10 USMLE Neurology, Physiology and Endocrine Quick Review Questions with Answers (Set 3)

These 10 quick USMLE review questions test high-yield facts that show up again and again on the exam: the adrenal medulla, the hippocampus, radial nerve injury, red cell metabolism, calcitriol, inulin clearance, folate, diabetic retinopathy, prostacyclin and calcium in hypoalbuminemia. Each question includes the correct answer.

Written by Dr. Ray Makar, MD, author of the Repeated USMLE Questions eBook series.

Prefer video? Watch daily USMLE case questions on MedFocus by Dr. Ray on YouTube.

How to use this page: read the question, pick your answer, then tap Show Answer and Explanation.

Questions

Question 1. Which one of the following structures is a part of the sympathetic nervous system but innervated by cholinergic fibers?

A- Adrenal medulla
B- Lacrimal glands
C- Renal vascular smooth muscle
D- Urinary bladder

A-Adrenal medulla- It is the only one that is a part of the sympathetic nervous system. The other choices are innervated by the parasympathetic nervous system.
The correct answer is A

 

Question 2. Anterograde amnesia is defined as inability to make new memories. Lesion of which one of the following locations may lead to this condition?

A- Amygdala
B- Basal ganglia
C- Hippocampus
D- Subthalamic nucleus

C- Hippocampus- Bilateral lesion of hippocampus leads to anterograde amnesia. Lesion of amygdala leads to disinhibited behavior. Lesion to basal ganglia may result in Parkinsonism or Huntington disease. Lesion of subthalamic nucleus may lead to contralateral hemiballismus.
The correct answer is C

 

Question 3. A football player is taken to the hospital due to broken right arm during school game. He is not able to extend his arm and his sensations on the lateral side of his hand and a portion of the first two and half digits are lost. Which one of the following nerves is most likely affected?

A- Axillary nerve
B- Median nerve
C- Radial nerve
D- Ulnar nerve

C- Radial nerve- It is the nerve responsible for innervation of the extensor muscles of the back of forearm and superficial sensation of the radial side of the arm and a portion of the lateral two and half digits.
The correct answer is C

 

Question 4. Red blood cells have abundant hemoglobin but they lack RNA and other cell organelles. Which of the following processes is the main source of ATP in RBCs?

A- Gluconeogenesis
B- Glycolysis
C- Glycogenolysis
D- Oxidative phosphorylation

B- Glycolysis- Erythrocytes don’t have mitochondria which is the site for oxidative phosphorylation so, they depend on glycolysis for the production of ATP.
The correct answer is B

 

Question 5. Which one of the following substances increases blood calcium through increasing absorption of calcium from the GI tract and distal tubes of the kidney?

A- Aldosterone
B- Calcitriol
C- Cortisol
D- Retinol

B- Calcitriol- It is the active form of vitamin D (1,25-dihydroxyvitamin D). It works in conjugation with PTH to facilitate absorption of calcium.
The correct answer is B

 

Question 6. A patient with a history of renal disease presents to the clinic for a follow up and renal function tests. Clearance of which one of the following substances is used to estimate the glomerular filtration rate?

A- Calcium
B- Inulin
C- Potassium
D- Sodium

B-Inulin- It is neither reabsorbed nor secreted so, it is used to estimate glomerular filtration rate. Other substances are reabsorbed and/or secreted through renal pathway.
The correct answer is B

 

Question 7. Folic acid is given to pregnant women to decrease the risk of having a fetus with a neural tube defect. This treatment is a cofactor of which one of the following processes?

A- Active electron transport
B- Biosynthesis of nucleotides
C- Glycolysis
D- Triglyceride lipolysis

B- Biosynthesis of nucleotides- Folic acid play an important role in the synthesis of DNA, methionine from homocysteine and modification of DNA and RNA.
The correct answer is B

 

Question 8. Diabetic retinopathy is most likely caused by direct damage of which one of the following locations of the eye?

A- Ciliary body
B- Choroidal plexus
C- Corneal epithelium
D- Endothelial lining of the small blood vessels

D-Endothelial lining of the small blood vessels- Diabetes affects the eye in the same way it affects all other organs such as the heart, kidney, brain, etc. Endothelial lining of small retinal vessels is damaged leading to irreversible progressive loss of vision. Other locations listed may be affected indirectly through damage of their blood supply.
The correct answer is D

 

Question 9. Which one of the following cyclic endoperoxides decreases both platelet aggregation and vascular tone?

A- Prostacyclin
B- Prostaglandin PGE1
C- Prostaglandin PGE2
D- Thromboxane

A- Prostacyclin- It is the only one on the list that decreases both platelet aggregation and vascular tone. Thromboxane increases both of them.
The correct answer is A

 

Question 10. Serum calcium levels could be falsely low in which one of the following conditions?

A- Hypertension
B- Hyperthyroidism
C- Hypoalbuminemia
D- Hypothyroidism

C- Hypoalbuminemia- Ionized calcium should be checked and calculated in cases of hypoalbuminemia to get the correct result. Hypertension and thyroid defects may affect the level of serum calcium but they will not affect the measurement of serum calcium unless they are accompanied with serum hypoalbuminemia.
The correct answer is C

 

High-yield points from this set

  • The adrenal medulla is part of the sympathetic nervous system.
  • Bilateral hippocampal lesions cause anterograde amnesia.
  • Red blood cells rely only on glycolysis (no mitochondria).
  • Inulin clearance measures GFR.

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