CPOA Ocular Anatomy 2 — Questions and Answers
Question 1: Which layer of the cornea is responsible for its transparency and makes up approximately 90% of its thickness?
- Bowman's layer
- Epithelium
- Stroma (Correct answer)
- Descemet's membrane
Correct answer: Stroma
The stroma consists of regularly arranged collagen lamellae that give the cornea its optical clarity and comprises about 90% of corneal thickness.
Question 2: What is the name of the junction between the cornea and the sclera?
- Ora serrata
- Limbus (Correct answer)
- Pars plana
- Zonule of Zinn
Correct answer: Limbus
The limbus is the transitional zone where the transparent cornea meets the opaque white sclera.
Question 3: The fovea centralis is located within which structure?
- Optic disc
- Macula lutea (Correct answer)
- Peripheral retina
- Ora serrata
Correct answer: Macula lutea
The fovea centralis is a small depression at the center of the macula lutea that provides the sharpest visual acuity.
Question 4: Which muscle is responsible for depressing and abducting the eye?
- Superior oblique (Correct answer)
- Inferior rectus
- Inferior oblique
- Lateral rectus
Correct answer: Superior oblique
The superior oblique muscle primarily intorts and depresses the eye, with a secondary action of abduction.
Question 5: What type of cells are predominantly found in the fovea?
- Rod photoreceptors
- Cone photoreceptors (Correct answer)
- Ganglion cells
- Bipolar cells
Correct answer: Cone photoreceptors
The fovea contains only cone photoreceptors, which are responsible for high-acuity color vision in bright light.
Question 6: The aqueous humor is produced by which structure?
- Trabecular meshwork
- Schlemm's canal
- Ciliary body (Correct answer)
- Choroid
Correct answer: Ciliary body
The ciliary body's non-pigmented epithelium actively secretes aqueous humor into the posterior chamber.
Question 7: Which cranial nerve innervates the lateral rectus muscle?
- CN III
- CN IV
- CN V
- CN VI (Correct answer)
Correct answer: CN VI
The abducens nerve (CN VI) innervates the lateral rectus, which abducts the eye.
CPOA Ocular Anatomy 2
Which layer of the cornea is responsible for its transparency and makes up approximately 90% of its thickness?