NBEO- Ocular Physiology
Where are goblet cells most concentrated within the eye? (Choose 2) A) Superior temporal fornix B) Inferonasal fornix C) Temporal bulbar conjunctiva D) Nasal bulbar conjunctiva
B and C
Which of the following occurs in elderly patients? (Choose 2) A) The vertical meridian steepens B) The vertical meridian flattens C) ATR astigmatism is induced D) WTR astigmatism is induced
B and C
Which layers of the cornea can NOT regenerate? (Choose 2) A) Epithelium B) Bowman's layer C) Descemet's membrane D) Endothelium
B and D
Which portion of the inner ear contains the organ of Corti as well as hair cells? A) Vestibule B) Cochlea C) Semi-circular canals
B) Cochlea
What are horizontal saccades controlled by? A) Ipsilateral Frontal eye fields B) Contralateral Frontal eye fields C) Ipsilateral parietal lobe D) Contralateral parietal lobe
B) Contralateral Frontal eye fields
Which of the following is the only blink reflex that does NOT involve input from the frontal lobe? A) Menace reflex B) Dazzle reflex C) Loud noise reflex D) Cotton swab reflex
B) Dazzle reflex
Which wavelength of light is LEAST likely to be absorbed by the cornea or lens? A) 250 nm B) 300 nm C) 350 nm D) 450 nm
D (>400 nm)
Which of the following is NOT true regarding meibomian glands? A) There are approximately 25 located in the upper tarsal plate B) There are approximately 20 located in the lower tarsal plate C) They secrete the lipid layer of the tear film D) They secrete meibum via apocrine secretion
D (Holocrine)
Is the corneal stroma lipophilic or hydrophilic?
Hydrophilic
Is the mucin layer of the tear film hydrophilic or hydrophobic in nature?
Hydrophilic
Is the corneal epithelium hydrophilic or hydrophobic?
Hydrophobic
The majority of sensory nerves found within the cornea are considered ________________ which can detect pain.
Nociceptors
What structure separates the middle ear from the inner ear?
Oval window
Is the Palpebral or Orbital portion of the orbicularis oculi primarily responsible for spontaneous blinking?
Palpebral
Which portion of the orbicularis oculi is responsible for reflex and spontaneous blinking? Palpebral or Orbital?
Palpebral
Is the muscle of Horner part of the Orbital or Palpebral portion of the orbicularis oculi?
Palpebral portion
What structure separates the external ear from the middle ear?
Tympanic membrane
Snow-blindness and welder's keratitis are most likely caused primarily by which form of UV radiation?
UV-C
Is the Vestibule or Semi-circular canals primarily responsible for linear VOR?
Vestibule
Goblet cells primarily need which vitamin in order to function properly?
Vitamin A
Are most topical ophthalmic solutions weak acids or weak bases?
Weak bases
When the eyelid close, which muscle contracts and causes shortening of the canalculi?
muscle of Horner
Benign essential blepharospasm results from spasms of which 3 muscles?
1) Orbicularis oculi 2) Procerus 3) Corrugator
The critical partial pressure of O2 for the cornea is ____________.
10-20 mmHg
The average rate of spontaneous blinking is approximately _______________ blinks per minute.
12-15 blinks per minute
Hypotonic eye drops such as artificial tears can be used to treat dry eye and usually have a osmolarity ~ _______________ mOsm/L.
150 mOsm/L
The eyelid can hold approximately ______________ ul of tears.
30 ul
What is the average osmolarity of the tear film?
308 mOsm
The lacrimal lake can hold approximately _____________ microliters of tears.
7-10 microliters
The entire corneal epithelium with an intact basement membrane replaces itself every _________.
7-14 days
What is the average pH of the tear film?
7.45
Approximately __________% of the tear volume drains through the nasolacrimal system (the rest evaporate).
75%
Complete healing of the basement membrane of the cornea takes approximately ________________ weeks.
8 weeks
A TBUT time < ______________ seconds is considered abnormal?
< 10 seconds
What are the main ions that contribute to tear film osmolarity? (Choose 2) A) Na+ B) HCO3- C) Cl- D) OH-
A and C
Which layers of the cornea can regenerate? (Choose 2) A) Epithelium B) Bowman's layer C) Descemet's membrane D) Endothelium
A and C
Which of the following blink reflexes are caused by CN 2 stimulation? (Choose 2) A) Dazzle B) Cotton swab reflex C) Menace D) Loud noise
A and C
Which of the following increases the release of lipids from meibomian glands? (Choose 2) A) Blinking B) Staring C) Parasympathetic stimulation D) Sympathetic stimulation
A and C
Most topical ophthalmic solutions follow which order of kinetics? A) 1st order B) 2nd order C) 3rd order D) Zero order
A) 1st order
What is the main way that glucose is produced for the cornea? A) Anaerobic glycolysis B) Aerobic glycolysis C) Hexose monophosphate shunt
A) Anaerobic glycolysis (85%)
Which ossicle bone is attached to the tympanic membrane? A) Malleus B) Incus C) Stapes
A) Malleus
What does "Dk" stand for in terms of contact lenses? A) Oxygen permeability of material B) Water content of material C) Transmissibility of material D) Abbe value
A) Oxygen permeability of material
Which of the following is NOT innervated by CN 8? A) Tensor tympani muscle B) Cochlea C) Vestibule D) Semicircular canals
A) Tensor tympani muscle
What is NOT one of the main components of the bony labyrinth of the ear? A) Tympanic membrane B) Cochlea C) Vestibule D) Semicircular canals
A) Tympanic membrane
Which of the following is considered the most external in terms of the ear? A) Tympanic membrane B) Malleus C) Stapes D) Oval window
A) Tympanic membrane
Which portion of the inner ear contains utricles and saccules? A) Vestibule B) Cochlea C) Semi-circular canals
A) Vestibule
Is the majority of glucose required by the lens produced by anaerobic or aerobic glycolysis?
Anaerobic glycolysis
Glucose, Na+, K+, lactoferrin, IgA, Vitamin A, and HCO3- are all found within which layer of the tear film?
Aqueous layer
Which of the following does NOT occur during accommodation? A) Ciliary muscle contracts B) Lens zonule tension increases C) Posterior pole of lens moves back slightly D) Anterior chamber depth decreases E) The lens diameter decreases
B (decreases)
Which of the following is NOT true regarding the lens? A) It receives glucose and oxygen from the aqueous B) The lens diameter increases with accommodation C) It primarily generates glucose via anaerobic glycolysis D) It provides approximately 20D of power to the eye
B (decreases)
Which of the following does NOT occur in the tear film during sleep? A) The tear film becomes more acidic B) There is a smaller concentration of IgA C) The number of H+ ion increases in the tear film D) The tear film pH decreases
B (higher concentration)
What are the two major factors responsible for water transport across the corneal epithelium and endothelium which maintains corneal dehydration? (Choose 2) A) Cl- absorption B) Cl-excretion C) Na+ absorption D) Na+ excretion
B and C
What kind of glands are meibomian glands? A) Apocrine B) Holocrine C) Merocrine
B) Holocrine
What is primarily known to slow healing of the corneal basement membrane by degrading hemidesmosome formation? A) Macrophages B) MMPs C) Eosinophils D) NK cells
B) MMPs
Which of the following is NOT part of a blink reflex innervated by CN V1? A) Miosis B) Mydriasis C) Lacrimation D) Protective blink
B) Mydriasis
__________________ is a normal defense reflex present in about 75% of the population and is characterized by an upwards and outwards rotation of the globe following forced lid closure.
Bell's phenomenon
Vitamin A deficiency results in keratinization of the conjunctiva known as ________________.
Bitot's spots
What is the primary contributor of glucose to the cornea? A) Tear film B) Palpebral conjunctiva C) Aqueous D) Limbal blood vessels
C) Aqueous
Which of the following is NOT one of the main antimicrobial components found within the tear film? A) Lactoferrin B) IgA C) Ascorbic acid D) Lysozyme
C) Ascorbic acid
What is the FIRST step of corneal epithelial wound healing? A) Migration of epithelial cells B) Basal cell mitosis occurs rapidly C) Basal cell mitosis is inhibited
C) Basal cell mitosis is inhibited
Winking is a form of voluntary blinking that requires which muscle contraction? A) Palpebral portion of orbicularis oculi only B) Orbital portion of orbicularis oculi only C) Both the palpebral and orbital portion of the orbicularis oculi D) None of the above
C) Both the palpebral and orbital portion of the orbicularis oculi
Which of the following DECREASES with age in regards to the cornea? A) Light scattering of the cornea B) Basement membrane thickness C) Corneal sensitivity D) Descemet's membrane thickness
C) Corneal sensitivity
Which of the following actions requires contraction of the orbital portion of the orbicularis oculi? A) Dazzle reflex B) Spontaneous blinking C) Forced eyelid closure D) Menace reflex
C) Forced eyelid closure
What are pursuits controlled by? A) Ipsilateral Frontal eye fields B) Contralateral Frontal eye fields C) Ipsilateral parietal lobe D) Contralateral parietal lobe
C) Ipsilateral parietal lobe
What are basal cells in the corneal epithelium derived from? A) Wing cells B) Squamous epithelial cells C) Limbal stem cells D) Conjunctiva epithelial cells
C) Limbal stem cells
Which of the following is NOT a common cause of neurotrophic keratitis? A) Herpes simplex B) Herpes zoster C) SLE D) Stroke E) Diabetes
C) SLE
Which ossicle bone is attached to the oval window? A) Malleus B) Incus C) Stapes
C) Stapes
What does "Dk/t" stand for in terms of contact lenses? A) Oxygen permeability of material B) Water content of material C) Transmissibility of material D) Abbe value
C) Transmissibility of material
The corneal epithelium is most sensitive to radiation from ___________. A) UV-A (315-400 nm) B) UV-B (280-315 nm) C) UV-C (100-280 nm)
C) UV-C (100-280 nm)
The stapedius is a muscle that dampens sound. What innervates the stapedius?
CN 7
The tensor tympani is a muscle that dampens sound and is innervated by which cranial nerve?
CN V3 (mandibular)
_______________ is the state of relative dehydration maintained by the normal cornea that is necessary for transparency and ~ 78% H20.
Corneal deturgescence
Which factor does NOT minimalize light scattering from the cornea in order to allow for optimal transparency? A) Corneal crystallins B) Ascorbate helps absorb free radicals C) Precise spacing of the collagen fibers increases destructive interference D) The cornea is highly vascular which absorbs light
D (avascular)
Which of the following does NOT produce mucin? A) Goblet cells B) Corneal squamous cells C) Conjunctival squamous cells D) Conjunctival cuboidal cells
D (squamous)
Which of the following INCREASES during accommodation? A) Anterior chamber depth B) The lens diameter C) Lens zonule tension D) Anterior curvature of the lens
D) Anterior curvature of the lens
Which of the following cranial nerves is NOT involved in reflex blinking? A) CN 2 B) CN 5 C) CN 8 D) CN 9
D) CN 9
An excess of which ion can lead to jelly bumps on soft contacts? A) Na+ B) HCO3- C) Cl- D) Ca2+
D) Ca2+
Which ophthalmic dye is used to perform a TBUT? A) Lissamine green B) Rose bengal C) Fluress D) Fluorescein
D) Fluorescein
Which of the following does NOT provide innervation to the lacrimal gland? A) Parasympathetic fibers from CN 7 B) Sympathetic fibers C) Sensory nerves of CN V1 D) Sensory nerves of CN V2
D) Sensory of nerves of CN V2
Does aqueous secretion typically increase or decrease as we age?
Decrease
What is the most common cause of mucous fishing syndrome?
Dry eye syndrome
Reflex blinking (Except Dazzle) initially stimulates which lobe of the brain?
Frontal lobe
Which accessory lacrimal gland is most likely to be located within the fornices?
Glands of Krause
What reducing agent acts as the primary protector against oxidative damage in the lens?
Glutathione
What is the main enzyme required in the first step of glycolysis in the lens?
Hexokinase
Is the cornea the thickest in the morning or at night?
In the morning
Is the tear film of a healthy ocular surface hypotonic, hypertonic, or isotonic?
Isotonic
Does the upper eyelid close laterally ----> medially or medially ----> laterally?
Laterally ----> medially
Which layer of the tear film is primarily designed to slow the evaporation of the aqueous layer?
Lipid layer
Is the corneal endothelium lipophilic or hydrophilic?
Lipophilic
Is the corneal epithelium lipophilic or hydrophilic?
Lipophilic
Name the 3 main auditory ossicles found in the middle ear.
Malleus, incus, stapes
Is the Vestibule or Semi-circular canals primarily responsible for angular VOR?
Semi-circular canals
Is there a higher concentration of K+ in the tear film or in blood plasma?
Tear film (4x)
What are the two main accessory lacrimal glands?
Wolfring and Krause
Is the concentration of glucose higher in the tear film or in the aqueous?
aqueous
Does the utricle or saccule primarily detect vertical linear movement?
saccule
Excess glucose in diabetes leads to the accumulation of _____________ within the lens which ultimately leads to early cataract formation.
sorbitol
Sound waves are amplified by the ______________ in the ear. (AKA eardrum)
tympanic membrane
Does the utricle or saccule primarily detect horizontal linear movement?
utricle
