usmle-mcq's-9

<1>A 61-year-old woman with leukemia abruptly develops an intensely
itchy rash. Physical examination demonstrates multiple erythematous patches
of the distal arms and legs, some of which involve the palms and soles.
Some of the patches show central clearing with surrounding erythematous
rings. Which of the following is the most likely diagnosis?
A. Erythema migrans chronicum
B. Erythema multiforme
C. Kaposi's sarcoma
D. Psoriasis
E. Urticaria
Answer
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<2>A 52-year-old woman presents to her physician for a check-up. She is
recovering from a wrist fracture after a fall. Dual energy x-ray
absorptiometry of the hip had shown her to have osteoporosis. She
became menopausal at age 50 and did not begin hormone replacement
therapy because of a strong family history of breast cancer. She
now fears a future hip fracture and would like to begin a bone
loss prevention regime.Which of the following pharmaceutical
agents is most appropriate for this patient?
A. Calcitonin nasal spray
B. Oral conjugated estrogen
C. Raloxifene
D. Tamoxifen
E. Transdermal estradiol
Answer
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<3>A fracture of the humerus neck damages a nerve running around the
humeral neck. After the fracture heals, the patient notices a marked
decrease in his ability to raise his arm over his head. The denervated
muscle arises from which of the following?
A. Acromion alone
B. Clavicle and acromion
C. Clavicle and coracoid
D. Coracoid alone
E. Coracoid and acromion
Answer
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<4>A patient is admitted to a psychiatric hospital after having been picked
up by the police for making inappropriate sexual advances. A detailed
psychiatric interview demonstrates deficits in memory, insight,
judgement, personal appearance, and social behavior. The patient
is witnessed experiencing a possible epileptic seizure. Over a
period of several years, motor findings also develop, including
relaxed, but expressionless facies, tremor, dysarthria,
and pupillary abnormalities. Which of the following tests performed on his cerebrospinal fluid would most likely be diagnostic?
A. CSF glucose
B. FTA-ABS
C. Gram's stain
D. Lymphocyte count
E. Neutrophil count
Answer
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5>A 29-year-old single man seeks psychiatric treatment to help him deal
with difficulties in his personal life. Although the man is a successful
computer programmer, he feels unsatisfied with his interpersonal
relationships. He reports being attracted to several of his female
coworkers, but is "too shy" to talk to them about anything other
than superficial subjects such as the weather. He would like to ask
one of the women out on a date, but is afraid of being rejected.
Which of the following diagnoses is most appropriate?
A. Avoidant personality disorder
B. Borderline personality disorder
C. Dependent personality disorder
D. Narcissistic personality disorder
E. Schizotypal personality disorder
Answer
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<6>A 3-month-old infant presents with a 3-day history of fever, cough,
and poor feeding. On examination, the baby appears ill and has a
temperature of 102 F and a respiratory rate of 32. A chest x-ray
film shows bilateral patchy infiltrates in the lungs. Which of
the following is the most likely etiologic agent?
A. Coronavirus
B. Influenza type A
C. Parainfluenza type 1
D. Respiratory syncytial virus
E. Rhinovirus
Answer
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<7>A 35-year-old male presents to the urologist for an infertility
evaluation. A biopsy of his testis is performed to check sperm
production and maturation. A microscopic section reveals only
a few germ cells near the basal lamina in the seminiferous
tubule. Which of the following cells is the germ cell closest
to the basal lamina in the seminiferous tubule?
A. Primary spermatocyte
B. Secondary spermatocyte
C. Spermatid
D. Spermatogonia
E. Spermatozoa
Answer
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<8>A 30-year-old otherwise healthy woman presents to her physician
with complaints of fatigue and dyspnea. Physical examination reveals
normal breath sounds and the presence of third and fourth heart sounds.
Chest x-ray shows clear lung fields but right ventricular enlargement,
main pulmonary artery enlargement, and "pruning" of the peripheral
vasculature. Electrocardiogram shows right axis deviation and right
ventricular hypertrophy. Left ventricular function appears normal
on echocardiography. Serologic studies show antinuclear antibodies.
Which of the following pathological findings would this patient
also show, either at autopsy or if an appropriate biopsy was taken?
A. Mural thrombus of the right atrium
B. Necrosis and scarring of the left ventricle
C. Plexogenic pulmonary vasculopathy
D. Pulmonary artery stenosis
E. Severe pulmonary fibrosis
Answer
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<9>During an abdominal surgical procedure, the surgeon wishes to locate
the ureter in order to ensure that it is not injured. The ureter may be
found immediately anterior to the origin of the
A. common iliac artery
B. external iliac artery
C. internal iliac artery
D. gonadal artery
E. renal artery
Answer
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<10>A patient with mild congestive heart failure is treated with high-dose
furosemide and diureses 25 pounds of fluid. A complete blood count (CBC)
taken before the diuresis shows an RBC count of 4 million/mm3; a CBC
taken after diuresis shows a RBC count of 7 million/mm3. Which of the
following is the most likely explanation?
A. Cyanotic heart disease
B. Increased erythropoietin
C. Polycythemia vera
D. Relative polycythemia
E. Renal cell carcinoma
Answer
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<11>A newborn male child is noted to have hypospadias. A complete
evaluation determines that the child has no other genitourinary
anomalies. Nonetheless, hypospadias repair will be performed to
prevent which of the following possible sequelae?
A. Bladder exstrophy
B. Hydrocele
C. Phimosis
D. Urachal cysts
E. Urinary tract infection
Answer
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<12>During the passage of an intravenous catheter, numerous endothelial
cells are dislodged from the lining of the popliteal vein. What substance
allows platelet adhesion to the exposed collagen fibers?
A. Factor VIII
B. Factor IX
C. Fibronectin
D. Tissue factor
E. Von Willebrand factor
Answer
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<13>A 57-year-old man presents to the emergency department with a
nosebleed for the past 2 hours. The patient received a prosthetic
heart valve 5 months ago and is currently taking warfarin (7.5 mg per day)
and oral antibiotics. Laboratory evaluation reveals
an INR (international normalized ratio, the ratio of
patient to normal prothrombin times) of 6.4. Which of
the following antibiotics is the patient most likely taking?
A. Ampicillin
B. Cephalexin
C. Nitrofurantoin
D. Norfloxacin
E. Phenazopyridine
Answer
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<14>A 47-year-old woman presents with complaints of nervousness and
increased sensitivity to hot weather. She is diagnosed with
hyperthyroidism and prescribed propylthiouracil. What is
the principal mechanism by which this drug acts?
A. Decreasing the efficacy of TSH binding to the thyroid TSH receptor
B. Decreasing the rate of proteolysis of thyroglobulin
C. Increasing the amount of 3,3',5'-triiodothyronine (reverse T3; rT3)
D. Inhibiting deiodination of thyroxine (T4)
E. Inhibiting the uptake of iodide into the thyroid gland
Answer
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<15>Which of the following neurotransmitters is most important for the
induction of REMsleep?
A. Acetylcholine
B. Dopamine
C. Epinephrine
D. Norepinephrine
E. Serotonin
Answer
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<16>A 37-year-old woman presents with 3 days of progressive joint pain
in her ankles, knees, and wrists. She had three similar episodes
over the past several years. On examination, she has a temperature
of 38.7 C, her blood pressure is 110/70 mm Hg, and her heart rate
is 90/min. She has a diffuse petechial rash over her trunk and extensor
surfaces. Her ankles and knees are swollen, red, and tender with
decreased range of motion, and there is tenderness over the tendon
sheaths of her hands and forearms. Blood cultures are negative.
Aspiration of joint fluid reveals a white cell count of
22,000/mm3 with no visible organisms, but culture on
chocolate agar is positive. Which of the following
is an attribute of the causative organism that allows
it to produce recurrent infections?
A. It is an intracellular pathogen
B. It is resistant to ceftriaxone
C. It is resistant to complement-mediated lysis
D. Its capsule is not immunogenic
E. Its pili undergo antigenic and phase variation
Answer
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<17>The data presented below compares the results of a diagnostic
test in the presence and absence of a disease.
Disease present Disease absent
Positive test 40 5
Negative test 10 95
Total 50 100
The specificity of the test is
A. 0.05
B. 0.40
C. 0.80
D. 0.90
E. 0.95
Answer
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<18>Blood stored in a blood bank tends, with time, to become relatively depleted of 2,3-diphosphoglycerate. What effect does this have on the hemoglobin-oxygen dissociation curve?
A. Shifts the curve to the left, so that the hemoglobin has a decreased oxygen affinity
B. Shifts the curve to the left, so that the hemoglobin has an increased oxygen affinity
C. Shifts the curve to the right, so that the hemoglobin has a decreased oxygen affinity
D. Shifts the curve to the right, so that the hemoglobin has an increased oxygen affinity
E. Does not change the dissociation curve
Answer
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<19>A psychotic, indigent man with a history of multisubstance
abuse has been involuntarily hospitalized for 1 week. Because of
persistent diarrhea, stools are sent for ova and parasites,
revealing numerous granular, spherical, thin-walled cysts
measuring 10-20 mm in diameter. Trichrome stains show up to
four nuclei in most of the cysts. These finding are consistent
with an infection by which of the following organisms?
A. Cryptosporidium parvum
B. Dientamoeba fragilis
C. Entamoeba histolytica
D. Giardia lamblia
E. Isospora belli
Answer
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<20>A child who understands that the volume of a liquid poured out of
a narrow glass remains the same when poured into a wider glass is at
which of Piaget's stages of intellectual development?
A. Concrete operations
B. Formal operations
C. Preoperational
D. Sensorimotor
Answer
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<21>A 4-year-old girl is brought to a specialty clinic by her foster parents because of a limp in her right leg and a serum alkaline phosphatase (ALP) that is 10 times the adult upper limit of normal for the test. The child is withdrawn and clinging to her foster mother. Physical examination is remarkable for a blue-green discoloration of the skin overlying a tender, 3-cm mass on the anterior portion of the right mid-thigh. An x-ray of the right thigh reveals a dense mass within the femur that extends into the surrounding tissue. Which of the following best describes the increased alkaline phosphatase and physical findings in this case?
A. ALP is abnormal for her age and the bone lesion represents an area of aseptic necrosis
B. ALP is abnormal for her age and the bone lesion represents repair of a femoral fracture
C. ALP is abnormal for her age and is unrelated to the bone lesion
D. ALP is normal for her age and the bone lesion is an osteogenic sarcoma
E. ALP is normal for her age and is unrelated to the bone lesion
Answer
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<22>Which of the following drugs antagonizes both the vascular and cardiac
actions of norepinephrine?
A. Atenolol
B. Esmolol
C. Labetalol
D. Metaproterenol
E. Prazosin
Answer
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<23>During surgery to treat an ischioanal abscess, the inferior rectal
nerve is damaged. This nerve is a direct branch of which of the following
nerves?
A. Inferior gluteal nerve
B. Pelvic splanchnic nerve
C. Pudendal nerve
D. Sciatic nerve
E. Superior gluteal nerve
Answer
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<24>A 15-year-old girl is evaluated for failure to begin menstruation.
Physical examination demonstrates short stature and a webbed neck.
Chromosomal analysis demonstrates a lack of one X chromosome. This
patient should be specifically evaluated for which of the following
cardiovascular anomalies?
A. Coarctation of the aorta
B. Dextrocardia
C. Ostium primum septal defect
D. Pulmonary stenosis
E. Tetralogy of Fallot
Answer
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<25>A baby is born with a testicular mass. Histologic sections made of the
homogeneous yellow-white mass after its removal demonstrate
epithelial-lined spaces that have flattened-to-cuboidal epithelial
cells with vacuolated cytoplasm containing eosinophilic, hyaline-like
globules. Scattered structures resembling primitive glomeruli
(endodermal sinuses) are also seen. If appropriate
immunohistochemical stains are performed, the eosinophilic
cytoplasmic globules would most likely contain which of the following?
A. Alpha-fetoprotein
B. Estrogen receptors
C. Human chorionic gonadotropin
D. Human papilloma virus
E. Melanin
Answer
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<26>A surgeon wishes to perform a splenectomy on a patient who has
been in an automobile accident. Before removing the spleen, the
splenic artery and splenic vein are ligated. Within which of the
following peritoneal structures are the splenic artery and vein found?
A. Gastrocolic ligament
B. Gastrosplenic ligament
C. Lesser omentum
D. Splenorenal ligament
Answer
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<27>A 65-year-old woman with a long-standing disease has bone marrow
fibrosis and increased bone remodeling, with bone resorption exceeding
bone formation. She has a history of passing calcium-oxalate kidney
stones. Which of the following lab result profiles would be expected
in the serum of this patient?
Calcium Phosphate PTH
A. decreased decreased increased
B. decreased increased decreased
C. decreased increased increased
D. increased decreased increased
E. increased increased increased
Answer
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<28>Upon examination of a newborn male, a cystic structure is found
in the scrotum. It is determined that there is a hydrocele of the
spermatic cord. Which of the following is the most likely etiology
of this finding?
A. Communication between the epididymis and the tunica vaginalis
B. Failure of the processus vaginalis to form
C. Failure of the processus vaginalis to fuse
D. Incomplete fusion of the processus vaginalis
E. Varicosities of the spermatic vein
Answer
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<29>A Brazilian immigrant is hired at a meat-packing plant, and undergoes
an employment physical. Chest x-ray demonstrates a patchy, bilateral
pneumonia and a lung mass, and he is referred to a specialist. Biopsy
of the mass demonstrates fungal organisms with a few very distinctive
"pilot's wheel" yeast forms. Which of the following is the most likely
diagnosis?
A. Blastomycosis
B. Coccidioidomycosis
C. Histoplasmosis
D. Paracoccidioidomycosis
E. Sporotrichosis
Answer
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<30>A 34-year-old female is brought to the emergency room with severe
muscle cramps and carpopedal spasms. The patient was noted to be extremely
irritable and was complaining of tingling around the mouth and in the hands
and feet. A few hours later, laboratory examination reveals
sodium 140 mEq/L, potassium 4.2 mEq/L, chloride 101 mEq/L,
calcium 6.4 mg/dL, phosphate 5.1 mg/dL,
magnesium 2.4 (normal 1.8-3.8 mg/dL) and alkaline phosphatase 67 U/L. A CT scan of the head shows basal ganglia calcifications. Prolonged QT intervals and T wave abnormalities are noted on electrocardiogram. The history is pertinent for a thyroidectomy two months prior to admission. Which of the following conclusions is most consistent with these data?
A. An increase in dietary vitamin D is warrante
B. Hepatocytes have a low 25-hydroxylase activity
C. Intestinal cells are underexpressing calcium transporter genes
D. Isolated cells from the kidney have high 1-hydroxylase activity
E. The levels of 1,25-dihydroxy vitamin D are normal
Answer
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<31>A 48-year-old man presents to his physician with complaints of dizziness
and fatigue. Physical examination reveals a blood pressure of 130/50 mm Hg
and a heart rate of 100 beats per minute. On examination, the physician
notes a large scar on the patient's abdomen. The man states that he was
severely injured in an automobile accident several years ago, and required
abdominal surgery at that time. Which of the following is the most likely
diagnosis?
A. Arteriovenous fistula
B. Cardiac tamponade
C. Heart failure
D. Hypovolemia
E. Shock
Answer
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<32>A renal pathologist examining the day's kidney biopsies notes that one
biopsy shows amorphous red nodules within the glomerular mesangium in
hematoxylin and eosin stained material. Congo red stain of the biopsy
demonstrates apple-green birefringence of these nodules. These nodules
are most likely to be related to which of the following?
A. Acute urinary tract infection
B. Diabetes mellitus
C. Sarcoidosis
D. Systemic lupus erythematosus
E. Tuberculosis
Answer
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<33>A patient goes to his family doctor complaining of persistent and
severe headaches. His physician diagnoses migraine headaches and prescribes
sumatriptan. What is the mechanism of action of this drug?
A. Dopamine1 agonist
B. GABAB antagonist
C. Muscarinic3 antagonist
D. Non-selective beta antagonist
E. Serotonin1D agonist
Answer
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<34>A 60-year-old man presents to his physician after a routine screening
test indicates hyperlipidemia. Physical examination reveals raised,
irregular, yellow papules in the skin of the soft tissues below the eyes.
Biopsy of these lesions would most likely show which of the following?
A. Benign nevus cells
B. Malignant nevus cells
C. Microscopic blisters
D. Munro microabscesses
E. Multinucleated giant cells
Answer
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<35> Trisomy 21 Normal karyotype
Positive test 100 50
Negative test 100 250
An experimental diagnostic test is developed to noninvasively detect the
presence of trisomy 21, Down's syndrome. The test is administered to a
group of 500 women considered to be at risk for a Down's fetus based on
blood tests. The results of this test are shown above. What is the
sensitivity of this new test?
A. 40%
B. 50%
C. 67%
D. 71%
E. 83%
Answer
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<36>An autopsy is performed on a 60-year-old man who developed progressive
dementia, parkinsonism, and visual hallucinations beginning 5 years prior
to death. Histopathologic examination reveals numerous eosinophilic
intracytoplasmic inclusions within neurons of substantia nigra, limbic
cortex, and basal nucleus of Meynert. These inclusions are immunoreactive
for ubiquitin. Which of the following is the most likely postmortem
diagnosis?
A. Alzheimer disease
B. Amyotrophic lateral sclerosis (ALS)
C. Diffuse Lewy body disease (dementia with Lewy bodies)
D. Parkinson disease
E. Pick disease
Answer
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<37>A 60-year-old factory worker reports to his physician that he can no
longer push heavy boxes across the floor. Upon examination it is noted
that the patient elevates the right shoulder when attempting shoulder
flexion, but shoulder abduction is not impaired. The medial border of
the right scapula is very prominent. Which of the following nerves
innervates the affected muscle?
A. Long thoracic nerve
B. Lower subscapular nerve
C. Musculocutaneous nerve
D. Suprascapular nerve
E. Upper subscapular nerve
Answer
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<38>The American Diabetes Association (ADA) recently lowered the cutoff
value for fasting glucose used in diagnosing diabetes mellitus from
140 mg/dL to 126 mg/dL. This reference interval change would be expected
to produce which of the following alterations?
A. Decrease the test's sensitivity
B. Increase the test's false negative rate
C. Increase the test's negative predictive value
D. Increase the test's positive predictive value
E. Increase the test's specificity
Answer
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<39>An emergency room physician examines a patient who has fallen from a
motorcycle and injured his shoulder. The clinician notices a loss of the
normal contour of the shoulder and a abnormal-appearing depression below
the acromion. Which of the following injuries did the patient most likely
sustain?
A. Avulsion of the coronoid process
B. Dislocated shoulder joint
C. Fracture of the mid shaft of the humerus
D. Fracture of the surgical neck of the humerus
E. Laceration of the axillary branch of the posterior cord
Answer
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<40>A 7-month-old child with failure to thrive is found to have a hemoglobin
of 4.4 g/dL. The peripheral smear shows very small red cells with marked
pallor. It is determined that the child has very low levels of
hemoglobin A, with elevated fractions of hemoglobin A2 and hemoglobin F.
Which of the following underlying mechanisms is most likely related to
the observed findings?
A. Amino acid substitution on b globin
B. Antibody against fetal blood cells
C. Cytoskeletal protein defect
D. Insufficient production of b globin
E. Iron deficiency
Answer
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<41>During a routine pelvic examination, a 20-year-old woman is found to
have an enlarged uterus. Ultrasound studies demonstrate a multiloculated
cystic structure within the uterine cavity, but no baby is identified.
This mass is removed with dilation and curettage of the uterus, and
placental-like tissue is observed during pathologic examination.
Which of the following tumor markers would be most useful in
establishing that residual tumor does not remain in the uterus?
A. b-hCG
B. Bombesin
C. CEA
D. PSA
E. S-100
Answer
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<42>On physical examination of a 7-year-old boy, the child's upper body
appears much more developed than his lower body. Blood pressure in the
upper extremities exceeds that of the lower extremities. On cardiac
examination, there is a midsystolic murmur over the anterior chest
and back. The child's lower extremities are cold, and femoral pulses
are absent. The part of the vascular system that is affected in this
disorder is derived from which of the following embryologic
structures?
A. Bulbus cordis
B. Ductus arteriosus
C. Left horn of sinus venosus
D. Right common cardinal vein
E. Right horn of sinus venosus
F. Third, fourth, and sixth aortic arches
Answer
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<43>A 42-year-old obese woman experiences episodic abdominal pain.
She notes that the pain increases after the ingestion of a fatty meal.
The action of which of the following hormones is responsible for the
postprandial intensification of her symptoms?
A. Cholecystokinin
B. Gastrin
C. Pepsin
D. Secretin
E. Somatostatin
Answer
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<44>A 42-year-old man was in an automobile accident and suffered severe
pelvic trauma. The bulb of the penis and the urethra were torn from the
inferior surface of the urogenital diaphragm. This has allowed urine to
extravasate from the urethra. Into which of the following regions will
the urine flow?
A. Deep perineal space
B. Ischioanal space
C. Rectovesical pouch
D. Retroperitoneal space
E. Superficial perineal space
Answer
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<45>Karyotypic analysis of a spontaneously aborted fetus demonstrates
trisomy of one of the chromosomes. Which chromosome is most likely to
be affected?
A. 8
B. 13
C. 16
D. 18
E. 21
Answer
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<46>At which of the following locations might a penetrating wound to the
heart damage the AV node?
A. Apex of the heart
B. Interatrial septum
C. Interventricular septum
D. Wall of the right atrium
E. Wall of the left atrium
Answer
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<47>A 9-month-old infant is brought to the Health Department to receive
the second dose of OPV (oral polio vaccine) 2 weeks after the first
vaccination. The child has mild diarrhea, so the decision is made to
defer further immunizations. Bacteriologic examination of a stool culture
is unremarkable; however, a small, single-stranded, positive RNA virus is
isolated from the specimen. This same agent was isolated from sewage
effluent the preceding week. The viral isolate was not inactivated by
ether. Which of the following viruses was most likely isolated?
A. Adenovirus
B. Hepatitis C
C. Parvovirus B19
D. Poliovirus
E. Rotavirus
Answer
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<48> The photomicrograph shows a section of synovium from the knee joint
of a patient with rheumatoid arthritis (RA). Which of the following are
the most abundant cells in the inflammatory infiltrate?
A. Eosinophils
B. Langhans type giant cells
C. Lymphocytes and plasma cells
D. Neutrophils
E. Type A and B synovial cells
Answer

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<49>A 54-year-old African-American female patient undergoes a routine
insurance physical examination. Chest x-ray reveals bilateral hilar
masses. Biopsy of the masses shows granulomata, but acid-fast and
fungal stains are negative for organisms. Which of the following
diseases should be suspected?
A. Caroli's disease
B. Raynaud's disease
C. Sarcoidosis
D. Scleroderma
E. Systemic lupus erythematosus
Answer
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<50>A neuroscientist discovers a way to selectively label neural crest
cells in a developing laboratory animal. After birth, he sacrifices the
animal and examines the tissue to search for labeled cells. Which of
the following cell types will contain the label?
A. Astrocytes
B. Ependymal cells
C. Microglia
D. Oligodendroglia
E. Pseudounipolar cells

Answer
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Answers
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1The correct answer is B. The most specific clue in the description is the presence of erythematous patches with central clearing, known clinically as "target lesions," which are associated with erythema multiforme. Both erythema multiforme and its severe, life-threatening version, known as Stevens-Johnson syndrome, are produced by immune complex deposition in dermal blood vessels. In approximately 50% of patients, no specific precipitating cause is identified. In the remainder of patients, however, a variety of causes have been implicated, including certain infections (herpes simplex, enteroviruses, Mycoplasma pneumoniae, Chlamydia, histoplasmosis), drugs (penicillin, sulfonamides, phenytoin, aspirin, corticosteroids, cimetidine, allopurinol, oral contraceptives), neoplasia (leukemia, lymphoma, multiple myeloma, internal malignancy), sarcoidosis, and foods (notably emulsifiers in margarine).
Erythema migrans chronicum (choice A) also produces an annular erythematous rash with central clearing, but usually affects the thigh, groin, and axilla; it is associated with Lyme disease.
Kaposi's sarcoma (choice C) causes purple lesions with no target lesions.
Psoriasis (choice D) causes erythematous plaques with silvery scale but does not produce target lesions.
Urticaria (choice E) causes wheals that are intensely pruritic, but does not produce target lesions.
--------------------------------------------------------------------------------2The correct answer is C. Raloxifene is a selective estrogen receptor modulator that helps prevent osteoporosis by lessening bone resorption and reducing bone turnover. It lowers risk for vertebral fractures by 40% to 50%. It is a bone-preserving alternative for women who prefer to avoid estrogen. Raloxifene does not cause breast pain and may lessen the risk for breast cancer in menopausal women. There is also a favorable effect on LDL and cholesterol.
Calcitonin nasal spray (choice A) is an osteoclastic bone resorption inhibitor that modestly increases bone mineral density and reduces the incidence of vertebral fracture. Although it is an estrogen alternative for bone preservation, its impact on hip fracture is not known. It is also lacks the anti-breast cancer properties of raloxifene.
Oral conjugated estrogen (choice B) and transdermal estradiol (choice E) are not the best choices, as this patient wants to avoid estrogen because of a strong family history of breast cancer. The route of administration of estrogen has been shown to have similar effects on bone preservation, even though the transdermal dosage is generally half that of the oral dosage. Breast cancer risk, however, is slightly increased with the unopposed higher dosage oral estrogen replacement.
Tamoxifen (choice D), while indicated in the long-term care of breast cancer patients, is not alone useful for treatment or prevention of osteoporosis. Tamoxifen is an anti-estrogen agent that competes with estrogen for binding sites.
--------------------------------------------------------------------------------3The correct answer is B. The nerve is the axillary branch of the posterior cord (also called the axillary nerve), which can be damaged by either fracture or dislocations of the humeral neck. The muscle is the deltoid muscle, which is supplied by this nerve. The deltoid arises from the lateral portions of the clavicle and the acromion and inserts into the deltoid tuberosity of the humerus.
The deltoid arises from both the acromion (choice A) and the clavicle.
The deltoid does not arise from the coracoid process (choices C, D, and E).
--------------------------------------------------------------------------------4The correct answer is B. The patient has neurosyphilis, specifically general paresis, a term that means "general paralysis of the insane." In this late sequela of syphilitic infection which occurs 5 to 20 years after infection, patients develop mental deterioration, which precedes motor system deterioration, leading eventually to "general paralysis" with mutism and incontinence. The abnormalities may be conveniently recalled using paresis as a mnemonic for personality, affect, hyperactive reflexes, Argyll Robertson pupils in the eyes, defects in the sensorium, intellectual decline and deficient speech. Specific anti-treponemal tests such as FTA-ABS are usually positive on both serum and cerebrospinal fluid.
The cerebrospinal (CSF) glucose (choice A) in neurosyphilis is usually normal.
Gram's stain (choice C) of CSF will not demonstrate spirochetes in neurosyphilis.
The CSF lymphocyte count (choice D) is typically elevated in neurosyphilis, but this is a non-specific finding.
The CSF neutrophil count (choice E) is usually normal in neurosyphilis.
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5>The correct answer is A. The man described is probably suffering from avoidant personality disorder, characterized by feelings of inadequacy and extreme sensitivity to criticism, leading to social inhibition and withdrawal. These individuals often avoid interpersonal relationships entirely rather than subject themselves to the potential risk of criticism or rejection, although they may yearn for a more satisfying personal life.
Borderline personality disorder (choice B) is characterized by unstable interpersonal relationships, instability of affect, impulsivity, feelings of emptiness or anger and, in some cases, paranoid or dissociative symptoms.
Dependent personality disorder (choice C) is characterized by the need for constant support and reassurance, with unrealistic anxieties over being forced to fend for oneself.
Narcissistic personality disorder (choice D) is characterized by excessive grandiosity and an exaggerated sense of self-importance, accompanied by a feeling of entitlement and a need for attention or admiration.
Schizotypal personality disorder (choice E) is characterized by eccentricities of behavior, odd beliefs or magical thinking, and difficulties with social and interpersonal relationships.

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--------------------------------------------------------------------------------6The correct answer is D. Respiratory syncytial virus is the most common cause of bronchiolitis and pneumonia in children younger than 1 year. Outbreaks occur seasonally in winter and early spring. Infection does not result in lasting immunity, and reinfection can occur.
Coronavirus (choice A) causes the common cold (nasal obstruction and discharge, sneezing, no fever or mild fever, occasional sore throat, and/or cough) and acute pharyngitis (sore throat, with or without cervical adenopathy, ulceration, and conjunctivitis).
Influenza type A (choice B) is the leading cause of influenza. Influenza is a systemic illness characterized by the sudden onset of fever, headache, myalgias, malaise, and prostration, followed by cough, nasal obstruction, and sore throat. The lower respiratory tract may also be involved.
Parainfluenza viruses (choice C) are the leading cause of croup, or acute laryngotracheobronchitis, in children. This infection involves both the upper and lower respiratory tracts. Inflammation in the subglottal area leads to hoarseness, dyspnea, a barking cough, and inspiratory stridor.
Rhinovirus (choice E) is the most common cause of the common cold.
--------------------------------------------------------------------------------7The correct answer is D. Maturation of germ cells (spermatogenesis) within the seminiferous tubules occurs in a concentric pattern with the less mature spermatogonia near the basal lamina and the mature forms near the tubule center. Spermatogonia are 2N cells and mature into larger primary spermatocytes (4N) (choice A). These mature into secondary spermatocytes (2N) (choice B), and finally into spermatids (1N) (choice C). Spermatids undergo spermiogenesis to become mature spermatozoa (choice E). Acrosomes form from the Golgi apparatus and a flagellum forms from microtubules. Unneeded organelles are shed. The seminiferous tubules of a reproductive-age male should exhibit all stages of maturation, with mature flagellated sperm in their centers.
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8The correct answer is C. The presentation described is classic for pulmonary hypertension, and, more specifically, the primary idiopathic form of pulmonary hypertension. This rare condition is suspected of being related to the collagen vascular diseases, since up to 50% of patients have antinuclear antibodies (despite the absence of frank presentation of other autoimmune disease). Also, a similar, known secondary form of pulmonary hypertension is sometimes seen in patients with a wide variety of collagen vascular diseases, including systemic lupus erythematosus, polymyositis, dermatomyositis, systemic sclerosis, and adult and juvenile forms of rheumatoid arthritis. A wide variety of other conditions have also been associated with secondary pulmonary hypertension, including shunts, left atrial hypertension, chronic hypoxia, pulmonary embolism, drug reaction, hepatic cirrhosis, and sickle cell disease. Both primary and secondary forms of pulmonary hypertension are associated with prominent changes in the pulmonary vasculature, which can include muscularization of smaller arterioles, concentric hypertrophy of the intima ("onion skinning"), and a distinctive plexiform lesion (plexogenic pulmonary vasculopathy) in which the smallest arterioles become markedly dilated with lumens partially occluded by endothelial (or possibly mesenchymal) cells and sometimes, thrombus. The prognosis of untreated pulmonary hypertension is poor. However, the use of the vasodilator hydralazine with anticoagulation can slow the course (fatal in about 3 years in untreated patients). If the pulmonary hypertension is secondary, therapy of the primary disease can be helpful.
Unlike cor pulmonale, atrial fibrillation with mural thrombus (choice A) formation is uncommon in primary pulmonary hypertension.
The absence of left ventricular findings on echocardiography tends to exclude myocardial infarction as the source of the patient's findings (choice B).
The presence of enlargement of the main pulmonary artery excludes pulmonary artery stenosis (choice D).
The clear lung fields exclude severe pulmonary fibrosis (choice E).
--------------------------------------------------------------------------------9The correct answer is B. The ureter leaves the renal pelvis and lies on the posterior abdominal wall as it descends to the pelvis. It crosses the pelvic brim at the level of the bifurcation of the common iliac artery. At this point it crosses anterior to the origin of the external iliac artery to enter the pelvis.
The origin of the common iliac artery (choice A) is at the bifurcation of the abdominal aorta, which occurs at the level of the fourth lumbar vertebra in the midline of the abdomen. Both ureters are lateral to the aortic bifurcation.
The origin of the internal iliac artery (choice C) is at the bifurcation of the common iliac artery, which occurs at about the level of the first sacral vertebra. The ureter and the internal iliac artery both enter the pelvis with the ureter on the lateral side of the artery.
The origin of the gonadal artery (choice D) (either the testicular artery or the ovarian artery) is from the abdominal aorta at a variable level, usually between the renal artery and the inferior mesenteric artery. The ureters are lateral to the origin of this artery.
The origin of the renal artery (choice E) is from the abdominal aorta at about the level of the second lumbar vertebra. The renal arteries pass laterally to enter the renal pelvis. At this site, the ureter is posterior to the artery.
--------------------------------------------------------------------------------10The correct answer is D. This is an example of relative polycythemia, in which there is an increased hematocrit or RBC count without a true increase in the total number of body RBCs. What usually happens in these cases is a significant reduction in plasma volume due to processes such as dehydration, vomiting, diarrhea, or diuresis.
Cyanotic heart disease (choice A), via appropriate erythropoietin secretion, can cause secondary absolute polycythemia.
Increased erythropoietin (choice B), whether appropriately or inappropriately secreted, can cause secondary absolute polycythemia.
Polycythemia vera (choice C) causes primary absolute polycythemia with usually low erythropoietin levels.
Renal cell carcinoma (choice E), via inappropriate erythropoietin secretion, can cause secondary absolute polycythemia.
--------------------------------------------------------------------------------11The correct answer is E. Hypospadias, which is congenital displacement of the urethral opening onto the ventral surface (underside) of the penis, is due to malformation of the urethral groove and canal. Hypospadias frequently accompanies other genitourinary anomalies, especially cryptorchidism. Isolated hypospadias is repaired because the abnormal opening is often constricted, leading to urinary retention and ascending urinary tract infections. Another important consequence of hypospadias is sterility, which occurs if the opening is too close to the base of the penis to permit normal ejaculation. Although hypospadias can occur in isolation, it is strongly associated with other urogenital anomalies.
Bladder exstrophy (choice A) is a completely unrelated congenital malformation in which the abdominal wall and anterior bladder wall form incompletely, and the bladder mucosa is exposed to the environment.
Hydrocele (choice B) is a serous accumulation in the tunica vaginalis, often producing a readily apparent scrotal mass. Hydrocele usually arises without any obvious cause.
Phimosis (choice C) is the condition in which the foreskin cannot be retracted over the head of the penis. It is usually either a congenital malformation or a consequence of scarring.
Urachal cysts (choice D) are produced by areas of persistent urachal epithelium, which may be present anywhere between the bladder and the umbilicus.
--------------------------------------------------------------------------------12The correct answer is E. Von Willebrand factor (vWF) is a self-polymerizing clotting protein present in the serum and the subendothelial basal lamina, which has binding sites for collagen, platelets, and fibrin. At a site of injury, vWF forms the bridge between the exposed collagen fibers and platelets in circulation, stimulating platelet degranulation and initiating the cellular component of the clotting cascade. An equally important role for vWF is binding platelets to the newly formed fibrin strands in a blood clot.
Factor VIII (choice A) and Factor IX (choice B) are clotting proteins of the intrinsic pathway. Factor VIII acts in concert with activated Factor IX (IXa) to cleave Factor X to Xa. Xa is the prothrombin activator central to both the intrinsic and extrinsic pathways.
Fibronectin (choice C) is a serum protein that acts as an opsonin for phagocytic cells in clots. Fibronectin binds non-specifically to bacteria and other materials in the newly forming clots, and draws the cell membrane of phagocytes into contact with these substances.
Tissue factor (choice D) is a protein released from injured tissues that works in concert with Factor VII to initiate the extrinsic pathway of coagulation. Like Factors VIII and IX, tissue factor and Factor VII cleave Factor X to Xa.
--------------------------------------------------------------------------------13The correct answer is D. The patient is most likely experiencing a potentiation of the effects of warfarin by norfloxacin, which decreases the metabolism of the warfarin. The increased warfarin effect produces an increase in the INR. (The target INR for patients with prosthetic heart valves is usually 1.5-4, depending on the type of valve.) Although norfloxacin is the most likely drug among the choices given to cause this effect in this patient, the antibiotics most commonly associated with this type of interaction are the macrolides, such as erythromycin, metronidazole, and the sulfonamide antibiotics.
Oral doses of penicillins, such as ampicillin (choice A), are generally not associated with a potentiation of warfarin's effect, although large IV doses of penicillin may be.
Cephalexin (choice B) is a first-generation cephalosporin that can be used in the treatment of acute cystitis. Although this agent is generally not associated with an increased hypoprothrombinemic effect when given with warfarin, the cephalosporins with a methyltetrazolethiol side chain, such as cefazolin, cefmetazole, and cefoperazone, are known to increase warfarin's therapeutic effect.
Nitrofurantoin (choice C) is a urinary anti-infective agent that does not interact with warfarin.
Phenazopyridine (choice E) is a urinary tract analgesic that does not interact with warfarin, although it commonly changes the color of urine to a bright orange/red color, which the patient may mistake as blood in the urine.
--------------------------------------------------------------------------------14The correct answer is D. Propylthiouracil works primarily by inhibiting the peripheral conversion of T4 to T3. The thyroid extracts iodide from the plasma and, in an oxidative process, iodinates tyrosine residues in thyroglobulin molecules. Monoiodotyrosines and diiodotyrosines are formed and then coupled to produce either thyroxine (tetraiodothyronine, T4) or triiodothyronine (T3). Proteolytic cleavage of thyroglobulin molecules leads to free T3 or T4, which is then released into the circulation; T3 is several times more potent than T4. Peripheral deiodination of T4 at the 5' position leads to T3 formation (mainly in the liver); this step is inhibited by propylthiouracil.
Decreasing the efficacy of TSH binding (choice A), decreasing the rate of thyroglobulin proteolysis (choice B), increasing the amount of rT3 formation (choice C), and inhibiting the uptake of iodide into the thyroid (choice E), would all tend to decrease the formation of thyroid hormones in the thyroid itself.
--------------------------------------------------------------------------------15The correct answer is A. Acetylcholine is the neurotransmitter of primary importance for the induction of REM sleep. Some of the other neurotransmitters do function in sleep, but REM sleep can occur in their absence.
Dopamine (choice B) is a neurotransmitter with a role in voluntary movement, mood, cognition, and regulation of prolactin release.
Epinephrine (choice C) is important in sympathetic nervous system responses. It is also a CNS neurotransmitter.
Norepinephrine (choice D) is important in sympathetic nervous system responses. It is also a CNS neurotransmitter involved in attention, arousal, and mood.
Serotonin (choice E) is a CNS neurotransmitter that plays an important role in mood and sensation. In the periphery, it is involved in vascular regulation and digestive function.
--------------------------------------------------------------------------------16The correct answer is E. This is a case of Neisseria gonorrhoeae arthritis. Patients are continuously susceptible to reinfection because of antigenic variation and phase variation of the pili.
N. gonorrhoeae is not an intracellular pathogen (choice A), although it may be found intracellularly in neutrophils after it has been phagocytized.
Ceftriaxone (choice B) is the drug of choice for N. gonorrhoeae.
Gonococci are especially susceptible to complement-mediated lysis, not resistant to it (choice C).
N. gonorrhoeae has an insignificant capsule that does not play a major role in the pathogenesis, but its capsule is immunogenic (compare with choice D). Streptococcus pyogenes is the best known example of a nonimmunogenic capsule, made of hyaluronic acid, but virtually all other capsules are immunogenic.
--------------------------------------------------------------------------------17The correct answer is E. Specificity is the proportion of persons without the disease who are correctly identified by the test as being disease-free. It is given by TN/(FP + TN), where TN stands for true negatives (people who do not have the disease and test negative on the test) and FP stands for false positives (people who do not have the disease but test positive on the test). In this case, 95/(5 + 95) = 95/100 = 0.95.
--------------------------------------------------------------------------------18The correct answer is B. 2,3-diphosphoglycerate (2,3-DPG) is produced in red cells by a variation on the glycolytic pathway, and levels diminish when glycolysis by the red cells slows. The depletion of 2,3-DPG in stored blood causes the hemoglobin dissociation curve to shift to the left, leading to an increase in oxygen affinity. This increase is helpful in the picking up of oxygen by hemoglobin in the lungs, but can be very problematic in the release of oxygen from the blood in tissues. This is not just a theoretical point: considerable effort has been expended in developing improved solutions for storing packed red cells and methods for "restoring" older stored cells so that the 2,3-DPG levels are adequate. In practice, in otherwise reasonably healthy patients, older transfused blood will quickly regenerate 2,3-DPG when placed in the glucose-containing environment of the serum, but even transiently decreased 2,3-DPG levels in a severely compromised patient can be dangerous.
--------------------------------------------------------------------------------19The correct answer is C. Entamoeba are relatively common enteric pathogens that can produce asymptomatic infection or more severe disease characterized by mucosal ulcerations and submucosal spread causing abdominal distress and liquid stools. Stools may show either trophozoite forms or the typical spherical cysts. Several species of Entamoeba are seen, including Entamoeba coli and E. hartmanni. E. histolytica cysts characteristically are spherical in shape, 10-20 mm in diameter, and have granular cytoplasm containing 1, 2, or 4 nuclei.
Cryptosporidium parvum (choice A) infections occur in the immunocompromised population and may cause severe diarrhea. The organism presents as minute (2-5 mm) intracellular spheres or arc-shaped merozoites under normal mucosa, and can be difficult to appreciate by light microscopy. Cysts in the stool are too small (4-5 mm) to be confused with Entamoeba.
Dientamoeba fragilis (choice B) is an intestinal amoeba that also may produce an infectious diarrhea. It does not have a cyst form, and only the trophozoite forms are seen in stools.
Giardia lamblia (choice D) is a flagellate protozoan that infects the stomach and small intestine when contaminated water is ingested. Diagnosis is usually made by examining duodenal contents; however, the stools may contain the oval or elliptical cysts, which are thick-walled and measure 8-14 mm in diameter. Spherical cysts are not seen in Giardia infection.
Isospora belli (choice E) produces self-limited intestinal infections mostly in the tropics, where fever and diarrhea may last weeks to months. The stool-borne cysts are much larger than Entamoeba (30 x 15 mm), are asymetrical, and are typically almond-shaped.
--------------------------------------------------------------------------------20The correct answer is A. The concrete operational stage (age 7-11 years) is defined by the child's awareness of the conservation of volume, which demonstrates that the child is able to reason in a logical way in terms of the physical world. Note that the child does not develop understanding of abstract concepts until he or she has reached the formal operational stage (choice B), at age 11 to adulthood.
The preoperational stage (choice C), ages 2 to 7 years, is associated with significant language development. However, the child has not yet developed the ability to take the perspective of others, and thus the child's thinking tends to remain egocentric.
The sensorimotor stage (choice D) corresponds to ages 0 to 2 years and is characterized by the infant developing increasingly sophisticated sensorimotor skills and behavior patterns.
--------------------------------------------------------------------------------21The correct answer is B. The reference intervals for serum alkaline phosphatase (ALP) and serum phosphate are higher in children than in adults. Growing bone in children requires alkaline phosphatase secreted by osteoblasts and an increase in serum phosphate to provide a proper solubility product ([calcium] x [phosphorus]) for mineralization of bone. However, the normal serum ALP in children is no greater than 5-times the upper limit of normal for adults, hence this patient's ALP is abnormally elevated. The most likely scenario is that the child is a victim of abuse and has suffered a femoral fracture that is healing. Bone repair further increases the serum ALP owing to the increase in osteoblastic activity.
Aseptic necrosis of bone in the leg (choice A) is more likely to occur in the femoral head (Legg-Calve-Perthes disease). This disease is more common in boys than girls and occurs in the 3- to 10-year-old age bracket. Although aseptic necrosis is associated with dense bone formation, it does not extend out into the soft tissue nor would it produce skin discoloration directly over the lesion (due to trauma in this case).
Since the elevation in serum ALP is increased for age and related to the bone lesion, choice C is incorrect.
Since the serum ALP is not normal for the age of this patient, choices D and E are incorrect. Furthermore, osteogenic sarcoma (choice D) does not normally occur in the first decade and favors the metaphysis of the distal femur or proximal tibia
--------------------------------------------------------------------------------22The correct answer is C. Norepinephrine (NE) is an agonist at alpha1-, alpha2- and beta1-receptors. NE exerts its vascular actions via alpha (predominantly alpha1) receptors and its cardiac actions via beta1-receptors. Labetalol is a nonselective antagonist at alpha- and beta-receptors, and therefore, could prevent all actions of NE.
Atenolol (choice A) is a selective beta1 antagonist, and therefore would block only norepinephrine's cardiac effects.
Esmolol (choice B) is a selective beta1 antagonist, and therefore would block only norepinephrine's cardiac effects. Metaproterenol (choice D) is a selective beta2 agonist and so would not block NE's effects.
Prazosin (choice E) is a selective alpha1 antagonist and would therefore block most of norepinephrine's actions in the vasculature, but would not antagonize other effects.
--------------------------------------------------------------------------------23The correct answer is C. The pudendal nerve is a branch of the sacral plexus that exits from the greater sciatic foramen and then enters the lesser sciatic foramen to lie in the pudendal canal on the lateral wall of the ischioanal fossa. The inferior rectal nerve is a branch of the pudendal nerve, which crosses the ischioanal fossa to reach the anal canal where it innervates the external anal sphincter and provides sensory innervation to the area.
The inferior gluteal nerve (choice A), a branch of the sacral plexus, exits through the greater sciatic foramen and innervates the gluteus maximus muscle.
The pelvic splanchnic nerves (choice B) are branches of the second, third, and fourth sacral nerves that carry preganglionic parasympathetic nerves to several pelvic organs.
The sciatic nerve (choice D) is a branch of the lumbosacral plexus that exits through the greater sciatic foramen, then enters the lower limb to innervate muscles of the posterior thigh, the leg, and the foot, and provides sensory innervation to the area as well.
The superior gluteal nerve (choice E) is a branch of the sacral plexus that exits through the greater sciatic foramen and innervates the gluteus medius, gluteus minimus, and tensor fascia latae muscles.
--------------------------------------------------------------------------------24The correct answer is A. The girl has Turner syndrome, which is specifically associated with coarctation of the aorta. Even when coarctation has not been diagnosed in early childhood and the patient appears to be doing well, surgical correction of any significant degree of coarctation is recommended. Uncorrected coarctation can cause death after about age 40 due to a variety of causes, including congestive heart failure, infective aortitis (analogous to infective endocarditis), and hypertension-induced intracranial hemorrhage or rupture of the damaged (pre-coarctation) aorta.
Associate dextrocardia (choice B) with Kartagener syndrome.
Associate ostium primum septal defect (choice C) with Down syndrome.
Pulmonary stenosis (choice D) and tetralogy of Fallot (choice E) are not specifically associated with Turner syndrome.
--------------------------------------------------------------------------------25The correct answer is A. The malignant tumor is a yolk sac tumor, also known as infantile embryonal carcinoma and endodermal sinus tumor. The biggest tip-off in the question stem is the presence of endodermal sinuses that resemble primitive glomeruli. The cytoplasmic globules described contain alpha-fetoprotein, indicating yolk cell differentiation, and alpha-1-antitrypsin. Alpha-fetoprotein can also be used as a serum marker for recurrent disease. Yolk sac tumors occur in pure form in infants and children and may be part of mixed tumors in adults.
Estrogen receptors (choice B) are important markers in breast cancer because they predict tumor response to hormonal manipulation.
Human chorionic gonadotropin (choice C) is found in the syncytial cells of embryonal carcinoma.
Human papilloma virus (choice D) can be found in condylomas, cervical cancer, penile cancer, laryngeal polyps, and warts.
Melanin (choice E) can be found in melanomas.
--------------------------------------------------------------------------------26The correct answer is D. The splenorenal ligament is the portion of the dorsal mesentery between the posterior abdominal wall and the spleen. This mesentery transmits the splenic artery and vein from their retroperitoneal position in the proximal portion of their course to the peritoneal spleen.
The gastrocolic ligament (choice A) is the portion of the greater omentum between the greater curvature of the stomach and the transverse colon. This portion of mesentery is not related to the spleen.
The gastrosplenic ligament (choice B) is the portion of the dorsal mesogastrium between the greater curvature of the stomach and the spleen. There are no splenic vessels in this mesentery.
The lesser omentum (choice C) is derived from the ventral mesentery. It is the mesentery between the lesser curvature of the stomach and the liver and between the first portion of the duodenum and the liver. It is not related to the spleen.
--------------------------------------------------------------------------------27The correct answer is D. This is one of those questions for which having a good idea of what you are looking for before exploring the answer choices will certainly save you valuable time. The answers all look alike and you could have been easily confused if you were not confident of the answer before approaching the choices.
This patient has long-standing hyperparathyroidism (elevated PTH), which predisposes to the development of osteitis fibrosa, her bone disease. PTH acts initially on osteocytes of bone tissue (osteocytic osteolysis) and subsequently on osteoclasts (osteoclastic resorption) to resorb calcium from bone matrix and make it available to the circulation. This increases plasma calcium levels. PTH also causes decreased phosphate reabsorption in the proximal renal tubule, yielding hypophosphatemia. Hypercalciuria is another sequela of excess PTH production, which predisposes the patient to the formation of calcium oxalate stones.
Choices A and E correspond to neither hyper- nor hypoparathyroid states.
Choice B is the profile of hypoparathyroidism. You should have quickly eliminated this choice since the PTH was decreased and you were looking for a profile consistent with HYPERparathyroidism.
Choice C is the profile of secondary hyperparathyroidism. This occurs when there is parathyroid overproduction due to a nonparathyroid cause. By far, the most common cause is chronic renal failure. In such cases, there is decreased calcium absorption since the kidneys are involved in the conversion of 25(OH)D3 to the active form 1,25(OH)D3. The decreased calcium ion level stimulates the parathyroid, leading to elevated PTH levels. Hyperphosphatemia results from diminished renal synthesis of 1,25 dihydroxyvitamin D3, creating further calcium-phosphate imbalance and enhanced PTH production.
--------------------------------------------------------------------------------28The correct answer is D. The processus vaginalis is an evagination of the parietal peritoneum of the abdomen that descends through the inguinal canal before the descent of the testis. Normally, the distal end of this evagination remains patent as the tunica vaginalis and the remainder of the processus vaginalis fuses and becomes fibrous. If a part of the processus vaginalis does not fuse (incomplete fusion), the resulting cystic structure is a hydrocele of the spermatic cord.
A communication between the epididymis and the tunica vaginalis (choice A) will result in the passage of sperm into the epididymis. This is a spermatocele.
Failure of the processus vaginalis to form (choice B) would result in an absence of the tunica vaginalis.
Total failure of the processus vaginalis to fuse (choice C) results in a persistent processus vaginalis. This results in congenital inguinal hernias.
Varicosities of the spermatic cord (choice E) or the pampiniform plexus is termed a varicocele.