ATI LPN
Medical-Surgical Nursing Neurological System Questions
Question 1 of 5
A physiology experiment is conducted in which a glass microelectrode in inserted into a Pacinian corpuscle to record receptor potentials during different levels of stimulation (from 0 percent to 100 percent). Increasing stimulus strength from 10 percent of maximum to 30 percent of maximum causes a 40 percent increase in the amplitude of the receptor potential. Increasing the stimulus potential from 70 percent of maximum to 90 percent of maximum is most likely to cause which increase in the amplitude of the receptor potential (in percent)?
Correct Answer: A
Rationale: Pacinian corpuscles show greater receptor potential increases at lower stimulus strengths; at higher strengths (70-90%), the increase is smaller (10%). TMP13 pp. 597-598
Question 2 of 5
Which somatosensory deficit is NOT typically seen after the development of lesions that involve the postcentral gyrus?
Correct Answer: D
Rationale: Postcentral gyrus lesions impair sensation, not motor function (precentral gyrus). TMP13 p. 613
Question 3 of 5
A 10-year-old boy looks at ants through a magnifying glass. He finds that the ants must be 10 centimeters from the convex lens to be in focus. Which value best describes the refractive power of the lens (in diopters)?
Correct Answer: C
Rationale: Refractive power = 1 / focal length (in meters). Focal length = 10 cm = 0.1 m, so 1 / 0.1 = 10 diopters. TMP13 pp. 637-638
Question 4 of 5
A 60-year-old woman visits the ophthalmologist because of eye pain. Tests show that her right eye has an intraocular pressure of 22 mm Hg and her left eye has an intraocular pressure of 25 mm Hg. Which of the following is the most likely cause of eye pain in this woman?
Correct Answer: C
Rationale: Open-angle glaucoma, with increased trabecular meshwork resistance, raises intraocular pressure, causing pain. TMP13 p. 646
Question 5 of 5
Which of the following best describes when the transmission of sound waves in the cochlea occurs?
Correct Answer: A
Rationale: Sound transmission occurs when the stapes pushes the oval window, displacing fluid and bulging the round window. TMP13 p. 673