Vision and Ophthalmology Ocular Anatomy and Physiology 1 — Questions and Answers
Question 1: Which layer of the cornea is the primary barrier against infection and fluid loss?
- Bowman's layer
- Descemet's membrane
- Epithelium (Correct answer)
- Stroma
Correct answer: Epithelium
The corneal epithelium serves as the primary physical and chemical barrier protecting the eye from pathogens and fluid loss.
Question 2: What is the approximate volume of the adult human vitreous humor?
- 1 mL
- 2 mL
- 4 mL (Correct answer)
- 6 mL
Correct answer: 4 mL
The vitreous humor occupies approximately 4 mL, making up about 80% of the eye's total volume.
Question 3: The fovea centralis is located within which structure of the eye?
- Optic disc
- Macula lutea (Correct answer)
- Iris
- Ciliary body
Correct answer: Macula lutea
The fovea centralis is a small pit located at the center of the macula lutea, responsible for the sharpest central vision.
Question 4: Which cranial nerve innervates the lateral rectus muscle of the eye?
- CN III
- CN IV
- CN V
- CN VI (Correct answer)
Correct answer: CN VI
Cranial nerve VI (abducens nerve) innervates the lateral rectus muscle, which abducts the eye.
Question 5: Aqueous humor is produced by which ocular structure?
- Choroid
- Ciliary body (Correct answer)
- Trabecular meshwork
- Schlemm's canal
Correct answer: Ciliary body
The ciliary body's non-pigmented epithelium secretes aqueous humor, which maintains intraocular pressure and nourishes avascular structures.
Question 6: What type of photoreceptors are responsible for color vision in bright light?
- Rods
- Cones (Correct answer)
- Ganglion cells
- Bipolar cells
Correct answer: Cones
Cone photoreceptors are concentrated in the fovea and are responsible for color discrimination and high-acuity vision in photopic (bright light) conditions.
Vision and Ophthalmology Ocular Anatomy and Physiology 1
Which layer of the cornea is the primary barrier against infection and fluid loss?