10 USMLE Neurology, Physiology and Endocrine Quick Review Questions with Answers (Set 2)

These 10 quick USMLE review questions test high-yield facts that show up again and again on the exam: stroke and aphasia, pupillary reflexes, sympathetic transmitters, the locus coeruleus, high altitude, cerebral aneurysms, gluconeogenesis, methemoglobinemia, renin and erythropoietin. 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 arteries is most likely affected in a case of expressive aphasia?

A- Anterior cerebral
B- Middle cerebral
C- Posterior cerebral
D- Vertebral

B- Middle cerebral
The correct answer is B

 

Question 2. A middle-aged woman presents to the clinic complaining of visual difficulty. Visual examination is normal except for one abnormal sign. When light is shone in the right eye, both pupils constrict, while if it is shone in the left eye, both pupils dilate to the normal size. Which one of the following nerves is affected in this patient?

A- Left oculomotor nerve
B- Left optic nerve
C- Right oculomotor nerve
D- Right optic nerve

B-Left optic nerve- Consensual light reflex differentiates between optic nerve injury vs oculomotor nerve injury. It is lost in optic nerve injury while it is intact in oculomotor nerve injury.
The correct answer is B

 

Question 3. Which one of the following substances is released by sympathetic postganglionic neurons that innervate renal vascular smooth muscle?

A- Acetyl choline
B- Dopamine
C- Epinephrine
D- Norepinephrine

B-Dopamine- All sympathetic postganglionic neurons release norepinephrine except neurons in the sweat glands which release acetyl choline and the neurons in renal vascular smooth muscle which release dopamine.
The correct answer is B

 

Question 4. Which one of the following structures provides the majority of noradrenergic innervation to the cerebral cortex?

A- Caudate nucleus
B- Locus coeruleus
C- Raphe nucleus
D- Substantia nigra

B- Locus coeruleus- These cells contain norepinephrine and they provide the majority of noradrenergic innervation to the forebrain.
The correct answer is B

 

Question 5. Which of the following physiological changes is expected in a person climbing a mountain at an altitude of 4500 meters?

A- Decreased 2,3-diphosphoglycerate
B- Decreased erythropoietin production
C- Decreased arterial Pco2
D- Increased renal excretion of H ion

C- Decreased arterial Pco2- Decreased barometric pressure in high altitude causes arterial hypoxia. Ventilation rate increases leading to decreased arterial Pco2 and respiratory alkalosis.
The correct answer is C

 

Question 6. Which of the following is the most common site of aneurysm in the circle of Willis and may cause aphasia and hemiparesis?

A- Anterior communicating artery
B- Middle cerebral artery
C- Ophthalmic artery
D- Posterior communicating artery

A-Anterior communicating artery- 85% of saccular brain aneurysms arise from circle of Willis. The most common location is anterior communicating artery (35%), internal carotid artery (30%) and other listed arteries (22%).
The correct answer is A

 

Question 7. High levels of which one of the following substances signal the initiation of gluconeogenesis?

A- Acetyl CoA
B- Adenosine triphosphate (ATP)
C- Citrate
D- Oxalate

A- Acetyl CoA- The primary control of gluconeogenesis is exerted by acetyl-CoA. The first step is controlled by pyruvate carboxylase which does not function in the absence of Acetyl-CoA.
The correct answer is A

 

Question 8. In a case of methemoglobinemia, which one of the following is the most likely cause of the brown color of the patient’s blood?

A- Carbon monoxide
B- Decreased oxygen affinity
C- Oxidized hemoglobin
D- Reduced hemoglobin

C- Oxidized hemoglobin- The brown color is due the oxidation of the iron in the hemoglobin to ferric state (methemoglobin).
The correct answer is C

 

Question 9. Elevation of which one of the following substances in blood occurs due to reduced renal blood flow?

A- Ammonia
B- Calcium
C- Cholesterol
D- Renin

D- Renin- It is secreted by the juxtaglomerular cells as result of reduced renal blood flow. It results in elevated blood pressure which in turn elevates renal blood flow.
The correct answer is D

 

Question 10. Secretion of which one of the following hormones is decreased due to renal failure?

A- Erythropoietin
B- Glucagon
C- Insulin
D- Thyroxin

A- Erythropoietin- It is the only hormone on the list secreted by the kidney. It stimulates erythrocyte production in the bone marrow.
The correct answer is A

 

High-yield points from this set

  • Expressive aphasia comes from a middle cerebral artery stroke (Broca area).
  • The locus coeruleus is the main source of brain norepinephrine.
  • High altitude causes hyperventilation and lower arterial PCO2.
  • Most berry aneurysms are at the anterior communicating artery.

Keep practicing

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