Question 1

The crystalline lens is held in position by which structure?

Accepted Answer

Zonular fibers (suspensory ligaments)

Answer

Zonular fibers connect the lens equator to the ciliary body, suspending the lens in the optical axis.

Question 2

Accommodation refers to which physiologic process?

Accepted Answer

Changing lens curvature to focus at different distances

Answer

Accommodation changes the curvature of the crystalline lens by ciliary muscle contraction to focus objects at near.

Question 3

The vitreous humor consists primarily of:

Accepted Answer

Water with collagen fibrils and hyaluronic acid

Answer

The vitreous is approximately 99% water supported by a framework of collagen fibrils and hyaluronic acid.

Question 4

Which photoreceptor cells are responsible for night (scotopic) vision?

Accepted Answer

Rods

Answer

Rod photoreceptors are extremely sensitive to light and mediate vision under low-light (scotopic) conditions.

Question 5

Visual information travels from the retina via the optic nerve to which structure first?

Accepted Answer

Lateral geniculate nucleus of the thalamus

Answer

Retinal ganglion cell axons project through the optic nerve to synapse in the lateral geniculate nucleus of the thalamus.

COA - Certified Ophthalmic Assistant Practice Test