Comprehensive Basic Science Test

Question 1

In a steady state, the difference in CO2 content between the venous blood leaving a tissue and the arterial blood entering the tissue is determined by which of the following ratios?

Accepted Answer

Tissue CO2 production to tissue blood flow

Answer

Alveolar ventilation to tissue blood flow

Answer

Alveolar ventilation to tissue O2 consumption

Answer

Tissue CO2 production to tissue O2 consumption

Answer

Tissue CO2 production to venous PCO2

Question 2

A 16-month-old boy is brought to the physician by his mother for a well-child examination. His mother expresses concern that he did not walk until the age of 14 months, whereas his older sister walked at the age of 10 months. Physical examination shows no abnormalities. Which of the following best explains this patient’s condition?

Accepted Answer

Normal development

Answer

Autistic disorder

Answer

Child abuse

Answer

Oppositional defiant disorder

Answer

Sensory integration disorder

Question 3

A 77-year-old woman is visited by the home care nurse who notes that the patient is more lethargic than usual. Her skin and mucous membranes are dry. An increase in the serum concentration or activity of which of the following provides the strongest indication that the patient is dehydrated?

Accepted Answer

Albumin

Answer

Alkaline phosphatase

Answer

Bilirubin

Answer

Calcium

Answer

Uric acid

Question 4

A male newborn delivered at 26 weeks’ gestation develops respiratory distress immediately after a spontaneous vaginal delivery. His respirations are 40/min. Physical examination shows cyanosis and lower rib retractions with respiration. Heart sounds are normal. Bilateral breath sounds are heard on auscultation. A chest x-ray shows bilateral lung opacities. The most likely cause of this patient’s breathing difficulties is insufficient production of which of the following substances?

Accepted Answer

Surfactant

Answer

Collagen, type III

Answer

α-Fetoprotein

Answer

Meconium

Answer

Retinoic acid

Question 5

A 28-year-old woman, gravida 1, para 1, comes to the physician because of progressive fatigue since delivering a male newborn 6 months ago. She is sleeping 8 to 10 hours nightly, but she is still tired during the day. She also has not had a menstrual period since her pregnancy. Pregnancy was complicated during the third trimester by severe bleeding from placenta previa. She required multiple blood transfusions during the cesarean delivery, but she did well after the delivery. She was unable to breast-feed her newborn because of poor milk production. Which of the following is the most likely diagnosis?

Accepted Answer

Postpartum pituitary infarction

Answer

Anemia

Answer

Cardiomyopathy

Answer

Major depressive disorder

Answer

Thyroiditis

Question 6

A 12-year-old African American boy is brought to the physician by his mother because of a swollen right earlobe for 3 weeks. He had the ear pierced at a local mall 6 weeks ago. The swelling has persisted despite removal of the earring 3 weeks ago. The mother developed a thick rubbery scar on her abdomen after a cesarean delivery 12 years ago. His temperature is 37°C (98.6°F). Physical examination shows a nontender, flesh-colored swelling of the right earlobe. The skin is intact over the swelling, and it is soft and nontender. There is no cervical lymphadenopathy. Which of the following is the most likely cause of the swelling in this patient?

Accepted Answer

Keloid

Answer

Bacterial infection

Answer

Contact dermatitis

Answer

Foreign body

Answer

Lipoma

Question 7

A 5-year-old boy is brought to the physician by his parents because of an 8-month history of difficulty walking. His parents say that he limps when he walks and has a waddling gait; he also has difficulty standing. When getting up from a sitting position, he uses his hands to walk up his thighs and push his body into a standing position. His parents have not noticed any weakness of his arms. His mother is an only child, but she has an uncle who became bedridden as a child and died of respiratory arrest. Physical examination shows prominent calf muscles. Muscle strength is 4/5 at both hips but normal elsewhere. This patient most likely has a mutation in the gene coding for which of the following proteins?

Accepted Answer

Dystrophin

Answer

Actin

Answer

Frataxin

Answer

Myelin

Answer

Myosin

Question 8

A 27-year-old man comes to the physician because of pain with urination for 3 days. He has had no fever or chills. He is sexually active with three partners and does not use condoms consistently. He began having sexual relations with his most recent partner 1 week ago. His temperature is 37°C (98.6°F). Physical examination shows no abnormalities except for a clear, watery urethral discharge. Urinalysis shows 10–20 WBC/hpf but no bacteria. Which of the following is the most likely causal organism?

Accepted Answer

Chlamydia trachomatis

Answer

Entamoeba histolytica

Answer

Escherichia coli

Answer

Helicobacter pylori

Answer

Shigella flexneri

Question 9

A 20-year-old college student develops fever, severe pharyngitis, hepatosplenomegaly, and lymphadenopathy. The pathogenesis of this syndrome most likely involves a double-stranded DNA virus infection of which of the following cells?

Accepted Answer

B lymphocytes

Answer

Kupffer cells

Answer

Macrophages

Answer

Neutrophils

Answer

T lymphocytes

Question 10

A 2-year-old boy with Down syndrome is brought to the physician by his mother for a follow-up examination. His blood pressure is increased in the upper extremities and decreased in the lower extremities. Physical examination shows cyanosis of the lower extremities. An AP x-ray of the chest shows notching of the inferior surfaces of the 3rd through 8th ribs. The diagnosis of left ventricular hypertrophy is suspected. Which of the following is the most likely underlying abnormality in this patient?

Accepted Answer

Coarctation of the aorta

Answer

Atrial septal defect

Answer

Persistent truncus arteriosus

Answer

Tetralogy of Fallot

Answer

Transposition of the great arteries