Ocular Anatomy & Physiology Flashcards
7 cards from real JCAHPO practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Ocular Anatomy & Physiology flashcards as text
Which cranial nerve provides sensory innervation to the cornea and is responsible for triggering the blink (corneal) reflex?
Answer: Cranial nerve V (trigeminal)
The ophthalmic branch (V1) of the trigeminal nerve (CN V) provides sensory innervation to the cornea; afferent signals from corneal touch trigger the blink reflex.
The tear film is composed of three layers. Which layer, produced by goblet cells, is the innermost and provides adhesion to the corneal epithelium?
Answer: Mucin layer
The mucin layer, secreted by conjunctival goblet cells, forms the innermost layer of the tear film and converts the hydrophobic corneal surface to hydrophilic for tear adhesion.
The choroid is primarily responsible for which function?
Answer: Supplying oxygen and nutrients to the outer retina
The highly vascular choroid provides the majority of oxygen and nutrients to the outer retinal layers, including photoreceptors, through diffusion.
Accommodation of the lens for near vision involves which action of the ciliary muscle?
Answer: Ciliary muscle contracts, zonules relax, lens becomes more convex
When the ciliary muscle contracts, it reduces tension on the zonular fibers, allowing the elastic lens capsule to make the lens more spherical and increase its refractive power for near focus.
The cornea derives most of its oxygen supply from which source?
Answer: Atmospheric oxygen dissolved in tears
The avascular cornea receives approximately 80% of its oxygen directly from atmospheric oxygen dissolved in the precorneal tear film, with some supplemental supply from aqueous humor and limbal vessels.
Which structure is responsible for draining aqueous humor from Schlemm's canal into the episcleral venous system?
Answer: Collector channels
Collector channels (aqueous veins) drain aqueous humor from Schlemm's canal into the episcleral and conjunctival veins, completing the aqueous outflow pathway.
The dilator pupillae muscle, which enlarges the pupil in dim light, is innervated by which nervous system pathway?
Answer: Sympathetic via the superior cervical ganglion
The dilator pupillae is innervated by sympathetic fibers originating in the hypothalamus, synapsing in the superior cervical ganglion, and traveling along the internal carotid artery to the eye.