Jun LE5

Question 1

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

b. Stroma

Question 2

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

c. Derived from epithelial cells that produce proteins called crystallins

Question 3

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

d. Iris

Question 4

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

Answer 4

c. Ganglion cells

Question 5

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

Answer 5

d. Basilar membrane

Question 6

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

Answer 6

e. The ossicles

Question 7

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

Answer 7

a. Tectorial membrane

Question 8

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 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

Answer 8

d. Closing of Na* channels

Question 9

9. 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

Answer 9

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, 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

Answer 10

b. Scala tympani

Question 11

1. 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

Answer 11

b. Are produced in response to stimulation by ACTH

Question 12

2. 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

Answer 12

c. Pars nervosa

Question 13

3. What hormone is produced in response to decreased blood calcium levels?
   a. Pancreatic polypeptide
   b. B-endorphin
   c. Somatostatin
   d. Calcitonin
   e. PTH

Answer 13

e. PTH

Question 14

4. 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

Answer 14

b. Zona glomerulosa

Question 15

5. 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

Answer 15

a. Aora cells

Question 16

6. Secretion, chemical modification and storage, reuptake, and digestion of a protein occur in epithelial cells of what endocrine tissue?
   a. Neurohypophysis
   b. Adrenal medulla
   c. Adenohypophysis
   d. Thyroid gland
   e. Neuroendocrine cells in the duodenum

Answer 16

d. Thyroid gland

Question 17

7. Secretion in what neuroendocrine cell is controlled directly by neural activity and involves a hormone that generally slows metabolic activity at night?
   a. Pituicyte
   b. Melanocyte
   c. Herring body of the neurohypophysis
   d. Chromaffin cell
   e. Pinealocyte

Answer 17

e. Pinealocyte

Question 18

8. Some mammalian endocrine tissues or cells can be experimentally transplanted to other well-vascularized sites (such as the oral mucosa) in genetically similar hosts and the tissues function continues normally and with proper regulation. The pars distalis is not a good candidate for such transplantation studies for which one of the following reasons?
   a. More severe rejection of neurally related tissue occurs compared with other endocrine organs.
   b. Its hormonal source is unavailable after its axonal connections to the hypothalamus are disrupted.
   c. Its cells stop functioning when separated from the hypothal-amo-hypophyseal portal system.
   d. Neogenesis of blood vessels into this tissue will not occur at the transplant site.
   e. The vascular wall of the superior hypophyseal arteries is unique.

Answer 18

c. Its cells stop functioning when separated from the hypothal-amo-hypophyseal portal system.

Question 19

9. A 45-year-old corporate executive presents with the primary complaint of “always being tired” She comments that she has been tired for 4 months even though she is sleeping more. She complains of being unable to finish chores at home and “dragging at work” She indicates that she is often constipated and is intolerant of cold. She is continuously turning the thermostats in the house and office to higher temperatures, to the dismay of family and coworkers. She also complains that her skin is very dry; use of lotions and creams have not helped the dryness. A biopsy of her thyroid gland shows dense lymphocytic infiltration with germinal centers throughout the parenchyma and a battery of further tests is carried out, which also suggest thyroiditis. Which of the following results of blood tests would be most likely in this patient?
   a. Elevated TSH levels
   b. Elevated I, and I, levels
   c. Autoantibodies to the thyroid hormone receptor
   d. Elevated calcitonin levels
   e. Elevated glucocorticoid levels

Answer 19

a. Elevated TSH levels

Question 20

10. A 9-year-old girl, the youngest of four daughters, is taken to the pediatrician by her mother, who indicates that for at least 4 months the child has seemed “hyperactive” unable to sleep soundly because
    “she says her room is too hot, and no longer able to concentrate in school. Upon questioning, the mother also remembers that her daughter’s periods also began within the past few months. Blood tests indicate high levels of estrogen-related hormones and cortisol.
    Which of the following tentative diagnoses is consistent with all of these symptoms?
    a. Graves disease, caused by antibodies stimulating the ISH receptor
    b. A defect in the PVN
    c. Excessively active cells of the adrenal cortex zona glomerulosa
    d. A benign tumor involving cells in the adenohypophysis
    е. A disabling mutation in the gene for thyroglobulin

Answer 20

d. A benign tumor involving cells in the adenohypophysis

Question 21

1. Blood in the renal arcuate arteries flows next into which vessels?
   a. Afferent arterioles
   b. Efferent arterioles
   c. Glomerular capillaries
   d. Interlobar arteries
   e. Interlobular arteries

Answer 21

e. Interlobular arteries

Question 22

2. Which cell type comprises the visceral layer of Bowman capsule?
   a. Endothelial cells
   b. Juxtaglomerular cells
   c. Mesangial cells
   d. Podocytes
   e. Extraglomerular mesangial (or Lacis) cells

Answer 22

d. Podocytes

Question 23

3. Which type of epithelium lines the thick ascending limb of the loop of Henle?
   a. Pseudostratified columnar
   b. Simple columnar
   c. Simple cuboidal
   d. Simple squamous
   e. Transitional (urothelium)

Answer 23

c. Simple cuboidal

Question 24

4. Which cell is a modified smooth muscle cell that secretes renin?
   a. Macula densa cells
   b. Mesangial cells
   c. Podocytes
   d. Juxtaglomerular cells
   e. Endothelial cells

Answer 24

d. Juxtaglomerular cells

Question 25

5. Epithelial cell membrane domains containing many stiffened plaques of protein are an important feature in which part of the urinary system? a. Juxtaglomerular apparatus b. Bladder mucosa c. Collecting ducts d. Renal pyramids e. Membranous urethra

Answer 25

b. Bladder mucosa

Question 26

6. An immunohistochemical technique using antibodies against aquaporins to stain a section of kidney would be expected to stain cells in which structures most intensely? a. Collecting ducts b. Lining of the major and minor calyces c. Proximal convoluted tubules d. Distal convoluted tubules e. Glomeruli

Answer 26

a. Collecting ducts

Question 27

7. What type of epithelium lines the prostatic urethra? a. Simple columnar b. Pseudostratified columnar c. Stratified squamous d. Simple squamous e. Transitional (urothelium)

Answer 27

e. Transitional (urothelium)

Question 28

8. A 14-year-old patient presents in the nephrology clinic with fatigue, malaise, anorexia, abdominal pain, and fever. She reports a loss of 6 lb in the past 2 months. Serum gamma globulin and the immunoglobulins IgG, IgA, and IgM are all elevated. Her serum creatine is 1.4 mg/dL (normal 0.6-1.2 mg/dL) and urinalysis of glucose and protein are 2+ on a dipstick test, confirmed by laboratory at 8.0 g/ dL and 0.95 g/dL, respectively. A renal biopsy is prepared for light microscopy, and an infiltrate containing lymphocytes, plasma cells, and eosinophils is found among tubules having cells with prominent brush borders. Which one of the following statements correctly pertains to these epithelial cells? a. Impermeable to water despite presence of ADH b. 'The primary site for the reduction of the tubular fluid volume c. The site of the countercurrent multiplier d. The site of action of aldosterone e. Indirectly involved in the release of renin

Answer 28

b. 'The primary site for the reduction of the tubular fluid volume

Question 29

9. A 45-year-old man presents with nephrolithiasis or kidney stones. The process of calcium oxalate stone formation as seen in this patient begins with Randall plaques found in the basement membranes of which one of the following structures found only in the renal medulla? a. Proximal convoluted tubules b. Distal convoluted tubules c. Thin loops of Henle d. Afferent arterioles e. Collecting ducts

Answer 29

e. Collecting ducts

Question 30

10. A 15-year-old male presents with hematuria, hearing loss, lens dislocation, and the onset of cataracts. Genetic analysis reveals a mutation in the COL4A5 gene. Transmission EM examination of a renal biopsy confirms that the disorder has affected a component of the renal corpuscles in which damage disrupts normal glomerular filtration. Which one of the following structures would most likely be abnormal in the TEM of this patient's biopsy? a. Pedicels b. Filtration slits c. Slit diaphragms d. Glomerular basement membranes e. Fenestrated endothelium of glomerular capillaries

Answer 30

d. Glomerular basement membranes