1.
. A 55-year-old woman presents
with pain in her right hip and thigh. The pain started approximately six months
ago and is a deep ache that worsens when she stands or walks. Your examination
reveals increased warmth over the right thigh. The only laboratory
abnormalities are alkaline phosphatase 656 IU/L (normal 23 to 110 IU/L),
elevated 24-h urine hydroxyproline, and osteocalcin 13 ng/mL (normal 6 ng/mL).
X-ray of hips and pelvis shows osteolytic lesions and regions with excessive
osteoblastic activity. Bone scan shows significant uptake in the right proximal
femur. Which of the following should you include in your differential
diagnosis?
A. 
B. 
C. 
D. 
E. 
2.
A 66-year-old man with no
previous significant illness presents with back pain. The patient had felt well
except for an increase in fatigue over the past few months. He suddenly felt
severe low back pain while raising his garage door. Physical examination
reveals a well-developed white male in acute pain. His pulse is 88 beats per
minute and blood pressure is 150/90 mmHg. The conjunctivae are pale. There is
marked tenderness to percussion over the lumbar spine. The following laboratory
data are obtained: hemoglobin 11.0 g/dL (normal 13 to 16 g/dL), serum calcium
12.3 mg/dL (normal 8.5 to 11 mg/dL), abnormal serum protein electrophoresis
with a monoclonal IgG spike, urine positive for Bence Jones protein, and
abnormal plasma cells in bone marrow. X-rays reveal lytic lesions of the skull
and pelvis and a compression fracture of lumbar vertebrae. Which of the
following is the most likely diagnosis?
A. 
B. 
C. 
D. 
E. 
3.
A 46-year-old woman presents
with a pain in the left leg that worsens on weight-bearing. An x-ray shows
demineralization and a decalcified (EDTA-treated) biopsy shows reduction in
bone quantity. The patient had undergone menopause at age 45 without estrogen
replacement. She reports long-standing diarrhea. In addition, laboratory tests
show low levels of 25-hydroxyvitamin D, calcium, and phosphorus and elevated
alkaline phosphatase. A second bone biopsy, which was not decalcified, shows
uncalcified osteoid on all the bone surfaces. On the basis of these data, which
of the following is the most likely diagnosis?
A. 
B. 
C. 
D. 
E. 
4.
DiGeorge syndrome is a
congenital malformation in which the embryologic derivatives of the third and
fourth branchial pouches fail to form. Which of the following would be expected
to occur in children with this syndrome?
A. 
Absence of the parafollicular cells
B. 
Increased numbers of cells in the deep cortex of the lymph nodes
C. 
D. 
Excess activity of osteoclasts
E. 
Increased Ca2+ levels in the blood
5.
This electron micrograph is a preparation from
bone matrix in close proximity to the cellular components. Which of the
following statements is true in regard to these structures?
A. 
They contain type I collagen
B. 
They are absent during endochondral bone formation
C. 
They bud off from osteoclasts
D. 
They may serve a "seed crystal" function in developing bone
E. 
They contain acid phosphatase
6.
The multinucleate arrangement of skeletal muscle
during development is produced by which of the following?
A. 
Duplication of DNA in myoblasts without cytokinesis
B. 
Fusion of mononucleate myoblasts
C. 
Cell proliferation of myotubes
D. 
E. 
Satellite cell differentiation
7.
Observation of a histologic preparation of
muscle indicates the cross-striations and peripherally located nuclei. The use
of histochemistry shows a strong staining reaction for succinic dehydrogenase.
The same tissue prepared for electron microscopy shows many mitochondria in rows
between myofibrils and underneath the sarcolemma. Which of the following is the
best description of this tissue?
A. 
B. 
Fibers that contract rapidly but are incapable of sustaining continuous heavy work
C. 
D. 
E. 
8.
. In muscular dystrophy, the
actin-binding protein dystrophin is absent or defective. Dystrophin contains
similar actin-binding domains to the spectrins (I and II) and -actinin and has a similar
function. Which of the following is most likely to occur as a result of this
deficiency?
A. 
Deficiency in skeletal muscle actin synthesis
B. 
Enhanced smooth muscle contractility
C. 
Loss of binding of the I and M bands to the cell membrane
D. 
Loss of organelle and vesicle transport throughout the muscle cell
E. 
Loss of integrity of the desmosomal components of the intercalated discs of cardiac muscle
9.
In the accompanying transmission electron
micrograph of striated muscle, which of the following is true of the zone
labeled "C"?
A. 
The sarcomere is defined as the distance between these two structures
B. 
Thin filaments are anchored to this structure
C. 
This structure bisects the H band and is formed predominantly of creatine kinase
D. 
No overlap of thick and thin filaments occurs in this zone
E. 
This portion of the A band consists solely of the rodlike portions of myosin
10.
. In the histogenesis of the neural tube, which
zone will become the white matter of the adult CNS?
A. 
B. 
C. 
D. 
E. 
11.
The neurons shown in the accompanying
photomicrograph of a dorsal root ganglion have which of the following
functions?
A. 
Transmission of autonomic information
B. 
Transmission of proprioceptive information
C. 
Innervation of striated muscle
D. 
Transmission of dental pain
E. 
Transmission of visual stimuli
12.
. The blood-brain barrier is
formed by which of the following?
A. 
Fenestrations between brain capillary endothelial cells
B. 
Occluding junctions between brain capillary endothelial cells
C. 
Astrocytic foot processes surrounding blood vessels entering the brain parenchyma
D. 
The basement membrane associated with the glia limitans
E. 
13.
In the photomicrograph below of tissue taken
from the central nervous system, which of the following are the predominant
cells?
A. 
B. 
C. 
D. 
E. 
14.
The neural crest gives rise to
which of the following?
A. 
Zona glomerulosa of the adrenal gland
B. 
C. 
D. 
E. 
Sensory neurons of the cranial ganglia
15.
Which of the following is the structure
indicated by the arrow?
A. 
B. 
C. 
D. 
E. 
16.
The venous sinuses are located
in which of the following regions?
A. 
B. 
C. 
D. 
E. 
17.
Which of the following
structures best represents the large endothelial pores defined in physiologic
studies?
A. 
B. 
C. 
D. 
E. 
18.
Anionic proteins, such as
insulin and transferrin, cross capillary endothelial cells primarily via which
of the following?
A. 
Diffusion through the membrane
B. 
C. 
D. 
E. 
Vesicular and channel pathways
19.
Organs such as the brain and
thymus have a more effective blood barrier because they have what type of blood
capillaries?
A. 
Continuous type with few vesicles
B. 
Fenestrated type with diaphragms
C. 
Fenestrated type without diaphragms
D. 
Discontinuous type with diaphragms
E. 
Discontinuous type without diaphragms
20.
Atherosclerosis is usually
initiated by which of the following?
A. 
Proliferation of smooth muscle cells
B. 
Formation of an intimal plaque
C. 
Attraction of platelets to collagen microfibrils
D. 
Adventitial proliferation
E. 
Injury to the endothelium
21.
Thrombocytopenia is a
reduction in the number of circulating blood platelets. Which of the following
would most likely occur in thrombocytopenia?
A. 
Decreased vascular permeability
B. 
Failure of initiation of the blood-clotting cascade
C. 
Failure of conversion of fibrinogen to fibrin
D. 
E. 
22.
Which of the following is the structure
labeled A in the photomicrograph below?
A. 
B. 
C. 
D. 
E. 
23.
Anaphylactic shock is
primarily due to the action of which of the following?
A. 
B. 
C. 
D. 
E. 
24.
Expression of antigen
associated with class I major histocompatibility complex (MHC) molecules is
recognized primarily by which of the following?
A. 
B. 
C. 
D. 
E. 
25.
Immunoglobulin switching from IgM to IgG
occurs primarily in which of the following sites?
A. 
B. 
C. 
D. 
E.