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.
JCAHPO Ocular Anatomy & Physiology 1
Which layer of the cornea is responsible for maintaining corneal clarity and regulates fluid transport through active pumping?