Jun LE5 Flashcards
- 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
b. Stroma
- 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
c. Derived from epithelial cells that produce proteins called crystallins
- Which structure is the most anterior extension of the eye’s vascular layer?
a. Ciliary body
b. Cornea
c. Lens
d. Iris
e. Zonule
d. Iris
- 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
c. Ganglion cells
- 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
d. Basilar membrane
- 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
e. The ossicles
- 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
a. Tectorial membrane
- 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 transduc-tion. 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 Na* channels
e. Depolarization of the cell membranes
d. Closing of Na* channels
- During an eye examination a 55-year-old man is found to show intraocular pressure exceeding 40 mm 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 laver
e. Trabecular meshwork
e. Trabecular meshwork
During a boxing match, a 23-year-old fighter sustains a direct blow to the right ear. He presents with dizziness, vertigo, imbalance, nau-sea, 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
b. Scala tympani
- Which of the following accurately describes glucocorticoids?
a. Include the steroid hormone aldosterone
b. Are produced in response to stimulation by ACTH
c. Are produced primarily by the zone glomerulosa
d. Typically enhance the immune response
e. Include the steroid hormone DHEA
b. Are produced in response to stimulation by ACTH
- Pregnant women who have begun labor but in whom this process is no longer progressing are often given an IV injection of Pitocin to stimulate uterine contractions and facilitate parturition. Pito-cin is a trade name of a hormone produced in what endocrine tissue?
a. Pars distalis
b. Ovarian follicles
c. Pars nervosa
d. Placenta
e. Pars tuberalis
c. Pars nervosa
- What hormone is produced in response to decreased blood calcium levels?
a. Pancreatic polypeptide
b. B-endorphin
c. Somatostatin
d. Calcitonin
e. PTH
e. PTH
- Addison disease (or adrenal cortex insufficiency) is a disorder, usually autoimmune in origin, which can cause degeneration and cell loss in the adrenal glands. Fludrocortisone is a mineralocorticoid used to treat Addison patients. Response to this drug indicates that which region of the adrenal glands was involved in the disease?
a. Medulla
b. Zona glomerulosa
c. Zona reticularis
d. Macula densa
e. Zona fasciculate
b. Zona glomerulosa
- A glucagonoma is a malignant tumor consisting of what cells?
a. Aora cells
b. Bor B cells
c. Chromophils
d. D or 8 cells
e. Mucous cells
a. Aora cells