JCAHPO Ocular Anatomy & Physiology 1 — Questions and Answers
Question 1: Which layer of the cornea is responsible for maintaining corneal clarity and regulates fluid transport through active pumping?
- Bowman's layer
- Stroma
- Descemet's membrane
- Endothelium (Correct answer)
Correct answer: Endothelium
The corneal endothelium maintains corneal transparency by actively pumping fluid out of the stroma; loss of endothelial cells leads to corneal edema.
Question 2: The fovea centralis is located in which region of the retina?
- Peripheral retina
- Optic disc
- Macula lutea (Correct answer)
- Ora serrata
Correct answer: Macula lutea
The fovea centralis is the central depression within the macula lutea that contains the highest concentration of cone photoreceptors for maximum visual acuity.
Question 3: Which structure produces the aqueous humor that fills the anterior and posterior chambers of the eye?
- Trabecular meshwork
- Ciliary body (Correct answer)
- Iris
- Schlemm's canal
Correct answer: Ciliary body
The ciliary body's epithelium produces aqueous humor, which flows from the posterior chamber through the pupil into the anterior chamber.
Question 4: The optic nerve is formed by axons of which retinal cells?
- Rods and cones
- Bipolar cells
- Ganglion cells (Correct answer)
- Horizontal cells
Correct answer: Ganglion cells
Retinal ganglion cell axons converge at the optic disc and exit the eye as the optic nerve, transmitting visual information to the brain.
Question 5: What is the primary function of the vitreous humor?
- Nourishing the lens
- Producing aqueous humor
- Maintaining intraocular pressure and eye shape (Correct answer)
- Focusing light onto the retina
Correct answer: Maintaining intraocular pressure and eye shape
The vitreous humor is a gel-like substance filling the posterior segment that provides structural support to maintain the eye's spherical shape.
Question 6: Which extraocular muscle is responsible for intorsion and depression of the eye, and is the only muscle innervated by cranial nerve IV?
- Inferior rectus
- Superior oblique (Correct answer)
- Superior rectus
- Inferior oblique
Correct answer: Superior oblique
The superior oblique muscle, innervated by the trochlear nerve (CN IV), produces intorsion and assists in depression and abduction of the eye.
Question 7: The trabecular meshwork is primarily located in which structure of the eye?
- Angle of the anterior chamber (Correct answer)
- Posterior chamber
- Ciliary sulcus
- Vitreous base
Correct answer: Angle of the anterior chamber
The trabecular meshwork lines the iridocorneal angle of the anterior chamber and is the primary drainage pathway for aqueous humor into Schlemm's canal.
