usmle 1

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tient has a tiny (0.2 cm), but exquisitely painful tumor under the nail of her index finger. Prior to surgery to remove it, local anesthetic blo

hich of the following nerves would be most likely to achieve adequate anesthesia?

a) Axillary nerve

b) Median nervec) Musculocutaneous nerve

d) Radial nerve

e) Ulnar nerve

Your answer is B

The correct answer is B

Explanation

he tumor in question is probably a glomus tumor, which is a benign tumor notorious for producing pain far out of proportion to its small sttle tricky (but important clinically for obvious reasons) because it turns out that the most distal aspect of the dorsal skin of the fingers, inc

nnervated by the palmar digital nerves rather than the dorsal digital nerves. Specifically, the median nerve through its palmar digital nerves

f the thumb, index finger, middle finger, and half of the ring finger. The axillary nerve (choice A), musculocutaneous nerve (choice C), an

D) do not supply the nail beds. The radial nerve does supply the more proximal skin of the back of the index finger. The ulnar nerve (choice

eds of the small and half of the ring finger.

Combination. 6923 Question number2

Click here to read comments or post comments about this question

An 18-year-old college student presents to the student health center complaining of a sore throat and fever. He describes

past few days and reports a loss of appetite. On examination, he has pharyngitis with cervical lymphadenopathy. Blood te

lymphocytosis and the presence of heterophil antibodies. Which of the following best describes the virus responsible for

a) Double-stranded, enveloped DNA virus

b) Double-stranded, nonenveloped DNA virus

c) Single-stranded, enveloped RNA virus

d) Single-stranded, nonenveloped DNA virus

e) Single-stranded, nonenveloped RNA virus

Your answer is E

The correct answer is A

Explanation

In this case, the patient has all the hallmarks of mononucleosis (the heterophil antibodies should have confirmed your sus

history and physical). Mononucleosis is caused by the Epstein-Barr virus, which, in turn, belongs to the herpesvirus famil

are enveloped viruses with double-stranded DNA. Remember that in addition to Epstein-Barr virus, the herpesvirus famil

simplex (1 and 2), varicella-zoster (chickenpox, shingles), and cytomegalovirus (infection in immunocompromised). Cyto
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causes infectious mononucleosis, but in these patients the heterophil test is negative. There are two families of viruses tha

with double-stranded DNA (choice B): papovaviruses and adenoviruses. There are many families of viruses that are enve

stranded RNA (choice C): arenaviruses, bunyaviruses, coronaviruses, filoviruses, flaviviruses, paramyxoviruses, orthomy

retroviruses, rhabdoviruses, and togaviruses. Parvoviruses are the only family of DNA virus with single-stranded DNA. T

envelope (choice D). There are two families of RNA virus that are single-stranded without an envelope (choice E): caliciv

picornaviruses.



A 45-year-old woman presents to her physician because of a severe "sore throat." Physical examination demonstrates fev

tender, enlarged thyroid gland, but no throat erythema. Serum thyroid studies demonstrate a mild degree of hyperthyroidi

the patient is asymptomatic, and thyroid function tests have returned to normal. She never again experiences difficulty wi

function. Which of the following was the most likely cause of her hyperthyroidism?

a) Diffuse nontoxic goiter

b) Graves disease

c) Hashimotos thyroiditis

d) Subacute granulomatous thyroiditis

e) Subacute lymphocytic thyroiditis

You have not attempted this question.

The correct answer is D

ExplanationThis patient most likely has subacute granulomatous (de Quervain's) thyroiditis, which frequently develops after a viral in

Microscopically, it is characterized by microabscess formation within the thyroid, eventually progressing to granulomatou

multinucleated giant cells. Clinically, patients may experience fever, sudden painful enlargement of the thyroid, and/or sy

hyperthyroidism. The disease usually abates within 6 to 8 weeks. Diffuse nontoxic goiter (choice A) by definition does no

hyperthyroidism. The hyperthyroidism of Graves disease (choice B) does not spontaneously remit. Hashimoto's thyroidit

transient hyperthyroidism, but then goes on to cause hypothyroidism. Subacute lymphocytic thyroiditis (choice E) can ca

hyperthyroidism, but is characteristically painless.



A carpenter gets a splinter of wood embedded in his finger pulp. What is the first line of defense against this foreign body

a) Macrophages

b) Neutrophils

c) B-lymphocytes

d) T-Lymphocytes

e) Monocytes
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ExplanationNeutrophils, which are also known as polymorphonuclear leukocytes (PMN), represent 50 to 60% of the total circulating

constitute the ''first line of defence'' against infectious agents or ''nonself'' substances that penetrate the body's physical ba

inflammatory response is initiated, neutrophils are the first cells to be recruited to sites of infection or injury.



Careful testing of the visual fields in a patient complaining of difficulty reading demonstrates a central scotoma involving

defect is most likely due to a lesion involving which of the following structures?

a) Macula

b) Optic chiasm

c) Optic radiations in the parietal lobe

d) Optic radiations in the temporal lobe

e) Optic tract



Explanation

The probable location of lesions producing visual defects is a favorite USMLE topic (and is also well worth knowing if y

work up such a patient). Here is a list that may help you sort through these problems: Central scotoma ~ macula Ipsilatera

nerve Bitemporal hemianopia ~ optic chiasm (choice B) Homonymous hemianopia ~ optic tract (choice E) Upper homon

~ temporal optic radiations (choice D) Lower homonymous quadrantanopia ~ parietal optic radiations (choice C) Also, co

defects similar to those of the optic radiations, but may spare the macula.



A 30-year-old pregnant woman complains to her physician of feeling very tired during her pregnancy. A complete blood

reveals a hematocrit of 30%, with hypersegmented neutrophils and large, hypochromic red cells. Deficiency of which of

be most likely to produce these findings?

a) Ascorbic acid

b) Calcium

c) Copper

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d) Folate

e) Iron



Explanation

The patient has a megaloblastic anemia, which can be due to deficiency of folate or B12. Pregnancy increases the need fo

nutrients used by both baby and mother, and may "unmask" a borderline dietary deficiency. For this reason, most obstetri

vitamin supplements for pregnant women. Ascorbic acid (choice A) is vitamin C, and its deficiency predisposes for capil

lesions. Calcium deficiency (choice B) predisposes for osteoporosis/osteopenia. Copper deficiency (choice C) is rare; wh

cause a hypochromic anemia, neutropenia, osteoporosis, or hypotonia. Iron deficiency (choice E) causes a microcytic, hy

with reduced mental and physical performance.



18A patient arrives in the emergency room after having suffered severe head trauma in a motorcycle accident. Radiograp

reveal a basilar skull fracture in the region of the foramen ovale. Which of the following functional losses would most lik

injury?

a) Loss of abduction of the eye

b) Loss of sensation over the forehead

c) Loss of sensation over the zygoma

d) Loss of taste sensation on the anterior 2/3 of the tongue

e) Paralysis of muscles of mastication


The correct answer is E

ExplanationThe mandibular nerve passes through the foramen ovale and may be injured by this fracture. The mandibular nerve is res

innervation of all of the muscles of mastication: the masseter, the temporalis, the medial pterygoid, and the lateral pterygo

Abduction of the eye (choice A) is produced by the lateral rectus muscle, which is innervated by the abducens nerve. The

leaves the cranial cavity and enters the orbit by passing through the superior orbital fissure. Sensation in the skin over the

is provided by the ophthalmic division of the trigeminal nerve. The ophthalmic division leaves the cranial cavity and ente

through the superior orbital fissure. Sensation in the skin over the zygoma (choice C) is provided by the maxillary divisio

nerve. The maxillary division leaves the cranial cavity and enters the pterygopalatine fossa by passing through the forame

sensation on the anterior 2/3 of the tongue (choice D) is provided by the chordae tympani, a branch of the facial nerve. Th

the cranial cavity and enters the temporal bone by passing into the internal auditory meatus. The chordae tympani leave th

enter the infratemporal fossa by passing through the petrotympanic fissure.

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Which of the following organisms is the most common cause of community-acquired pneumonia?

a) Chlamydia pneumoniae

b) Haemophilus influenzae

c) Mycoplasma pneumoniae

d) Staphylococcus aureus

e) Streptococcus pneumoniae



Explanation

The correct answer is E. The most common bacteria implicated in community-acquired pneumonia is the pneumococcus,

pneumoniae. Other organisms frequently implicated in patients less than age 60 without comorbidity include Mycoplasm

respiratory viruses, Chlamydia pneumoniae, and Haemophilus influenzae. When community-acquired pneumonia occurs

patients with comorbidity, aerobic gram-negative bacilli and Staphylococcus aureus are added to the list. The organisms

and C are important causes of community-acquired pneumonia, but are not the most frequent causes. Staphylococcus aur

important cause of community-acquired pneumonia (particularly in the elderly and in patients with comorbidity), but is n

cause



A 25-year-old woman with sickle cell anemia complains of steady pain in her right upper quadrant with radiation to the ri

especially after large or fatty meals. Her physician diagnoses gallstones. Of which of the following compounds are these

composed?

a) Calcium bilirubinate

b) Calcium oxalate

c) Cholesterol

d) Cholesterol and calcium bilirubinate

e) Cystine



Explanation

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Bilirubin is a degradative product of hemoglobin metabolism. Bilirubin (pigment) stones are specifically associated with

production in hemolytic anemias, including sickle cell anemia. Bilirubin stones can also be seen in hepatic cirrhosis and l

Calcium oxalate stones (choice B) and cystine stones (choice E) are found in the kidney, rather than the gallbladder. Pure

(choice C) are less common than mixed gallstones, but have the same risk factors, including obesity and multiple pregnan

(choice D) are the common "garden variety" gallstones, found especially in obese, middle aged patients, with a female pr



Damage to which of the following structures might produce hair cell loss?

a) Basilar membrane

b) Organ of Corti

c) Reissners membrane

d) Scala tympani

e) Scala vestibuli



Explanation

The correct answer is B. The structure of the cochlea is complex. The organ of Corti contains hair cells from the cochlear

vestibulocochlear nerve (CN VIII). These cells rest on the basilar membrane (choice A), which separates the scala tympan

scala media. The hairs of the hair cells are embedded in the tectorial membrane, and movement of the basilar membrane b

to bend the hairs, which generates action potentials by the hair cells. The tectorial membrane that lies on the hair cells doe

boundary between the different scala; the membrane separating the scala media from the scala vestibuli (choice E) is Reis

membrane (choice C).



A certain type of cell plays a central role in inflammatory and immediate allergic reactions and settles in connective tissu

not circulate in the blood stream. This type of cell is known as a

a) Basophil

b) Mast cell

c) Eosinophil

d) Neutrophil

e) Macrophage


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Explanation

Mast cells and basophils play a central role in inflammatory and immediate allergic reactions. They are able to release po

mediators, such as histamine, proteases, chemotactic factors, cytokines and metabolites of arachidonic acid that act on themuscle, connective tissue, mucous glands and inflammatory cells.
Mast cells settle in connective tissues and usually

blood stream.
Basophils are the smallest circulating granulocytes with relatively the least known function. They aris

and following maturation and differentiation, are released into the blood circulation. If they are adequately stimulated the

tissues.



A patient has a painful ulcer on the tip of his tongue. Which of the following cranial nerves carries the pain sensation he e

a) V2

b) V3

c) VII

d) IX

e) X



Explanation

The innervation of the tongue is complex. The mandibular division of the trigeminal nerve (V3) carries general somatic s

anterior two-thirds of the tongue. The maxillary division (V2, choice A) carries somatic sensation from the palate, upper g

The facial nerve (VII, choice C) carries taste from the anterior two-thirds of the tongue. The glossopharyngeal nerve (IX,

sensation and taste from the posterior one-third of the tongue. The vagus nerve (X, choice E) carries sensation from the lo



A 60-year-old male with angina comes to the emergency room with severe chest pain unresponsive to sublingual nitrogly

ST segment elevation in the anterolateral leads, and thrombolytic therapy is initiated. If streptokinase is given to this patie

thrombolysis after binding to which of the following proteins?

a) Antithrombin III

b) Fibrin

c) Plasminogen

d) Protein C

e) Thrombomodulin

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The correct answer is C

Explanationhe fibrinolytic activity of streptokinase is due to its ability to bind and cleave plasminogen, producing plasmin. Plasmin d

both between and within the fibrin polymers, thus breaking up thrombi and potentially restoring blood flow to ischemic c

same mechanism of fibrinolysis is shared by urokinase and tissue-plasminogen activator (tPA). Antithrombin III (choice

inhibitor that binds to and inactivates thrombin. Antithrombin III is anticoagulant, not fibrinolytic



Which receptor is innervated by nerves that combine with the vagus nerve ?

a) Carotid sinus receptors

b) Aortic arch receptors

c) Central chemoreceptors

d) pulmonary artery receptors

e) Atrial receptors



Explanation

The aortic arch baroreceptors are innervated by the aortic nerve, which then combines with the vagus nerve (X cranial ne

brainstem; bilateral vagotomy, therefore, denervates the aortic arch baroreceptors.

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Explanation

Collagen formation begins with transcription of mRNA from appropriate DNA genes in the nucleus. While still within th

is spliced. It is then transported through the cytoplasm to the ribosomes on the rough endoplasmic reticulum. Individual cthe ribosomes, with the ends feeding into the endoplasmic reticulum lumen. Within the lumen, glycosylation of the indiv

The material then moves toward the Golgi bodies (whose lumens are connected to the endoplasmic reticulum) where the

procollagen form. The procollagen is then secreted into the extracellular space, where cleavage of pro-peptides and cross

triple helices occurs, maturing the collagen. The extracellular space (choice A) is the site of procollagen cleavage and cro

nucleus (choice C) is the site of mRNA transcription and splicing. The rough endoplasmic reticulum (choice D) is the site

and glycosylation. The smooth endoplasmic reticulum (choice E) does not participate in collagen synthesis



A 6-month-old boy is brought to the pediatrician by his parents, who are first cousins. This is their first child. Physical ex

small, thin, lethargic infant with slightly misshapen long bones. His features are somewhat coarse. Joint movements are r

are clouded, and his gums are underdeveloped. His liver is not enlarged. Serum levels of acid hydrolases are found to be

most likely has a defect in which of the following metabolic activities?

a) Degradation of dermatan sulfate and heparan sulfate

b) Degradation of gangliosides

c) Degradation of glycogen

d) Degradation of sphingomyelin

e) Phosphorylation of mannose moieties



ExplanationThe patient has I-cell disease, also known as mucolipidosis II, which is due to a defective UDP-N-acetylglucosamine-1-p

enzyme that phosphorylates mannose on enzymes destined for lysosomes. Proteins coded by nuclear DNA are synthesize

ribosomes, which may be either "free" or associated with the endoplasmic reticulum to form the rough endoplastic reticul

synthesized on the RER are transferred into the Golgi apparatus, where they undergo further modifications that determine

part of the Golgi apparatus, become part of the plasma membrane, or are shipped to lysosomes or mitochondria. Proteins

transport to a specific intracellular site follow the default pathway and are exported into the extracellular compartment. Th

of the acid hydrolases (and probably other enzymes) to the lysosomes is phosphorylation of a terminal mannose moiety o

oligosaccharide to form mannose 6-phosphate. In I-cell disease, this terminal mannose moiety is not phosphorylated, andfollow the default pathway and are secreted. Deficiency of alpha-L-iduronidase results in lysosomal accumulation of derm

heparan sulfate (choice A) in several conditions such as mucopolysaccharidosis I, Hurler's disease, or Hurler's/Scheie dis

A deficiency (Tay-Sachs disease) is one example of a condition in which ganglioside accumulation occurs (choice B). Th

diseases in which glycogen degradation (choice C) is defective. These are collectively termed glycogen storage diseases s

abnormal cellular accumulation of glycogen. In Pompe's disease, or type II glycogen storage disease, a lysosomal glucosi

resulting in lysosomal glycogen accumulation. Deficiency of sphingomyelinase (choice D), an enzyme involved in degra

sphingomyelin, results in Niemann-Pick disease. Phosphorylation of tyrosine moieties (choice F) is unrelated to lysosome

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enzymes; however, decreased ability to phosphorylate tyrosine moieties might be associated with diabetes or dwarfism. .



A child has a history of recurrent infections with organisms having polysaccharide antigens (i.e., Streptococcus pneumon

influenzae). This susceptibility can be explained by a deficiency of

a) C3 nephritic factor

b) C5

c) IgG subclass 2

d) myeloperoxidase in phagocytic cells

e) secretory IgA


The correct answer is C

Explanation

IgG is the predominant antibody in the secondary immune response. IgG subclass 2 is directed against polysaccharide an

in the host defense against encapsulated bacteria. C3 nephritic factor (choice A) is an IgG autoantibody that binds to C3 c

resistant to inactivation. This leads to persistently low serum complement levels and is associated with Type II membrano

glomerulonephritis. C5 (choice B) is a component of the complement system. C5a is an anaphylatoxin that effects vasodi

inflammation. It is also chemotactic for neutrophils and monocytes and increases the expression of adhesion molecules. A

would affect the acute inflammatory response against any microorganism or foreign substance. Myeloperoxidase in phag

is an element of the oxygen-dependent pathway present in phagocytic cells that effectively kills bacterial cells. The hydro

complex is considered the most efficient bactericidal system in neutrophils. Chronic granulomatous disease is associated

NADPH oxidase, which converts molecular oxygen to superoxide (the first step in the myeloperoxidase system). Patients

granulomatous infections and staphylococcal infections. Secretory IgA (choice E) is the immunoglobulin associated with

Selective IgA deficiency is the most common hereditary immunodeficiency. In this disorder, there is failure of the B cell

chain class from IgM to IgA. Patients have an increased incidence of sinopulmonary infections, diarrhea, allergies, and au



Which of the following is true of the optic disc?

a) no arteries pass through it

b) no veins pass through it

c) it appears dark red on fundoscopy

d) contains a concentration of photoreceptors

e) it is normally less than 1cm in diameter

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ExplanationThis is the point at which axons leave the eyeball and join the optic nerve. Also, arteries enter and veins leave the retina a

are no photoreceptors here, hence it is known as the 'blind spot'. It is a pinky-yellow oval, approximately 2mm in diamete

nasal retina



what suspensory ligaments connect the outer edge of the lens of the eye with the ciliary processes?

a) zonnules of Zinn

b) zonnules of Schlemm

c) cruciate ligaments

d) ligaments of Treitz

e) ciliary ligaments



Explanation

Also known as the suspensory ligament, the Zonnules of Zinn comprise a network of collagen fibres which connect the o

with the ciliary processes. In this hammock of fine fibres lies the lens. To the right is the margin of the vitreous humour, t

posterior chamber, which lies between the zonnules and the iris. Below in the ciliary processes lie cells which are excreti

which flows to the pupil.

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d) Depth of lesion

e) Sharpness of border between lesion and adjacent skin



Explanation

The lesion is a malignant melanoma. Melanomas can develop either de novo or in an existing mole. Sunlight exposure is

factor and fair-skinned persons are at increased risk of developing melanoma. The most significant factor for long term p

of the lesion, since the superficial dermis lies about 1 mm under the skin surface, and penetration to this depth is associate

incidence of metastasis than is seen with a more superficial location. The circumference of the lesion (choice A) is much

depth, since one form of melanoma (superficial spreading) can still have good prognosis despite large size, if it has not ex

the superficial dermal lymphatic bed. The darkness (choice B) or degree of variation in color (choice C) do not have prog

once melanoma is diagnosed. Irregularity, or fuzziness at the border (choice E) of a mole-like lesion is a good clue to pot

does not affect prognosis once a melanoma is diagnosed.

A 10-year-old male presents to the pediatrician because of problems

while eating. He can chew food but has problems swallowing the chewed

pieces, and feels them in his throat. A radiographic study is performed

that shows normal musculature but abnormal esophageal peristalsis. Nomasses are seen. Which of the following nerves should be tested for

abnormalities?

A. Hypoglossal and phrenic

B. Hypoglossal and splanchnic

C. Glossopharyngeal and vagus

D. Phrenic and vagus

E. Splanchnic and vagus

Answer

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2A 40-year-old man with adult polycystic kidney disease is brought to

the emergency room in a coma. CT scan of the head demonstrates asubarachnoid hemorrhage without parenchymal hemorrhage. Which of

the following is the most likely source of the bleeding?

A. AV malformation

B. Bridging veins

C. Charcot-Bouchard aneurysm

D. Circle of Willis

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E. Middle meningeal artery

Answer

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3An unconscious patient with sepsis in the intensive care unitundergoes a 2-hour period of severe hypotension. Blood chemistries

taken during the following 48 hours show rising creatine kinase MB

fraction (CK-MB), peaking at 5 times the upper limit of normal. ECG

findings are equivocal, with some degree of flat S-T segment

depression over several leads. Which of the following is the

most likely diagnosis?

A. Prinzmetal angina

B. Stable angina

C. Subendocardial infarction

D. Transmural infarction

E. Unstable anginaAnswer

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4A 65 year-old man is admitted to the coronary care unit with a

diagnosis of a large myocardial infarct (MI) of the left ventricle.

On his 6th postinfarct day, he goes into shock and dies, manifesting

signs and symptoms of cardiac tamponade. Which of the following

complications is the most likely cause of this patient's death?

A. Aortic dissection

B. Extension of previous MI

C. Fatal arrhythmiaD. Rupture of the left ventricular wall

E. Rupture of papillary muscle

Answer

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5A newborn appears normal at birth, but develops vomiting and diarrhea

accompanied by jaundice and hepatomegaly within the first few weeks of

life. Within months, the baby has obvious cataracts and ascites. The

infant is switched to a milk-free diet, which stabilizes but does not

completely reverse his condition. By one year of age, he has developed

mental retardation. Which of the following is the most likely diagnosis?A. Cystic fibrosis

B. Galactosemia

C. McArdle's disease

D. Von Gierke's disease

E. Wilson's disease

Answer

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--------------------------------------------------------------------------------

6A 25-year-old man presents with headache, dizziness, and claudication.

Blood pressure measurements reveal hypertension in the upper limbs and

hypotension in the lower limbs. Which of the following additionalfindings would be most likely in this case?

A. Aortic valvular stenosis

B. Notching of inferior margins of ribs

C. Patent ductus arteriosus

D. Pulmonary valvular stenosis

E. Vasculitis involving the aortic arch

Answer

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7A patient has a tiny (0.2 cm), but exquisitely painful tumor under

the nail of her index finger. Prior to surgery to remove it, localanesthetic block to a branch of which of the following nerves would

be most likely to achieve adequate anesthesia?

A. Axillary nerve

B. Median nerve

C. Musculocutaneous nerve

D. Radial nerve

E. Ulnar nerve

Answer

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8Tissue from a spontaneous abortion is submitted to the laboratory,where an astute pathologist notes the presence of mature fetal tissue

that contains Barr bodies. The fetus may have had which of the following

genotypes?

A. Classic Turner syndrome (45, X)

B. Edward's syndrome (47, XY+1Cool

C. Klinefelter's syndrome (47, XXY)

D. Normal male (46, XY)

E. XYY syndrome (47, XYY)

Answer

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9A 78-year-old woman is brought to the emergency department because of

slowly developing confusion over the past ten days. Careful physical

examination demonstrates a relatively small laceration of the scalp.

CT of the head would be most likely to reveal which of the following?

A. Epidural hematoma

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B. Mixed parenchymal and subarachnoid hemorrhage

C. Multiple tiny hemorrhages of the putamen

D. Subarachnoid hemorrhage

E. Subdural hematoma

Answer--------------------------------------------------------------------------------

10A 22-year-old woman presents to her physician with amenorrhea,

weight loss, anxiety, tremor, heat intolerance and palpitations.

Laboratory examination is consistent with hyperthyroidism, and

the physician prescribes propylthiouracil. The patient's response

to propylthiouracil is disappointing, and the symptoms recur,

then worsen. Subtotal thyroidectomy is successfully performed,

but following the surgery, the woman is extremely hoarse, and can

barely speak above a whisper. This hoarseness is most probably

related to damage to a branch which of the following cranial nerves?A. Facial

B. Glossopharyngeal

C. Hypoglossal

D. Trigeminal

E. Vagus

Answer

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11A 24-year-old female is brought to the emergency room after

threatening to kill herself by cutting her wrists. She has multiple

scars on her wrists, which she admits were caused by prior suicideattempts. She states she is very angry at her boyfriend, who left her

for another woman. She previously thought her boyfriend was an angel

and now she thinks he is a monster. She feels very empty inside.

While smiling, she states that she is depressed. During the interview,

she drops to the ground, but continues to talk while lying on the floor

. She believes nobody understands her. What is her underlying personality

disorder?

A. Antisocial

B. Borderline

C. Histrionic

D. NarcissisticE. Schizoid

Answer

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12A high school basketball player passes out in the middle of a game. He

is rushed to the emergency room, where he regains consciousness. He

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claims that just before he fainted, he had difficulty breathing and

experienced palpitations. On physical exam, he has a bifid apical

impulse and a coarse systolic murmur at the left sternal border.

The echocardiogram reveals ventricular hypertrophy with asymmetric

septal thickening. Which of the following would increase the intensityof his heart murmur?

A. Elevating his legs

B. Increasing sympathetic tone

C. Performing the Valsalva maneuver

D. Squatting

Answer

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13A 63-year-old man complains of trouble swallowing and hoarseness. On

physical exam, he is noted to have ptosis and a constricted pupil on

the left, and a diminished gag reflex. Neurological examination showsdecreased pain and temperature sensation on the left side of his face

and on the right side of his body. Which of the following vessels is

most likely occluded?

A. Anterior inferior cerebellar artery (AICA)

B. Anterior spinal artery

C. Middle cerebral artery (MCA)

D. Posterior cerebral artery (PCA)

E. Posterior inferior cerebellar artery (PICA)

Answer

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14Examination, at autopsy, of the brain of a man who died in an intensive

care unit demonstrates bilateral, linear, parasagittal areas of

coagulative necrosis in the junctional zone between the anterior

and medial cerebral arterial systems. Which of the following is

the most likely etiology?

A. Bacterial infection

B. Fungal infection

C. Ischemia

D. Tumor

E. Viral infection

Answer--------------------------------------------------------------------------------

15A 55-year-old woman presents to her physician after several episodes

of syncope. Physical examination is remarkable for a

low-pitched "plopping" sound during mid-systole.

Two-dimensional echocardiography demonstrates a

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ball-valve type obstruction of the mitral valve.

Which of the following would most likely be observed

if the cause of the obstruction were biopsied?

A. Benign glandular tissue

B. Densely packed smooth muscleC. Densely packed striated muscle

D. Malignant glandular tissue

E. Scattered mesenchymal cells in a myxoid background

Answer

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16The presence of which of the following features in an atherosclerotic

plaque indicates that it has become a complicated lesion?

A. Cholesterol crystals

B. Chronic inflammatory cells

C. Intimal smooth muscleD. Lines of Zahn

E. Necrotic cell debris

Answer

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17A 46-year-old woman presents to her physician with "double vision"

and is unable to adduct her right eye on attempted left lateral gaze.

Convergence is intact. Both direct and consensual light reflexes are

normal. Which of the following structures is most likely to be affected?

A. Left oculomotor nerve

B. Medial longitudinal fasciculusC. Right abducens nerve

D. Right oculomotor nerve

E. Right trochlear nerve

Answer

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18A patient arrives in the emergency room after having suffered severe

head trauma in a motorcycle accident. Radiographic studies of the head

reveal a basilar skull fracture in the region of the foramen ovale.

Which of the following functional losses would most likely be related

to this injury?A. Loss of abduction of the eye

B. Loss of sensation over the forehead

C. Loss of sensation over the zygoma

D. Loss of taste sensation on the anterior 2/3 of the tongue

E. Paralysis of muscles of mastication

Answer

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--------------------------------------------------------------------------------

19A 64-year-old man has a myocardial infarction, and is hospitalized. He

is seen by a cardiologist, who orders echocardiographic studies, which

demonstrate a portion of the apex of the left ventricle that bulgesoutward during systole and inward during diastole. This finding is

most likely related to disease involving which of the following structures?

A. Aortic valve

B. Circumflex artery

C. Left anterior descending artery

D. Mitral valve

E. Tricuspid valve

Answer

--------------------------------------------------------------------------------

20A mailman gets a severe bite wound from a pit bull guarding ajunkyard. The wound is cleansed and he receives a booster injection

of tetanus toxoid and an injection of penicillin G. Several days later,

the wound is inflamed and purulent. The exudate is cultured on blood

agar and yields gram-negative rods. Antibiotic sensitivity tests are

pending. The most likely agent to be isolated is

A. Bartonella henselae

B. Brucella canis

C. Clostridium tetani

D. Pasteurella multocida

E. Toxocara canis

Answer--------------------------------------------------------------------------------

21A 7-year-old boy is referred to a specialty clinic because of

digestive problems. He often experiences severe abdominal cramps

after eating a high fat meal. He is worked up and diagnosed with

a genetic defect resulting in a deficiency of lipoprotein lipase.

Which of the following substances would most likely be elevated

in this patient's plasma following a fatty meal?

A. Albumin-bound free fatty acids

B. Chylomicrons

C. HDLD. LDL

E. Unesterified fatty acids

Answer

--------------------------------------------------------------------------------

22A 10-year-old girl who is a suspected victim of child abuse is

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referred to a psychologist for evaluation. As part of her workup,

the patient is asked to construct a story based on pictures. Which

of the following psychometric measures was utilized?

A. Minnesota Multiphasic Personality Inventory

B. Myers-Briggs Personality InventoryC. Rorschach Test

D. Thematic Apperception Test

E. Type A and B Behavior Patterns Test

Answer

--------------------------------------------------------------------------------

23Which of the following enzymes is located at arrow 1 in the electron

micrograph above?

A. Carnitine acyltransferase II

B. Fatty acyl CoA synthetase

C. Glucose-6-phosphate dehydrogenaseD. Hexokinase

E. Pyruvate kinase

Answer

--------------------------------------------------------------------------------

24A 22-year-old female college student is brought into the emergency

room by the police, who found her walking back and forth across a busy

street, talking to herself. The young woman appears to be oriented

with respect to person, place, and time. Her first hospital admission

was two months ago for a similar condition. During a psychiatricinterview, she has difficulty concentrating, and seems to hear voices

. A phone call to her sister provides the additional information that

the girl dropped out of school three months ago and has been living on the street. Urine toxicol

This patient is most likely exhibiting the signs and symptoms of

A. schizoaffective disorder

B. schizoid personality disorder

C. schizophrenia

D. schizophreniform disorder

E. schizotypal personality disorder

Answer

--------------------------------------------------------------------------------

25A 42-year-old man has just been informed that he has poorly

differentiated small cell carcinoma of the lung. When asked if

he understands the serious nature of his illness, the patient

proceeds to tell his physician how excited he is about renovating

his home. This patient is exhibiting

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A. denial

B. displacement

C. projection

D. rationalization

E. reaction formationF. sublimation

Answer

--------------------------------------------------------------------------------

26An increase in which of the following best explains the mechanism by

which the cardiac output increases in severe anemia?

A. Arteriolar diameter

B. Blood viscosity

C. Peripheral vascular resistance

D. Splanchnic blood flow

E. Tissue oxygen tensionAnswer

--------------------------------------------------------------------------------

27A 2-year-old retarded child is evaluated by a metabolic specialist.

The child's history is significant for failure to thrive and progressive

neurologic deterioration, including deafness and blindness. Physical

examination is remarkable for hepatosplenomegaly, as well as a

cherry-red spot on funduscopic examination. These symptoms are

consistent with a diagnosis of

A. Hunter syndrome

B. Niemann-Pick diseaseC. Pompe's disease

D. tyrosinosis

E. von Gierke's disease

Answer

--------------------------------------------------------------------------------

28An 8-month-old female child is brought to medical attention because

her first four teeth show several discrete, discolored, circumferential

bands that show very little enamel. Excessive levels of which of the

following may have produced this defect?

A. BilirubinB. Fluoride

C. Parathormone

D. Thyroid hormone

E. Vitamin C

Answer

--------------------------------------------------------------------------------

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29Which of the following complications is currently the major

limitation to the long-term success of cardiac transplantation?

A. Allograft rejection

B. Graft arteriosclerosisC. Graft atherosclerosis

D. Opportunistic infections

E. Lymphoma

Answer

--------------------------------------------------------------------------------

30A child develops a tumor of the cerebellum. Biopsy reveals evidence

of both neuronal and glial differentiation. Which of the following is

the most likely diagnosis?

A. Astrocytoma

B. Glioblastoma multiformeC. Medulloblastoma

D. Meningioma

E. Oligodendroglioma

Answer

--------------------------------------------------------------------------------

31A 56-year-old man visits his physician with complaints of complete

exhaustion after mowing the lawn in his small front yard. He also

complains of dizziness, irritability, difficulty sleeping, and loss

of libido. On physical examination, the man's skin, conjunctiva, and

oral mucosa are pale. A blood test indicates the man's hemoglobin is7 g/dL. Which of the following findings is also likely to be present

in this man?

A. Bradycardia

B. Cyanosis

C. Low stroke volume

D. Warm hands

E. Wide pulse pressure

Answer

--------------------------------------------------------------------------------

32A 55-year-old man had been in good health since receiving a hearttransplant for severe atherosclerotic disease. Five years after

transplantation, the patient died suddenly, without any premonitory

symptoms, while working in his garden. He had been maintained on

cyclosporin since his transplant. Which of the following complications

would most likely be found at autopsy in the transplanted heart?

A. Allograft rejection

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B. Atherosclerosis of coronary arteries

C. Graft vascular disease

D. Hyaline arteriolosclerosis

E. Hyperplastic arteriolosclerosis

Answer--------------------------------------------------------------------------------

33An elderly lady is brought to the emergency room after drinking

insecticide that she thought was tea. After her stomach is pumped

, her sense of smell is tested and it is found that she can not

distinguish common smells (e.g., an orange, coffee). CT scan of

the head demonstrates a mass in the olfactory groove area. The

axons likely compressed by this mass project to which of the

following structures?

A. Insula

B. Nucleus ambiguusC. Post-central gyrus

D. Pre-central gyrus

E. Pyriform cortex

Answer

--------------------------------------------------------------------------------

34A 27-year-old man develops bilateral parotid gland swelling and

orchitis, and is generally ill with fever of 102 F. Which of the

following substances is most likely to be significantly elevated

in the patient's serum?

A. Alanine aminotransferase (ALT)B. Amylase

C. Aspartate aminotransferase (AST)

D. Ceruloplasmin

E. Creatine phosphokinase, MB isoenzyme (CPK-MB)

Answer

--------------------------------------------------------------------------------

35A 55-year-old man presents to the emergency room with crushing

substernal pain and left shoulder pain of 2 hours duration. The

pain is not relieved by sublingual nitroglycerin, and theelectrocardiogram shows ST elevation in several leads. Aspirin

and streptokinase therapy are initiated, and the patient is

admitted to the intensive care unit. The next morning, serum

cardiac enzymes are elevated to 4 times the upper limit of

normal, and the electrocardiographic changes are still

present. Which of the following is the most likely diagnosis?

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A. Prinzmetal's angina

B. Stable angina

C. Subendocardial infarction

D. Transmural infarction

E. Unstable anginaAnswer

--------------------------------------------------------------------------------

36Which of the following amino acids is post-translationally

hydroxylated in the cytoplasm of fibroblasts?

A. Cysteine

B. Glycine

C. Proline

D. Serine

E. Tyrosine

Answer--------------------------------------------------------------------------------

37Microscopic examination of a cancer cell reveals a cell in an

abnormal telophase in which three clusters of chromosomes are

seen. An abnormality of which of the following would be most

likely to produce this alteration?

A. Chiasma

B. Mitotic spindle

C. Mosaicism

D. Polar body

E. SynapsisAnswer

--------------------------------------------------------------------------------

38A 58-year-old man with fainting spells and exercise intolerance

is found to have a bicuspid aortic valve with marked aortic stenosis.

Which of the following physical findings would be prominent in this

patient?

A. Diastolic murmur

B. Heave at left parasternal border

C. Loud S2 heart sound

D. Loud S3 heart soundE. Weak peripheral pulse

Answer

--------------------------------------------------------------------------------

39A 57-year-old female is found unconscious on her kitchen floor

after having suffered a myocardial infarction. She has pulmonary

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edema and distended jugular and peripheral veins. A midsystolic

gallop is heard upon chest auscultation. EKG shows prominent Q

waves in leads II, III, and aVF. Which of the following is

most consistent with the patient's condition?

Preload Cardiac output PAWP CVP Vascular resistance Mixed venous oxygenA. Increased Decreased Decreased Increased Increased Decreased

B. Increased Increased Decreased Decreased Decreased Increased

C. Increased Decreased Increased Increased Increased Decreased

D. Increased Increased Increased Increased Decreased Decreased

E. Decreased Decreased Increased Decreased Increased Decreased

F. Decreased Increased Decreased Increased Decreased Increased

G. Decreased Decreased Increased Decreased Decreased Decreased

Answer

--------------------------------------------------------------------------------

40A 48-year-old man complaining of chest pain is brought to the emergency

room. Physical examination followed by echocardiography demonstrates

aortic stenosis. His coronary blood flow is increased. Which of the

following is the most likely explanation for the increased coronary

blood flow in this individual?

A. Decreased left ventricular oxygen consumption

B. Decreased left ventricular pressure

C. Decreased left ventricular work

D. Increased cardiac tissue adenosine concentration

E. Increased cardiac tissue oxygen concentration

Answer--------------------------------------------------------------------------------

41A 45-year-old man presents to the emergency department with severe

headache and vomiting. A CT scan shows a well-circumscribed cystic

lesion within the 3rd ventricle; there is no calcium deposition.

The cyst is surgically removed. On histologic examination, the wall

of the cyst consists of a single layer of mucin-producing columnar

epithelium with a ciliated apical surface. Which of the following is

the most likely diagnosis?

A. Colloid cyst

B. CraniopharyngiomaC. Cysticercosis

D. Echinococcus cyst

E. Pilocytic astrocytoma

Answer

--------------------------------------------------------------------------------

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42A 36-year-old female is brought to the emergency room by her husband

who says that she "complained of a severe headache then lost consciousness." She has a history

and had been on several different medications. The examining physician notes that she is unab

arms and legs, but can blink her eyes. When the physician asks her to blink twice if she can hea

promptly does so. In which of the following structures is this woman's lesion most likely locateA. Cervical spinal cord

B. Medulla oblongata

C. Midbrain

D. Pons

E. Thalamus

Answer

--------------------------------------------------------------------------------

43A 71-year-old man has been in excellent health, and practicing

competently as an attorney. He is brought to the emergency room

following a motor vehicle accident. A workup, including imaging ofthe spine, thorax, and head, is negative, but the patient is admitted

for overnight observation. His injuries include several lacerations to

the face and extremities as well as several contusions to the thorax.

Three weeks later, he is admitted to the hospital for confusion. A

neurologic exam is normal except that he is not oriented to time or

place, and can recall only 1 out of 6 objects after 3 minutes. Which

of the following is the most likely diagnosis?

A. Alzheimer's disease

B. Brain metastases

C. Epidural hematoma

D. Normal pressure hydrocephalusE. Subdural hematoma

Answer

--------------------------------------------------------------------------------

44A work diagram showing changes in left ventricular volume and pressure

during one cardiac cycle is shown above for a normal heart (diagram A)

and following aortic valvular disease (diagram B). Diagram B shows which

of the following compared to diagram A?

A. Decreased work for a greater stroke volume

B. Decreased work for a lower stroke volume

C. Decreased work for the same stroke volumeD. Increased work for a greater stroke volume

E. Increased work for a lower stroke volume

F. Increased work for the same stroke volume

Answer

--------------------------------------------------------------------------------

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45An 80-year-old woman dies after a long history of progressive memory loss,

apraxia, and recurrent episodes of confusion. In the last months of life

she was bedridden and unable to recognize familiar faces and objects.

The pathologist identifies numerous flame-shaped intracytoplasmic

inclusions in neurons of the neocortex and hippocampus. Theseconsist of paired helical filaments (PHFs) on electron microscopy.

Which of the following biochemical changes most likely accounts for

the development of PHFs in this condition?

A. Abnormal degradation of amyloid precursor protein (APP)

B. Abnormal phosphorylation of tau

C. Accumulation of advanced glycosylation end (AGE) products

D. Increased expression of APP

E. Precipitation of insoluble a-tubulin

Answer

--------------------------------------------------------------------------------

46The activity of which of the following enzymes is directly affected by

citrate?

A. Fructose-2,6-bisphosphatase

B. Isocitrate dehydrogenase

C. Phosphofructokinase I

D. Pyruvate carboxylase

E. 6-phosphogluconate dehydrogenase

Answer

--------------------------------------------------------------------------------

47While a physician is using a water-filled syringe to expel wax from theear canal of an elderly patient, the man suddenly faints. This event can

be explained by the fact that the posterior half of the external ear

canal receives sensory innervation from the

A. auricular branch of the vagus nerve

B. auriculotemporal nerve

C. greater auricular nerve

D. lesser occipital nerve

E. vestibulocochlear nerve

Answer

--------------------------------------------------------------------------------

48Which of the following structures is found only in Gram-negative

microorganisms?

A. Cell envelope

B. Exotoxin

C. Peptidoglycan

D. Periplasmic space

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E. Teichoic acids

Answer

--------------------------------------------------------------------------------

49A scientist wishes to study free radical production under ischemicconditions. He decides to produce cerebral ischemia by tying off an

artery of the brain. Ligation of which of the following arteries

would be most likely to produce significant ischemic damage?

A. Anterior cerebral artery at its origin from the internal carotid artery

B. Anterior communicating artery

C. Middle cerebral artery at its origin from the internal carotid artery

D. Posterior cerebral artery at its origin from the basilar artery

E. Posterior communicating artery

Answer

--------------------------------------------------------------------------------

50A 52-year-old woman has long-standing rheumatoid arthritis (RA) and

is being treated with corticosteroids and nonsteroidal anti-inflammatory

drugs (NSAIDs). Which of the following cardiac complications may arise in

this clinical setting?

A. Constrictive pericarditis

B. Dilated cardiomyopathy

C. Hypersensitivity myocarditis

D. Hypertrophic cardiomyopathy

E. Restrictive cardiomyopathy

Answer

--------------------------------------------------------------------------------

Answers

--------------------------------------------------------------------------------

1The correct answer is E. The upper 2/3 of the esophagus contains striated muscle. It is derived

pharyngeal arches and innervated by the vagus nerve (CN X). The lower 1/3 contains smooth m

splanchnic mesoderm and is innervated by the splanchnic plexus.

The hypoglossal nerve (choices A and B), or CN XII, moves the tongue.

The phrenic nerve (choices A and D), derived from C3, C4, and C5, innervates the muscle of the

The glossopharyngeal nerve (choice C), or CN IX, functions in taste, swallowing, and salivation,

monitoring the activity of the carotid body.

--------------------------------------------------------------------------------2The correct answer is D. Two relationships are useful in solving this problem. The first relatio

polycystic kidney disease has a specific association with berry aneurysms involving the circle o

branches. The second relationship is that spontaneous subarachnoid hemorrhages are most oft

bleeding from berry aneurysms. The berry aneurysms develop at sites of congenital weakness

points) of the relatively unsupported vessels of the circle of Willis.

AV malformations (choice A) tend to produce mixed parenchymal and subarachnoid hemorrha

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Rupture of bridging veins (choice B) produces a subdural hematoma.

Rupture of Charcot-Bouchard aneurysms (choice C) can be seen with hypertension (which may

polycystic kidney disease). Such rupture produces intraparenchymal hemorrhage, which if sev

to the subarachnoid space.

Rupture of the middle meningeal artery (choice E) produces epidural hematoma--------------------------------------------------------------------------------3The correct answer is C. The hig

indicates that the patient has sustained an infarction rather than angina. Subendocardial, rathe

transmural, infarction is most likely in the setting of known, prolonged severe hypotension, and

nature of the ECG findings confirms this diagnosis. Subendocardial infarction occurs in settings

poor perfusion complicated by increased demand or transient vasospasm. Subendocardial mus

especially vulnerable because it is farthest from the arterial supply.

In Prinzmetal angina (choice A) and stable angina (choice B), the CK-MB would not be expected

significantly.

Transmural infarction (choice D) is not specifically expected in the setting of shock. It produces

ECG changes that are usually localized (unless a very large infarct has occurred) to a few leads.

In unstable angina (choice E), an increase in cardiac enzymes may be seen, but is usually less thupper limit of normal.

--------------------------------------------------------------------------------4The correct answer is D. Ruptur

ventricular wall is a frequently fatal complication that may occur in the first week after myocar

(MI). At this stage, the infarcted area is composed of friable necrotic myocardium and early gra

is during this crucial phase, therefore, that rupture usually occurs. Blood rushes out, filling the p

and causing compression of the left ventricle. Cardiac tamponade ensues, and the patient usual

cardiogenic shock.

Aortic dissection (choice A) is not a complication of MI, although cardiac tamponade may also f

condition when dissection works its way back toward the aortic root. Aortic dissection usually

aortas affected by cystic medial degeneration (CMD), which is due to fragmentation of elastic la

accumulation of myxoid material in the aortic media. CMD may be either sporadic or associatedsyndrome.

Extension of a previous MI (choice B) may occur in the first few hours or days after MI. It may a

precipitate cardiogenic shock and/or arrhythmias, but it does not cause cardiac tamponade.

Arrhythmias (choice C) are frequent complications of MI and are often fatal, producing cardiac

(ventricular fibrillation) or aggravating cardiac dysfunction.

If infarction involves papillary muscles, these may rupture (choice E). This complication is follo

dysfunction and may manifest with signs of mitral regurgitation and acute congestive heart fail

--------------------------------------------------------------------------------5The correct answer is B. Galact

autosomal recessive disease caused by a deficiency of galactose-1-phosphate uridyltransferase

necessary for the metabolism of the galactose derived from milk lactose. The condition should b

infants with growth failure, cataracts, liver disease, aminoaciduria, and mental retardation. A re(galactose) is usually present in the urine. Most of the pathology is related to the toxic effects o

phosphate. Treatment involves strict dietary lactose restriction, which consists of more than sim

of milk products, because lactose is also present in many non-diary foods. Strict adherence to th

strikingly alter the course of this disease.

Cystic fibrosis (choice A) is associated with maldigestion, pancreatic disease, and pulmonary di

McArdle's disease (choice C) is a glycogen storage disease that selectively affects muscle.

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Von Gierke's disease (choice D) is a glycogen storage disease affecting the liver and kidneys.

Wilson's disease (choice E) is a caused by a metabolic abnormality in the handling of copper tha

cirrhosis and brain damage, and usually presents in adolescence.

--------------------------------------------------------------------------------

6The correct answer is B. The adult form of aortic coarctation is caused by stenosis in the aortito the left subclavian artery. This leads to hypertension proximal to, and hypotension distal to,

segment. Hypertension in the upper part of the body manifests with headache, dizziness, and o

symptoms. Hypotension in the lower part of the body results in signs and symptoms of ischemi

claudication, i.e., recurrent pain due to ischemia of leg muscles. In addition, collateral arteries b

precoarctation and postcoarctation aorta (eg, the intercostal and internal mammary arteries) e

establish communication between aortic segments proximal and distal to stenosis. Enlarged int

produce notching of the inferior margins of the ribs, which can be detected on x-ray and is diag

condition. Remember that the infantile form of aortic coarctation is associated with patent duct

whereas the adult form is not.

Aortic valvular stenosis (choice A) at this age would most likely be caused by a congenitally ma

usually a valve with two cusps or a single cusp. Aortic stenosis manifests with systolic hypotenssyncope, and hypertrophy/dilatation of the left ventricle. Low systolic pressure is present in th

The isolated form of patent ductus arteriosus (choice C) leads to shunting of blood from the aor

vessel) to the pulmonary artery (low-pressure vessel). Eventually, chronic cor pulmonale devel

resultant right-sided heart failure.

Pulmonary valvular stenosis (choice D) is a rare form of congenital heart disease that leads to c

pulmonale and heart failure.

Vasculitis involving the aortic arch (choice E) is found in Takayasu arteritis, in which chronic in

changes develop in the aortic arch and its branches (brachiocephalic trunk, left common caroti

subclavian arteries). This condition causes stenosis of these arteries; therefore, there will be sig

symptoms of ischemia to the upper part of the body. Since the radial pulses are very weak or ab

disorder is also known as pulseless disease.--------------------------------------------------------------------------------7The correct answer is B. The tu

is probably a glomus tumor, which is a benign tumor notorious for producing pain far out of pr

small size. The question is a little tricky (but important clinically for obvious reasons) because

the most distal aspect of the dorsal skin of the fingers, including the nail beds, is innervated by

nerves rather than the dorsal digital nerves. Specifically, the median nerve through its palmar d

supplies the nail beds of the thumb, index finger, middle finger, and half of the ring finger.

The axillary nerve (choice A), musculocutaneous nerve (choice C), and radial nerves (choice D)

nail beds.

The radial nerve does supply the more proximal skin of the back of the index finger. The ulnar n

supplies the nail beds of the small and half of the ring finger.

--------------------------------------------------------------------------------8.The correct answer is C. The Bachromatin body, is an inactivated X chromosome seen as a small, perinuclear, dark-staining dot

with two or more X chromosomes. Barr bodies are seen in any individual born with at least two

including normal females. (47, XXY), the classic karyotype of Klinefelter's syndrome, is defined

hypogonadism due to the presence of a Y chromosome and two or more X's. As in normal fema

chromosomes becomes a Barr body in Klinefelter's syndrome.

Classic Turner syndrome females (choice A) and genotypically normal males (choice D) have on

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chromosome. Thus, no X chromosome is inactivated, and somatic cells do not show any Barr bo

(47, XY+1Cool is the karyotype of an Edward's syndrome (choice B) fetus. Although this trisom

associated with a characteristic syndrome of physical abnormalities, there is no programmed in

extra chromosome 18. Thus, no Barr body is produced.

XYY syndrome (choice E) is not associated with inactivation of any X chromosomes, so Barr bodpresent. Like a trisomy involving any of the non-sex-linked chromosomes, the duplicated chrom

expressed in its entirety.

--------------------------------------------------------------------------------9The correct answer is E. This hi

typical for subdural hematoma. Usually, the patient is elderly or alcoholic and has some degree

causing the brain to pull slightly away from the skull. This stretches the bridging (penetrating)

the skull to connect to the cranial venous sinuses, leaving them very vulnerable to rupture after

trauma. This type of hematoma is due to venous, rather than arterial, hemorrhage and thus ten

rather slowly.

Epidural hematoma (choice A) is seen following severe head trauma causing laceration of the m

artery.

Mixed parenchymal and subarachnoid hemorrhage (choice B) can be seen with bleeding from AMultiple tiny hemorrhages of the putamen (choice C) are intraparenchymal hemorrhages assoc

hypertension.

Subarachnoid hemorrhage (choice D) can be seen with bleeding from ruptured berry aneurysm

--------------------------------------------------------------------------------10The correct answer is E. The r

laryngeal nerves are branches of the vagus (CN X), and supply all intrinsic muscles of the larynx

cricothyroid. The right recurrent laryngeal nerve recurs around the right subclavian artery. Th

laryngeal nerve recurs in the thorax around the arch of the aorta and ligamentum arteriosum. B

ascend to the larynx by passing between the trachea and esophagus, in close proximity to the th

recurrent laryngeal nerves are therefore particularly vulnerable during thyroid surgery, and da

extreme hoarseness.

The facial nerve (choice A) innervates the muscles of facial expression, the stapedius muscle, ansubmandibular and sublingual glands. It also mediates taste sensation from the anterior two-th

tongue.

The glossopharyngeal nerve (choice B) innervates the stylopharyngeus muscle and the parotid

afferents supply the carotid sinus baroreceptors and carotid body chemoreceptors, and mediat

posterior one-third of the tongue. Somatosensory fibers supply pain, temperature, and touch in

the posterior one-third of the tongue, upper pharynx, middle ear, and eustachian tube.

The hypoglossal nerve (choice C) innervates the intrinsic muscles of the tongue, the geniogloss

and styloglossus muscles.

The trigeminal nerve (choice D) receives sensory information from the face and also innervates

mastication.

--------------------------------------------------------------------------------11The correct answer is B. Charborderline personality disorder include frantic behavior to avoid abandonment, unstable interp

relationships, alternating between idealization and devaluation (splitting), recurrent suicidal g

types of self-mutilatory behavior, feelings of emptiness, and inappropriate intense anger.

An antisocial patient (choice A) does not confirm to social norms, is deceitful, impulsive, reckle

and lacks remorse for wrongdoings.

One symptom that would suggest histrionic personality disorder (choice C) in this patient is he

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exaggeration of her emotions by talking while lying on the floor. A histrionic patient might pres

attention-seeking and/or seductive and provocative behavior, but the presence of splitting, rec

gestures and anger argue strongly for the diagnosis of borderline personality disorder.

A narcissistic patient (choice D) is grandiose and preoccupied with success, feels special and re

admiration, feels entitled, takes advantage of others, lacks empathy, and is arrogant.A schizoid patient (choice E) is usually not interested in relationships or pleasurable activities,

friends, is emotionally cold, and is indifferent to praise or criticism.

--------------------------------------------------------------------------------12The correct answer is C. This p

hypertrophic cardiomyopathy-the most common cause of sudden cardiac death in young patien

causes problems during exertion. Clues to the diagnosis include: dyspnea, palpitations, bifid ap

coarse systolic murmur at the left sternal border, and ventricular hypertrophy with asymmetri

thickening on echocardiogram. Left ventricular outflow obstruction typically plays an importan

pathophysiology of this condition. Maneuvers that decrease preload, such as the Valsalva mane

accentuate the heart murmur because they result in less ventricular filling, contributing to grea

obstruction.

Elevating his legs (choice A), increasing sympathetic tone (choice B), and squatting (choice D) wvenous return and would therefore diminish the murmur.

--------------------------------------------------------------------------------13The correct answer is E. The s

symptoms in this patient are consistent with occlusion of the posterior inferior cerebellar arter

a branch of the vertebral artery (which is itself a branch of the subclavian artery). Occlusion of

lateral medullary syndrome characterized by deficits in pain and temperature sensation over th

body (spinothalamic tract dysfunction); ipsilateral dysphagia, hoarseness, and diminished gag r

(interruption of the vagal and glossopharyngeal pathways); vertigo, diplopia, nystagmus, and v

(vestibular dysfunction); ipsilateral Horner's syndrome (disruption of descending sympathetic

ipsilateral loss of pain and temperature sensation of the face (lesion of the spinal tract and nucl

trigeminal nerve).

AICA (choice A) is a branch of the basilar artery. Occlusion of this artery produces a lateral infesyndrome, which is characterized by ipsilateral facial paralysis due to a lesion of the facial nucl

cochlear nucleus damage leading to sensorineural deafness, vestibular involvement leading to

spinal trigeminal involvement leading to ipsilateral pain and temperature loss of the face. Also,

ipsilateral dystaxia due to damage to the middle and inferior cerebellar peduncles.

The anterior spinal artery (choice B) is a branch of the vertebral artery. Occlusion produces the

medullary syndrome, characterized by contralateral hemiparesis of the lower extremities and t

corticospinal tract involvement. Medial lemniscus involvement leads to diminished propriocep

contralateral side, and ipsilateral paralysis of the tongue ensues from damage to the hypoglossa

The MCA (choice C) is a terminal branch of the internal carotid artery. Occlusion results in cont

arm paralysis and sensory loss. Aphasia is produced if the dominant hemisphere is affected, lef

ensues if the right parietal lobe is affected, and quadrantanopsia or homonymous hemianopsiais damage to the optic radiations.

The PCA (choice D) arises from the terminal bifurcation of the basilar artery. Occlusion results

hemianopsia of the contralateral visual field. Often, there is macular sparing.

--------------------------------------------------------------------------------14The correct answer is C. The d

of necrosis described in the question stem are border zone (watershed) infarcts. They occur as

severe ischemia, which most profoundly affects the relatively poorly perfused areas at the boun

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major arterial territories. The areas of necrosis described in the question stem are those most c

observed, although similar infarcts involving border zones in the brain stem are sometimes als

Bacterial infection (choice A) tends to produce either meningitis, cerebritis, or localized infectio

abscesses.

Fungal infection (choice B) tends to produce either meningitis, vasculitis, granulomas, or absceTumor (choice D) tends to produce localized masses.

Viral infection (choice E) may have a variety of patterns, including meningitis, diffuse encephal

necrosis, but would not be expected to produce a distinctive linear pattern.

--------------------------------------------------------------------------------15The correct answer is E. The m

primary cardiac tumor of adults is atrial myxoma, which typically occurs as a single lesion in th

may intermittently obstruct the mitral valve. Histologically, these tumors are composed of scatt

mesenchymal cells in a prominent myxoid background.

Benign glandular tissue (choice A) suggests an adenoma, which is not usually found in the hear

Densely packed smooth muscle (choice B) suggests a leiomyoma, which is not usually found in

Densely packed striated muscle (choice C) suggests rhabdomyoma, which is the most common

tumor in children, not adults.Malignant glandular tissue (choice D) suggests carcinoma, which can be metastatic to the heart

usually cause a ball-valve obstruction.

--------------------------------------------------------------------------------16The correct answer is D. Comp

indicate advanced atherosclerotic disease. They arise in atherosclerotic plaques, and render the

susceptible to sudden occlusion and acute infarction of the supplied tissues. Commonly, the pla

ruptures, and the exposed surfaces, being highly thrombogenic, precipitate thrombus formation

typified by the lines of Zahn, alternating layers of platelets and fibrin (the pale lines) and layers

dark lines). Beyond thrombus formation, other features of a complicated plaque include hemor

lesion itself, and microembolism by cholesterol crystals or calcified debris. Furthermore, the w

underlying the plaque may develop an aneurysmal dilatation. In general, the clinical significanc

atherosclerosis is related to the consequences of complicated lesions.The incorrect options all include features of atheromatous plaques, but do not indicate complic

Beneath the endothelium of a plaque there is a fibrous cap composed of smooth muscle (choice

inflammatory cells (choice B) and lipid laden macrophages (foam cells), as well as extracellular

The core of the lesion, which lies between the intima and the media, is composed of necrotic ce

(choice E), with cholesterol crystals (choice A), calcium, and more foam cells.

--------------------------------------------------------------------------------

17The correct answer is B. This patient is suffering from internuclear ophthalmoplegia (INO), w

a lesion of the medial longitudinal fasciculus (MLF). The medial longitudinal fasciculus (MLF) c

oculomotor (III), trochlear (IV), and abducens (VI) nuclei and is essential for conjugate gaze. A l

will result in the inability to medially rotate the ipsilateral eye on attempted lateral gaze. Howe

the motor fibers of the right oculomotor nerve would also lead to the same symptoms. The waydistinguish between an INO from a lesion of the medial rectus muscle or a lesion of the motor fi

to determine whether the patient can converge her eyes. If the innervation of the medial rectus

interrupted, the patient will not be able to move the ipsilateral eye medially for either conjugat

(convergence) movements. However, if the lesion is in the MLF, this would only affect conjugat

not convergence, asin this patient.

The left oculomotor nerve (choice A) is intact because the light reflexes are normal, and there i

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of any eye movement disorders of the left eye.

A lesion of the right abducens nerve (choice C) would result in paralysis of the lateral rectus mu

lead to an inability to abduct the right eye.

The right oculomotor nerve (choice D) innervates the medial rectus muscle, which would lead t

adduct the right eye when looking toward the left. (CN III also innervates the superior rectus, ininferior oblique extraocular muscles.) However, a patient with a lesion of this nerve would also

converge. A patient with a lesion of CN III would also be expected to have the affected eye look

because of the unopposed actions of the lateral rectus and superior oblique muscles, and ptosis

denervation of the levator palpebrae muscle. Additionally, a lesion of the right oculomotor nerv

light reflexes and produce mydriasis if the parasympathetic fibers of this nerve were damaged.

The trochlear nerve (choice E) innervates the superior oblique muscle, which depresses, intort

eye. A lesion of this nerve theoretically could produce a slight extorsion of the eye and a weakn

gaze. However, a lesion of this nerve often produces only minimal symptoms because of the pre

muscles that are innervated by the unaffected oculomotor nerve, and because of a compensator

--------------------------------------------------------------------------------18The correct answer is E. The m

passes through the foramen ovale and may be injured by this fracture. The mandibular nerve isthe innervation of all of the muscles of mastication: the masseter, the temporalis, the medial pte

lateral pterygoid muscles.

Abduction of the eye (choice A) is produced by the lateral rectus muscle, which is innervated by

nerve. The abducens nerve leaves the cranial cavity and enters the orbit by passing through the

fissure.

Sensation in the skin over the forehead (choice B) is provided by the ophthalmic division of the

The ophthalmic division leaves the cranial cavity and enters the orbit by passing through the su

fissure.

Sensation in the skin over the zygoma (choice C) is provided by the maxillary division of the tri

The maxillary division leaves the cranial cavity and enters the pterygopalatine fossa by passing

foramen rotundum.Taste sensation on the anterior 2/3 of the tongue (choice D) is provided by the chordae tympan

facial nerve. The facial nerve leaves the cranial cavity and enters the temporal bone by passing

auditory meatus. The chordae tympani leave the temporal bone and enter the infratemporal fo

through the petrotympanic fissure.

--------------------------------------------------------------------------------19The correct answer is C. The m

is called "paradoxical movement" and occurs when a portion of the ventricular wall is infarcted

longer contract during systole. The site of infarction described is in the distribution of the left a

descending artery.

Valvular disease, including that of the aortic valve (choice A), mitral valve (choice D), or tricusp

E) will not cause localized paradoxical movement.

The circumflex artery (choice B) supplies the superior part of the posterior wall of the heart, anwith the right coronary artery.

--------------------------------------------------------------------------------20The correct answer is D. Paste

is a gram-negative rod that is normal flora of the oral cavity of dogs and cats. It often causes a lo

following introduction under the skin by an animal bite. Most cases occur in children who are in

playing with a pet.

Bartonella henselae (choice A) is a very small, gram-negative bacterium that is closely related t

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although it is able to grow on lifeless media. It is the cause of cat-scratch disease (a local, chron

most commonly seen in children) and bacillary angiomatosis (seen particularly in AIDS patient

patient population, the organism causes proliferation of blood and lymphatic vessels causing a

"mulberry" lesion in the skin and subcutaneous tissues of the afflicted individual.

Brucella canis (choice B) is a gram-negative rod that is a zoonotic agent. Its normal host is the dgains access to humans, it causes an undulating febrile disease with malaise, lymphadenopathy

hepatosplenomegaly. The normal route of exposure is via ingestion of the organism.

Clostridium tetani (choice C) is a gram-positive spore-forming anaerobic rod. It causes tetanus

paralysis caused by tetanospasmin, which blocks the release of the inhibitory neurotransmitter

gamma-aminobutyric acid [GABA]). There may be no lesion at the site of inoculation, and exuda

extremely rare.

Toxocara canis (choice E), a common intestinal parasite of dogs, is a metazoan parasite that cau

migrans. Young children are most likely to be affected, as they are most likely to ingest soil cont

eggs of the parasite

--------------------------------------------------------------------------------21The correct answer is B. After

meal, triglycerides are processed by the intestinal mucosal cells. They are assembled in chylomeventually sent into the circulation for delivery to adipocytes and other cells. Chylomicrons are

cells, but are degraded while in the circulation by lipoprotein lipase. A defect in this enzyme wo

accumulation of chylomicrons in the plasma.

Albumin-bound free fatty acids (choice A) is incorrect because fatty acids leave the intestine es

triglycerides in chylomicrons.

HDL (choice C) is not a carrier of dietary fat from the intestine.

LDL (choice D) would be not be elevated in this patient after a high fat meal. However, VLDL wo

the patient ate a high carbohydrate meal. In this situation, the carbohydrate would be converte

liver and sent out into circulation as VLDL. VLDL would be unable to be degraded to LDL and, th

accumulate.

A defect in lipoprotein lipase would cause a decrease, not an elevation of unesterified fatty acidthe chylomicrons contain esterified fatty acids.

--------------------------------------------------------------------------------22The correct answer is D. The T

Apperception test is a projective test employing pictures depicting ambiguous interpersonal sit

examinee is asked to interpret. Psychodynamic theory suggests that since the stimuli are vague

projects his or her own thoughts, feelings, and conflicts into his or her responses, providing the

into the patient's thought and memory content.

The Minnesota Multiphasic Personality Inventory (MMPI; choice A), which uses true and false i

popular objective personality test.

The Myers-Briggs Personality Inventory (choice B) is based on Jungian theory and assesses bas

personality (extroversion); it is used extensively in occupational counseling. The patient selects

adjectives from groups of choices.The Rorschach Test (choice C) is another projective test that involves asking patients to describ

when presented with a series of black and white inkblots.

The Type A and B Behavior Patterns Test (choice E) assesses the amount of "driven quality" a p

life. Type A's are always "running out of time." This is a verbal test that resembles an interview

--------------------------------------------------------------------------------23The correct answer is A. Arrow

inner mitochondrial membrane. Carnitine acyltransferase II is located on the inner face of the in

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mitochondrial membrane. It reforms fatty acyl CoA in the mitochondrial matrix (arrow 5) from

thus preparing it for mitochondrial oxidation. The acyl groups on carnitine are derived from ac

synthesized in the outer mitochondrial

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