Deck 23: The Eye Ear:special Senseorgans

Question 1

Which of the following is the thickest component of the cornea?

A) Corneal epithelium
B) Stroma
C) Descemet membrane
D) Bowman membrane
E) Corneal endothelium

Answer 1

Stroma

Question 2

Which description is accurate for lens fibers?

A) Are terminally differentiated fibroblasts
B) Consist of specialized type I collagen
C) Derived from epithelial cells that produce proteins called crystallins
D) Consist of type III collagen
E) Have the same embryonic origin as the neural retina

Answer 2

Derived from epithelial cells that produce proteins called crystallins

Question 3

Which structure is the most anterior extension of the eye's vascular layer?

A) Ciliary body
B) Cornea
C) Lens
D) Iris
E) Zonule

Answer 3

Iris

Question 4

Which cells transmit visual signals from the retina to the brain?

A) Bipolar cells
B) Amacrine cells
C) Ganglion cells
D) Horizontal cells
E) Müller cells

Question 5

The epithelial cells within the organ of Corti are supported by which of the following structures?

A) Spiral limbus
B) Tectorial membrane
C) Vestibular membrane
D) Basilar membrane
E) Spiral ligament

Question 6

The middle ear contains which of the following structures?

A) The labyrinth
B) The modiolus
C) The perilymph
D) The vestibular apparatus
E) The ossicles

Question 7

Which structure in the cochlea is analogous in composition and function to the cupola of each semicircular canal?

A) Tectorial membrane
B) Pillar cells
C) Inner tunnel
D) Saccule
E) Spiral ganglion

Question 8

A 47-year-old woman is referred to an ophthalmologist after reporting increased difficulty with tasks at night or in dark places for the past 3 or 4 years. She has trouble walking in dimly lit rooms and the movie theater. She has given up driving at night and describes a prolonged adaptation period going from light to dark. She also describes her daylight vision as "tunneled," as she frequently walks into furniture. A family history indicates that her father had a similar condition. In this disease, a single point mutation in the rhodopsin gene leads to disruption of signal transduction. Visual transduction in the affected cells involves which of the following?

A) Inactivation of phosphodiesterase
B) Increase in cGMP levels
C) Conversion of all-trans-retinal to 11-cis-retinal
D) Closing of $\mathrm{Na}^{+}$ channels
E) Depolarization of the cell membranes

Question 9

During an eye examination a 55-year-old man is found to show intraocular pressure exceeding $40 \mathrm{~mm} \mathrm{Hg}$ and blockage of fluid flow within the eye is suspected. Such a diagnosis would involve a blockage at which of the following sites?

A) Choroid body
B) Vessels at the optic disk
C) Pupillary junction of the posterior and anterior chambers
D) Choroid layer
E) Trabecular meshwork

Question 10

During a boxing match, a 23-year-old fighter sustains a direct blow to the right ear. He presents with dizziness, vertigo, imbalance, nausea, vomiting, tinnitus, and fullness in the ears. His vertigo increases with activity and is relieved by rest. He has some hearing loss. The symptoms worsen with coughing, sneezing, or blowing his nose, as well as with exertion. He is diagnosed with perilymphatic fistula, which allows leakage of perilymph. In which of the following structures is perilymph normally found?

A) Scala media
B) Scala tympani
C) Semicircular canals
D) Saccule
E) Utricle