USMLE Step 1 – Question of the Week #4

A 40-year-old female patient presents with soft nodules on the volar aspect of her fourth and fifth fingertips. The nodules are painful on flexion and interfere with her day to day work. She recounts being bitten by a stray dog, about one year back, on these same fingertips. At that time, she was treated with painkillers, anti-rabies injection and antibiotics. The wound had healed well and there were no complaints until recently. On examination, there is a soft fleshy mass about 1.0 cm in diameter on the volar aspect of both the fourth and fifth fingertips. The mass was surgically excised and was histologically found to be a neuroma of a peripheral sensory receptor.

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Which of these receptors is most likely involved?

A. Merkel cells

B. Muscle spindles

C. Meissner corpuscles

D. Free nerve endings

E. Pacinian corpuscles

USMLE Step 1 – Question of the Week #3

A 25-year- old healthy male participated in a running competition. After finishing running, his heart rate was 140/minute, blood pressure was 136/90 mm Hg, and respiratory rate was 20/minute. Also, he had perspired significantly.

Which of the following changes in renal hemodynamics is not expected due to activation of sympathetic nervous system?

A. Decreased renal plasma flow

B. Decreased hydrostatic pressure in glomerular capillaries

C. Decreased glomerular filtration rate

D. Decreased filtration fraction
E. Decreased hydrostatic pressure in peritubular capillaries