USMLE PRACTICE STUDY QUESTIONS
AND ANSWERS
What are the two major microtubular motor proteins? Which
does anterograde axonal transport, which does retrograde
axonal transport? - CORRECT ANSWER-Kinesin, Dynein
Kinesin: Anterograde
Dynein: Retrograde`
What do you think, immunologically spea...
What are the two major microtubular motor proteins? Which
does anterograde axonal transport, which does retrograde
axonal transport? - CORRECT ANSWER-Kinesin, Dynein
Kinesin: Anterograde
Dynein: Retrograde`
What do you think, immunologically speaking, when you see
someone with recurrent Neisseria infections? - CORRECT
ANSWER-Inability to form the membrane attack (MAC)
complex
this is a common complement deficiency
What is the defect in Chronic Granulomatous disease? What is
the pathophysiology? - CORRECT ANSWER-NADPH Oxidase
deficiency leads to the inability to kill intracellular organisms
Characteristic triad of ataxia telangiectasia? - CORRECT
ANSWER-cerebellar ataxia, telangiectasias, increased risk of
sinopulmonary infections
What is the major immune deficiency of ataxia telangiectasia? -
CORRECT ANSWER-IgA deficiency, which predisposes to
,infections of the upper and lower airways (and other mucous
membranes)
There's a useful mnemonic for Ataxia Telangiectasia and the
gene that's mutated. What is it? - CORRECT ANSWER-ATM
Ataxia
Telangiectasia
Mutated
ATM gene is responsible for DNA break repair
What is one reason that lead intoxication causes hypochromic
anemia? - CORRECT ANSWER-Mitochondrial iron transport is
important for Heme synthesis! It's inhibited by lead. So you
don't make heme in your mitochondria and you get
hypochromic anemia.
What is the biochemical problem in Lesch-Nyhan syndrome?
(And, only if you got that right, what are the really cool
symptoms of it?) - CORRECT ANSWER-Defective purine
catabolism, so buildup of purines. It's an X-linked recessive
disorder with mutated HGPRT gene (hypoxanthine-guanine
phosphoribosyltransferase, if you want to impress people).
Now, if you got HGPRT and purine catabolism right, you can
say: self-mutilating behavior on top of mental retardation,
choreoathetoid (think Chorea) movements and spasticity.
What is the defect in Niemann-Pick disease?
What causes that?
What is the common macular finding? - CORRECT ANSWER-
Sphingolipid degradation is defective
Caused by an autosomal recessive defect in sphingomyelinase
Cherry Spot on the macula? Niemann Pick's or Tay Sach's.
,If a baby gets exposed to an unclean knife (...) and
subsequently develops rigid paralysis, what is the diagnosis,
where do we think this might happen, and how do we prevent
it? - CORRECT ANSWER-Neonatal Tetanus
Developing Countries
Maternal immunization with tetanus toxoid is the best way to
prevent it
an adeuately immunized mom will transfer IgG's across the
placenta to the neonate
Which microtubule associated protein aids in anterograde
transport of intracellular vesicles and organelles? Which end of
the microtubule do they go towards? - CORRECT ANSWER-
Kinesin.
Towards the (+) rapidly growing end.
What is an early BRAIN finding of Ataxia-Telangiectasia and
how does it manifest itself? - CORRECT ANSWER-Cerebellar
atrophy
manifests as ataxia in the first years of life.
High yield path association for Alzheimer's disease? -
CORRECT ANSWER-Neurofibrillary tangles in the neocortex
High yield path association for Parkinson's disease? -
CORRECT ANSWER-Loss of neurons in the substantia nigra
High yield path association for Huntington disease? -
CORRECT ANSWER-Atrophy of caudate nucleus
What are the major manifestations of Ataxia-telangiectasia? -
CORRECT ANSWER-cerebellar ataxia, oculocutaneous
tenlangiectasias, repeated sinopulmonary infections, and an
increased incidence of malignancy
, If you heard: amenorrhea, bitemporal hemianopsia, and
enlargement of the pituitary gland on brain imaging, what would
you be thinking? - CORRECT ANSWER-Prolactinoma, the
most common pituitary adenoma.
What embryological layer is the anterior pituitary derived from?
- CORRECT ANSWER-Surface ectoderm
What is the most common congenital abnormality associated
with the use of Sodium Valproate during pregnancy? -
CORRECT ANSWER-neural tube defects, e.g., meningocele
because valproate inhibits intestinal folic acid absorption
resulting in teratogenicity
What is the characteristic histology of a craniopharyngioma? -
CORRECT ANSWER-On light microscopy, cysts are lined by
stratified squamous epithelium, possibly with Keratin perals.
Cysts are usually filled iwth a yellow, viscous fluid that's rich in
cholesterol crystals.
Where do craniopharyngyomas arise from? - CORRECT
ANSWER-Craniopharyngiomas are calcified cystic tumors that
arise from remnants of Rathke's pouch (embryonic precuros of
the anterior pituitary)
Failure of what process leads due neural tube defects? What
can be seen in the amniotic fluid due to leakage of fetal
cebebrospinal fluid? - CORRECT ANSWER-Failure of fusion of
the neuropores.
Alpha-fetoprotein and Acetylcholinesterase may appear in the
amniotic fluid
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