Vision and Ophthalmology Ocular Anatomy and Physiology 2 — Questions and Answers
Question 1: Which layer of the retina contains the cell bodies of the rod and cone photoreceptors?
- Inner nuclear layer
- Outer nuclear layer (Correct answer)
- Ganglion cell layer
- Inner plexiform layer
Correct answer: Outer nuclear layer
The outer nuclear layer contains the nuclei (cell bodies) of both rod and cone photoreceptors.
Question 2: The blood-retinal barrier is maintained primarily by which cells?
- Müller cells
- Astrocytes
- Retinal pigment epithelium (Correct answer)
- Pericytes
Correct answer: Retinal pigment epithelium
The retinal pigment epithelium (RPE) forms the outer blood-retinal barrier via tight junctions between cells.
Question 3: The optic chiasm is located above which structure at the base of the brain?
- Pituitary gland (Correct answer)
- Hypothalamus
- Pons
- Cerebellum
Correct answer: Pituitary gland
The optic chiasm sits directly above the pituitary gland (sella turcica), which is why pituitary tumors commonly cause bitemporal visual field defects.
Question 4: Normal intraocular pressure (IOP) in adults ranges from approximately:
- 5–10 mmHg
- 10–21 mmHg (Correct answer)
- 22–30 mmHg
- 30–40 mmHg
Correct answer: 10–21 mmHg
Normal IOP is generally considered to be between 10 and 21 mmHg, with values above 21 mmHg considered elevated.
Question 5: Which structure controls the diameter of the pupil by constricting it?
- Dilator pupillae
- Sphincter pupillae (Correct answer)
- Ciliary muscle
- Superior tarsal muscle
Correct answer: Sphincter pupillae
The sphincter pupillae muscle, innervated by parasympathetic fibers via CN III, constricts the pupil (miosis).
Question 6: Which zone of the lens contains the oldest, most compacted fibers?
- Cortex
- Nucleus (Correct answer)
- Epithelium
- Capsule
Correct answer: Nucleus
The lens nucleus contains the oldest fiber cells, which become increasingly compressed and hardened with age, contributing to presbyopia.
Vision and Ophthalmology Ocular Anatomy and Physiology 2
Which layer of the retina contains the cell bodies of the rod and cone photoreceptors?