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Ocular Anatomy & Physiology Flashcards

7 cards from real ABO 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

  1. The lacrimal gland produces the aqueous component of the tear film. Its secretory activity is stimulated primarily by:

    Answer: Parasympathetic fibers from the facial nerve (CN VII)

    Parasympathetic fibers traveling with the facial nerve (CN VII) via the pterygopalatine ganglion stimulate lacrimal gland secretion.

  2. The retinal blood supply from the central retinal artery nourishes which retinal layers?

    Answer: The inner two-thirds of the retina (inner nuclear layer and inward)

    The central retinal artery supplies the inner two-thirds of the retina (from the nerve fiber layer to the inner nuclear layer), while the outer retina is supplied by the choroid.

  3. Which muscle is the sole abductor of the eye, innervated exclusively by CN VI?

    Answer: Lateral rectus

    The lateral rectus is the only extraocular muscle innervated by the abducens nerve (CN VI) and is the primary abductor of the eye.

  4. What is the approximate normal central corneal thickness in adults?

    Answer: 520-560 microns

    Normal central corneal thickness averages approximately 520-560 microns (about 0.5 mm), which is clinically important for IOP measurement correction.

  5. The scleral spur is a ridge of dense connective tissue that serves as the attachment point for which structure?

    Answer: The ciliary muscle and the posterior portion of the trabecular meshwork

    The scleral spur anchors the ciliary muscle and the posterior trabecular meshwork, and its position is a key gonioscopic landmark.

  6. Which retinal cell type is primarily responsible for initiating the phototransduction cascade in dim light (scotopic vision)?

    Answer: Rod photoreceptors

    Rod photoreceptors contain rhodopsin and are exquisitely sensitive to low light levels, mediating scotopic (dim light) vision.

  7. The Müller cells of the retina perform all of the following functions EXCEPT:

    Answer: Phagocytosis of shed photoreceptor outer segments

    Phagocytosis of shed photoreceptor outer segment discs is performed by the RPE, not Müller cells; Müller cells buffer K+, recycle glutamate, and provide structural support.