Deck 1: Introduction

Question 1

In an elite marathon runner, performance in a marathon race is limited by a number of factors. Among world class marathon runners, which of the following factors is considered to be critical for a high level of performance?

A) Muscle ATP content
B) Adequate fat stores
C) High muscle glycogen content
D) High muscle oxidative capacity
E) High percentage of type II muscle fibers

Answer 1

High muscle oxidative capacity

Question 2

A 45-year-old woman complains of episodic epigastric pain. She denies fevers, chills, diaphoresis, flushing, chest pain or shortness of breath. An upper endoscopy reveals severe and atypical peptic ulcer disease. Biopsy results are Helicobacter pylori negative and she denies taking NSAIDs. Continued workup should include serum levels of which of the following?

A) Serotonin
B) Gastrin
C) Vasoactive intestinal peptide (VIP)
D) Cholecystokinin (CCK)
E) Histamine

Answer 2

Gastrin

Question 3

Your 74-year-old male patient suffers from hyperthyroidism. Hyperthyroid individuals characteristically exhibit:

A) Heat tolerance
B) A low basal metabolic rate (BMR)
C) Decreased peripheral resistance
D) Dry, yellowish skin
E) High plasma cholesterol levels

Answer 3

Decreased peripheral resistance

Question 4

An 18-year-old male complains about continuous growth, lack of facial hair, small genitalia and lack of muscle development. Laboratory values include total testosterone 125 ng/dL (normal 300-1100 ng/dL) and luteinizing hormone (LH) < 2 mIU/mL (normal 6-23 mIU/mL). A major causal factor in some cases of hypogonadism is:

A) Increased number of follicle stimulating hormone (FSH) receptors in the testis
B) Hypersecretion of pituitary LH and FSH as the result of increased gonadotropin-releasing hormone (GnRH)
C) Excess secretion of testicular activin by Sertoli cells
D) Failure of the hypothalamus to respond to testosterone
E) Reduced secretion of GnRH

Question 5

A 79-year-old woman presents to the emergency department with right lower quadrant abdominal pain of several hours' duration. She has a temperature of 101.7º C and has tenderness to palpation in the right lower quadrant of her abdomen. Abdominal computed tomography (CT) scan reveals diverticulitis of the colon. Where are diverticula most frequently found in the colon?

A) Cecum
B) Ascending colon
C) Transverse colon
D) Descending colon
E) Sigmoid colon

Question 6

You see a 78-year-old man in clinic for his annual physical. He reports excellent health. During your review of systems, he admits to having difficulty initiating his urine stream, nocturia, and occasionally feels as if he does not completely empty his bladder. Routine lab tests show a normal level of prostate-specific antigen (PSA). Analysis shows no hematuria or crystalluria. What related finding might you anticipate when you move on to his physical exam?

A) Testicular atrophy
B) Urinary calculi (stones) blocking the urethra
C) Hypospadias
D) Irregular prostatic nodularity
E) Uniformly smooth prostatic enlargement

Question 7

A 58-year-old woman with type II diabetes mellitus was diagnosed approximately 1 year ago. Her labs show no improvement in blood glucose control over the ensuing months despite treatment. What test should you order to examine her average blood sugar levels over the past few months?

A) Fasting blood glucose
B) Two-hour glucose tolerance test
C) Hemoglobin
D) Hemoglobin A_lc
E) Hemoglobin S

Question 8

A 14-year-old male soccer player complains of occasional shortness of breath, particularly during practice or games. You decide to initially treat his asthma with a β₂ agonist inhaler to be used when symptoms appear. By which mechanism will this agent improve his ability to breathe?

A) Bronchodilation via smooth muscle relaxation
B) A decrease of pro-inflammatory cells
C) Prevention of histamine release
D) Inhibition of leukotriene synthesis
E) Leukotriene-l receptor antagonism

Question 9

Lidocaine, a use-dependent blocker of voltage-gated Na⁺ channels, is an effective antiarrhythmic because its blocking effect becomes greater when:

A) The drug is repeatedly used.
B) Na⁺ channels are activated repeatedly at a high frequency.
C) Na⁺ channels are activated repeatedly at a low frequency.
D) Na⁺ channels are closed.
E) The extracellular Na⁺ concentration is high.

Question 10

A middle-aged obese man complains of increasing frequency of headaches and worsening visual acuity. Although his headache pain is usually relieved by over-the-counter pain relievers, the discomfort returns after a few hours. An ophthalmoscopic examination reveals bilateral flame hemorrhages and cotton-wool spots. What laboratory measurement would confirm the likely cause of this man's headaches and worsening sight?

A) Serum glucose level
B) Hemoglobin A_lc
C) Toxicology screen including methanol
D) Serum vitamin A level
E) Blood pressure

Question 11

A 56-year-old retired schoolteacher presents with progressive dysphagia, substernal pain with eating, and weight loss over the course of 1 year. He has never traveled outside the United States. Barium esophagography reveals esophageal dilation, lack of esophageal peristalsis, and a 'bird's beak' tapering of the distal esophagus. Which of the following is a likely cause of this patient's condition?

A) Achalasia
B) Zenker's diverticulum
C) Barrett's esophagus
D) Chagas disease
E) Increased pressure of the upper esophageal sphincter

Question 12

A 17-year-old girl comes to see an endocrinologist because of primary amenorrhea. Breast development started several years ago, and she has otherwise been well. On examination breast development and height is in the tenth percentile, but she has no pubic or axillary hair. A pelvic examination reveals a blind vagina. These findings are most consistent with which of the following?

A) Turner's syndrome
B) Hypopituitarism
C) Androgen insensitivity
D) Klinefelter's syndrome
E) Adrenogenital syndrome

Question 13

Your 55-year-old female patient suffers from osteoporosis. For treatment you decide to use an antiresorptive agent currently used for treatment of osteoporosis:

A) Increasing parathyroid hormone (PTH) secretion
B) Inhibiting calcitonin release
C) Decreasing the remodeling space of bone
D) Stimulating estrogen synthesis
E) Blocking 1α-hydroxylase activity

Question 14

A 60-year-old man presents to your office with facial flushing and abdominal cramps and diarrhea. The workup reveals an elevated level of urinary 5-hydroxyindoleacetic acid (5-HIAA), and subsequently, elevated levels of 5-HIAA in a 24-hour urine collection. What is the most likely diagnosis?

A) Zollinger-Ellison syndrome
B) Cushing's syndrome
C) Malignant carcinoid syndrome
D) Vipoma
E) Glucagonoma

Question 15

A 30-year-old woman with severe Crohn's disease is taken to surgery for an ileal resection. What nutritional deficiency does this woman risk in the future?

A) Folate deficiency
B) Niacin deficiency
C) Thiamine deficiency
D) Iron deficiency
E) Vitamin B₁₂ deficiency

Question 16

A 65-year-old woman with a history of congestive heart failure, osteoarthritis, and hypertension presents with pain and tenderness, which is relieved by food or antacids. Upper endoscopy reveals a gastric ulcer. Her current medications include digoxin, metoprolol, lisinopril, aspirin, and hydrochlorothiazide. Which of her medications is most likely to have contributed to her peptic ulcer disease?

A) Digoxin
B) Metoprolol
C) Lisinopril
D) Aspirin
E) Hydrochlorothiazide

Question 17

A 67-year-old man presents with mild dysphagia and throat discomfort that has slowly progressed over the past 5 years. He reports waking up at night choking and regurgitating undigested food. He has been troubled by halitosis and has noticed a small protrusion in his neck over the past year. He denies weight loss or heartburn. Which of the following is most consistent with his symptoms?

A) Achalasia
B) Zenker's diverticulum
C) Gastroesophageal reflux disease
D) Schatzki's ring
E) Esophageal cancer

Question 18

In skeletal muscle during a contraction cycle:

A) Myosin-ATP complex has a high affinity for actin.
B) Tropomyosin binds calcium.
C) The rigor complex is broken by the binding of ADP to myosin.
D) ATP hydrolysis provides the energy required for myosin flexure in the 'hinge regions'.
E) The T tubules take up calcium via an active transport mechanism.

Question 19

A 47-year-old woman with a longstanding history of heartburn complains of severe heartburn. You make the diagnosis of gastroesophageal reflux disease (GERD). An upper endoscopy study is positive for Barrett's esophagus. Which of the following correctly describes Barrett's esophagus?

A) Replacement of the squamous epithelium of the esophagus with columnar epithelium
B) Replacement of the columnar epithelium of the esophagus with squamous epithelium
C) The presence of moderate-to-high grade dysplasia in the esophagus
D) The presence of low-to-moderate grade dysplasia in the esophagus
E) The presence of any stricture within the esophagus

Question 20

Which if the following is true about voltage-gated Na⁺ channels in the axon?

A) They remain open as long as the membrane is sufficiently hyperpolarized.
B) They remain open as long as the membrane is sufficiently depolarized.
C) They remain open for only a short period of time after the cell is sufficiently depolarized.
D) They belong to a family of channels that are made of five subunits.
E) They have about the same relative permeability ratio (P_Na/P_K) as ACh channels.

Question 21

Certain tumor cells are known to have a plasma membrane Na⁺ channel that is activated by acidic extracellular pH. In these cells, if acid is added to the extracellular medium, the:

A) Membrane potential will hyperpolarize.
B) Rate of ATP utilization will increase.
C) Cells will shrink.
D) Na⁺ K⁺-ATPase will become inactivated.
E) K⁺ efflux will decrease.

Question 22

A 1-year-old infant is brought to the pediatrician with lethargy, a poor suck, and feeding reflux days after eating home-canned peaches. You suspect Clostridium botulinum poisoning. What is the mechanism of the toxin responsible for this child's symptoms?

A) Toxin causes convulsive contractions of skeletal muscle.
B) Toxin blocks release of acetylcholine at synapses.
C) Exfoliative toxin causes separation of granular epidermal cells.
D) Enterotoxin causes stimulation of ADP ribosylation.
E) Protein causes pore formation in epithelial cell membranes.

Question 23

A 26-year-old man comes to the emergency room complaining of lethargy, headache, nausea and extreme, weakness. His skin has a cherry-red color. He has a normal arterial PO₂, but a low venous PO₂ of 20 mmHg (normal is 40 mmHg). You believe this situation is caused by:

A) Cyanide poisoning
B) Absolute right-to-left cardiopulmonary shunt
C) A right-shifted hemoglobin
D) Hypoventilation
E) Carbon monoxide poisoning

Question 24

Al and Zack are twins with end-stage renal failure due to Alport syndrome. Both are on chronic dialysis and make no urine. Following dialysis, they both weigh the same and have identical serum osmolalities. On the way home from a dialysis session, they stop at Vino's for lunch. Al drinks 1 liter of pale ale and eats a pepperoni calzone (sodium content 140 mEq). Zack, the designated driver, isn't hungry but drinks 2 liters of lager. When (if) they arrive home, which of the following statements would be true?

A) Zack's total body water is less than Al's.
B) Zack's serum osmolality is greater than Al's.
C) Zack's intracellular fluid (ICF) volume is greater than Al's.
D) Zack's extracellular fluid (ECF) volume is greater than Al's.
E) Zack's plasma sodium level is greater than Al's.

Question 25

A 59-year-old morbidly obese female patient is diagnosed with a restrictive lung disease that causes lung compliance to be half the normal value. If tidal volume and breathing rate are normal, then:

A) Total work of breathing is twice normal.
B) Airway resistance is twice normal.
C) Pleural pressure at end-inspiration is more negative than normal.
D) Alveolar pressure at end-inspiration is positive.
E) The functional reserve capacity (FRC) is increased.

Question 26

An 70-year-old man complains of lower back pain that is accompanied with strong muscle spasms. He is otherwise healthy. Which of the following drugs might be effective in reducing the magnitude of the spasms?

A) A drug that inhibits Ca²⁺ release from the sarcoplasmic reticulum
B) A drug that inhibits myosin light chain kinase
C) A drug that blocks Ca²⁺ channels in the cell membrane
D) An acetylcholinesterase inhibitor
E) An inhibitor of skeletal muscle glucose uptake

Question 27

An individual has arterial hypoxemia; PaO₂ = 50 mmHg. Which possible cause of this hypoxemia would cause the largest elevation in arterial PCO₂?

A) High altitude
B) Diffusion impairment
C) Physiological shunt
D) Pulmonary embolism
E) Hypoventilation

Question 28

A 24-year-old pregnant woman complains of right-sided facial drooping, particularly of her right eyelid and the corner of her mouth. She describes herself as being healthy. What cranial nerve has most likely been affected?

A) Trigeminal nerve (CN V)
B) Abducens nerve (CN VI)
C) Glossopharyngeal nerve (CN IX)
D) Facial accessory nerve (CN XI)
E) Facial nerve (CN VII)

Question 29

A patient presents with a urine flow (V), of 12 L/day. You find that plasma osmolality (P_OSM) is above normal and that plasma AVP levels are very low. Based on this information, and given the following choices, what is your best diagnosis for this patient?

A) Hypothalamic (central) diabetes insipidus
B) Nephrogenic diabetes insipidus
C) Diabetes mellitus
D) Polydipsic diabetes insipidus
E) Diabetes macula densa

Question 30

A 56-year-old man presents with a 4-day history of impaired vision. On physical exam, you note a loss of vision of his left visual field in both eyes. The patient most likely has a lesion involving the:

A) Right optic nerve
B) Optic chiasm
C) Right optic tract
D) Right temporal lobe
E) Right parietal lobe

Question 31

A 2-year-old Caucasian boy is brought to the pediatric clinic for failure to gain weight. The child's mother states that he has frequent foul-smelling stools, with a greasy appearance, and has had three hospitalizations for pneumonia. Which of the following defects is responsible for this child's symptoms?

A) Lack of phenylalanine hydroxylase
B) Deficiency of galactokinase
C) Defective epithelial chloride transport
D) Amino acid substitution on the hemoglobin beta chain
E) Defect in hypoxanthine-guanine phosphoribosyltransferase

Question 32

Your patient has normal function of the diaphragm but has a spinal injury that completely prevents any activity of abdominal or intercostal muscles. In this patient you expect to find that:

A) Residual volume is smaller than normal.
B) Vital capacity equals total lung capacity.
C) Intrapleural pressure is positive during expiration.
D) Transpulmonary pressure is negative during expiration.
E) Alveolar pressure is positive during expiration.

Question 33

A 7-year-old patient with cystic fibrosis (CF) has a 4-week history of greasy, foul smelling diarrhea. In which of the following vitamins or minerals would he be most likely to be deficient?

A) Iron
B) Vitamin B₆
C) Vitamin C
D) Vitamin K
E) Folic acid

Question 34

A sudden ascent to high altitude (e.g. atmospheric pressure half that at sea level) will, in the first several hours, cause:

A) Hypoxic stimulation of central chemoreceptors
B) A decrease in the pH of the fluid surrounding the central chemoreceptors
C) An increase in alveolar to arterial PO₂ difference
D) Hypoxic stimulation of carotid body chemoreceptors
E) A decrease in pulmonary arterial blood pressure

Question 35

A 19-year-old male presents to the emergency department with headache, neck stiffness and fever. You are concerned about bacterial meningitis. What are the classical laboratory findings for CSF in bacterial meningitis?

A) Decreased glucose; decreased protein; many polymorphonuclear leukocytes
B) Normal glucose; elevated protein; many polymorphonuclear leukocytes
C) Elevated glucose; decreased protein; many polymorphonuclear leukocytes
D) Decreased glucose; elevated protein; many polymorphonuclear leukocytes
E) Elevated glucose; elevated protein; many lymphocytes

Question 36

You see a 52-year-old markedly obese man in clinic who complains of arthritic pain in the knees, but otherwise reports no significant health problems. On physical exam you notice a darkening of his skin along the back of his neck, at the folds of his axillary skin, and faintly in the groin area and behind his knees. He states that he has had these darker areas for 'quite a long time'. What laboratory test would be most helpful in confirming your suspicions of his metabolic disorder?

A) Serum blood glucose
B) Thyroid stimulating hormone (TSH)
C) Parathyroid hormone (PTH)
D) Uric acid
E) Urine vanillylmandelic acid (VMA)

Question 37

A 30-year-old female with a past medical history of having a baby born with a myelomeningocele plans to become pregnant. She is concerned about the possibility of having another child with this condition and asks what she can do to help prevent the defect from occurring again. Which of the following dietary supplements would you recommend?

A) Vitamin A
B) Vitamin B₁₂
C) Folic acid
D) Iron
E) Vitamin K

Question 38

A 68-year-old man is brought to your emergency room in July after concerned neighbors, who had not seen him for several days, found him collapsed on his living room floor. The temperature inside the house was about 105^o F. The patient was barely arousable. His body temperature is 40^o C, his skin and mucus membranes are dry, and his blood pressure is low. Which of the following laboratory results would you expect to find?

A) Elevated aldosterone level
B) Decreased renin level
C) Elevated urine Na⁺ concentration
D) Decreased antidiuretic hormone (ADH) levels
E) Low urine osmolality

Question 39

A 49-year-old male presents to the emergency department with intermittent abdominal pain and nausea for the past week. He is worried that he has a duodenal ulcer. Which of the following is correct regarding duodenal ulcers?

A) Characterized by epigastric pain that worsens with eating
B) Less than 20% are associated with Helicobacter pylori infection
C) Incidence is greater in smokers.
D) It is unrelated to consumption of nonsteroidal anti-inflammatory drugs (NSAIDs)
E) Peak incidence is at 60 years of age

Question 40

A 55-year-old homeless man presents to the emergency room and is noted to have bleeding gums. He has several ecchymoses over his shins and forearms. A complete blood count shows hemoglobin of 11 g/dL and an elevated mean corpuscular volume (MCV). Which vitamin deficiency is responsible for his symptoms?

A) Vitamin A
B) Vitamin B₁₂
C) Vitamin C
D) Vitamin D
E) Vitamin E

Question 41

A particular epithelium has a paracellular (between the cells) pathway permeable to water and chloride. In order to enhance the net movement of NaCl and water from apical to basolateral portions of the cell, the epithelium needs:

A) Basolateral Na⁺K⁺-ATPase, basolateral K⁺ channels, and apical Na⁺ channels
B) Apical Na⁺K⁺-ATPase, apical K⁺ channels, and basolateral Na⁺ channels
C) Basolateral Na⁺K⁺-ATPase, apical K⁺ channels, and basolateral Na⁺ channels
D) Apical Na⁺K⁺-ATPase, basolateral K⁺ channels, and apical Na⁺ channels
E) Basolateral Na⁺K⁺-ATPase, basolateral K⁺ channels, and basolateral Na⁺ channels

Question 42

Some tumor cells have a large number of Cl^- channels on the plasma membrane. This makes the Cl^- permeability higher than that of any other ion and therefore:

A) Causes the cell to swell when suspended in isotonic NaCl
B) Causes the cell to shrink when suspended in isotonic NaCl
C) Increases the steady state intracellular osmolality
D) Decreases the steady state intracellular osmolality
E) Causes the membrane potential to be near the equilibrium potential for Cl^-

Question 43

An epithelial cell layer bathed in physiological saline solution on both apical and basolateral surfaces starts out in a steady state in which there is constant absorption of Na⁺, Cl^-, and H₂O. The addition of ouabain to the basolateral side will cause:

A) Intracellular Na⁺ to rise and intracellular K⁺ to remain constant
B) Intracellular Na⁺ to fall and intracellular K⁺ to rise
C) Intracellular Na⁺ to rise and intracellular K⁺ to fall
D) Intracellular Na⁺ to remain constant and intracellular K⁺ to fall
E) Intracellular Na⁺ to remain constant and intracellular K⁺ to remain constant

Question 44

A 36-year-old male patient with a recent head injury complains of polyuria. You suspect central diabetes insipidus. How could you confirm the diagnosis?

A) Restrict water intake and treat with insulin and see if urinary volume is decreased.
B) Restrict water intake and treat with angiotensin II and see if urinary volume is decreased.
C) Restrict water intake and treat with arginine vasopressin (AVP) and see if urinary volume declines.
D) Restrict water intake and treat with a loop diuretic to determine if urinary flow rates decrease.
E) Compare urinary production rates following consumption of 3 L of water and 3 L of isotonic saline to determine whether they differ.

Question 45

A 30-year-old woman complains of extreme fatigue following even mild exercise. These symptoms become worse throughout the day. You diagnose this patient with myasthenia gravis (MG). In most patients with MG autoantibodies cause a decrease in:

A) Presynaptic action potential threshold
B) Postsynaptic action potential threshold
C) Postsynaptic (endplate) potential
D) Excitation-contraction (E-C) coupling
E) Neurotransmitter release from the nerve terminal

Question 46

Given the following data from a patient - urine output 1.5 L/day; plasma creatinine 1.0 mg/dL; urinary creatinine 1.2 mg/mL; plasma phosphate 0.002 mEq/mL; urinary phosphate 0.05 mEq/mL - what can you reliably conclude about the renal handling of phosphate?

A) There is net secretion of phosphate.
B) There is net reabsorption of phosphate.
C) Phosphate is neither secreted nor reabsorbed.
D) Phosphate is fractionally filtered.
E) The extraction ratio of phosphate is greater than 1.

Question 47

A 44 year-old male presents to the emergency department with severe back pain radiating to the left flank. A radiological exam reveals a kidney stone partially blocking the ureter of one kidney. Based on your knowledge of renal physiology, which of the following statements is correct?

A) The patient will have problems with salt and water balance due to a loss of 50% of renal function.
B) Glomerular filtration rate (GFR) in the affected kidney will decrease.
C) Urinary flow will be reduced by approximately 50%.
D) Hydrostatic pressure in the tubules will be decreased.
E) Renal failure will occur.

Question 48

Which statement is true about a 5 kg infant and his 50 kg mother?

A) The rate (mL/day) of insensible water loss is ten times as high in the mother as in the infant.
B) The water turnover rate (% total body water [TBW]/day) is the same in the infant and the mother.
C) The water turnover rate (%TBW/day) is higher in the mother than in the infant.
D) The mother has a TBW of about 42 kg.
E) The mother has an intracellular water of about 20 kg.

Question 49

Lambert-Eaton Syndrome (LES) is similar to myasthenia gravis. In LES, which of the following is most affected during neuromuscular transmission?

A) The driving force for Ca²⁺ influx in the nerve terminal
B) The synthesis of acetylcholine (ACh) in the nerve terminal
C) The release of ACh from the nerve terminal
D) The degradation of ACh in the synaptic cleft
E) The response to ACh in the muscle membrane

Question 50

A 25-year-old female medical student from out of state wants to drive home over the 4th of July holiday. She hates to use public facilities and would prefer to minimize her urinary flow rate. Unfortunately, the air conditioning in her car is broken so she knows that she will have to consume 2-3 L of fluids to replace that lost due to sweating. What is her best choice to drink during the 8-hours to result in a minimum of rest room breaks?

A) Bottled water
B) Coffee
C) Sports drinks
D) Soda
E) Sweetened tea