BCN Back of book Questions Quiz 3

Question 1

What are the 3 tactile mechanoreceptors, and which is most sensitive? Ch 11

Answer 1

Meissneir corpuscle
Merkle Discs (smallest receptive field = most sensitive)
Hair Follicle

Question 2

How is intensity of a cutaneous stimulus transmitted from the receptor into the CNS? Ch 11

Answer 2

by the number and frequency of action potentials conducted in the sensory afferent axons.

Question 3

What is sensory adaptation? Ch 11

Answer 3

Occurs when a temporally protracted and constant sensory stimulus results in gradual diminution of the receptor potential

Question 4

What is the functional importance of surround inhibition in the transmission of somatosensory information? Ch 11

Answer 4

This maintains the resolution of somatosensory transmission by blocking the relay of a sensation from neurons coactivated by stimulation to adjacent sensory fields.

Question 5

How do fast and slow pain pathways differ in the forebrain? Ch 11

Answer 5

Fast is more lateral thalamus

Slow is more medial

Question 6

Where would the general somatic sensory loss be if you ruptured the disc into the left intervertebral foramen between LV5 and SV1? Ch 11

Answer 6

Cutaneous touch and pain sensations in dermatone L5 (first 4 toes and the dorsum of the foot)

Question 7

Where would the general somatic sensory loss be if you had a left hemisection of spinal cord at T10? Ch 11

Answer 7

Tactile, vibration, and proprioception senses below umbilicus on left side.
Pain and temperature sensations below inguinal ligament on the right side

Question 8

Where would the general somatic sensory loss be if the ventral white commissure from T2 to T4 is damaged? Ch 11

Answer 8

Pain and temp sensations bilaterally at nipple level (this is where spinalthalamic tract decussates)

Question 9

Where would the general somatic sensory loss be if lateral 3rd of medulla at the obex (caudal medulla)? Ch 11

Answer 9

Pain in the face on the left side and

Pinprick and temp in the occiput, neck, trunk, and limbs on the right

Question 10

Where would the general somatic sensory loss be if right medial 3rd of medulla near the pontomedullary junction? Ch 11

Answer 10

tactile, proprioception in occiput, neck, trunk, and limbs on left
pinprick in face on left side

Question 11

Where would the general somatic sensory loss be if the left ventral posterior nucleus? Ch 11

Answer 11

tactile, proprioception, pinprick, and temp on entire right side

Question 12

A patient has a demyelinating disease for a number of years. Among the patient’s deficits is a loss of one of the pain modalities. Which of the following sensations would be predicted to be reduced due to the underlying demyelinating disease? Ch11

Answer 12

Sharp pain associated with a laceration (Sharp pain fibers are myelinated)

Question 13

A patient has a vascular lesion of the thalamic ventral posterolateral nucleus. This lesion will result in loss of? Ch11

Answer 13

Tactile localization in the contralateral body (hand).

Question 14

A patient with a loss of tactile and pain sensations on the left side of the face may have a lesion of the? Ch 11

Answer 14

Right ventral posteromedial nucleus

Question 15

A patient with intolerable pain undergoes a cervical anterolateral cordotomy. While anterograde (Wallerian) axonal degeneration would be expected to be observed in numerous brain structures, the one location where you would not look for degenerating axons would be in the? Ch 11

Answer 15

Postcentral gyrus

Question 16

Bending of the stereocilia as a result of vibration of the basilar membrane toward the scala vestibuli results in what physiologic response? Ch 12

Answer 16

Influx of potassium from the endolymph in the cochlear duct, resulting in depolarization of the hair cells and the activation of primary auditory afferent axons

Question 17

Frequency (tone) and intensity (loudness) of an auditory stimulus is primarily signaled in what receptor cells? Ch 12

Answer 17

Inner hair cells

Question 18

Account for the bilateral representation of sound in the auditory system. Ch 12

Answer 18

Bilateral connections of:

1. Superior olivary and trapezoid nuclei
2. nuclei of the lateral lemniscus
3. inferior colliculi

Question 19

As an acoustic neurinoma on the vestibular nerve in the internal acoustic meatus expands, what other nerves become impaired? Ch 12

1. In the internal acoustic meatus
2. In or near the cerebellar angle

Answer 19

1. Cochlear and facial

2. Trigeminal, hypoglossal, and possibly abducens and vagus

Question 20

Contrast conduction deafness and neural deafness? Ch 12

Answer 20

Conduction deafness: external or middle ear disease, injuries that cause interference with conduction of sound waves or vibrations of tympanic membrane or ossicles.
Nerve deafness: injury or disease to spiral organ, or cochlear nerve.

Question 21

Where in the auditory system does a unilateral lesion produce total deafness in the ipsilateral ear? Ch 12

Answer 21

Spiral organ
Spiral ganglion
Cochlear nerve
Dorsal or ventral cochlear nuclei

Question 22

Conduction deafness must result from damage to?? Ch 12

Answer 22

incus (any of the ossicles or tympanic membrane)

Question 23

A patient with the inability to recognize the source of sounds may be expected to have damage to what nuclei? Ch 12

Answer 23

Superior olivary

Question 24

A patient can hear louder in right ear with Weber test. With Rinne test the patient hears the fork much louder and longer on the left, but when the tuning fork is placed on the right mastoid the sound is heard. What’s the deal with this guy? Ch 12

Answer 24

Conduction deafness on the right side

Question 25

Describe the pathway that causes extension of the left limbs on falling toward the left. Ch 13

Answer 25

Impulses from the maculae of the utricles and saccules go through the vestibular ganglion and nerve to vestibular nuclei.
From left lateral vestibular nucleus, impulses descend to lower motor neurons (left lateral vestibulospinal tract) to facilitate extensor muscles of the left limbs

Question 26

Name which structures of the internal ear are chiefly associated with: Ch 13
Equilibrium:
Visual fixation:

Answer 26

Equilibrium: Maculae of utricle and saccule
Visual Fixation: Cupulae of the ampullary crests in the semicircular ducts shift on rotation of the head, thereby initiating the vestibulo-ocular reflex.

Question 27

What is the anatomic basis for the slow phase of rotary and caloric nystagmus? Ch 13

Answer 27

The vestibulo-ocular reflex

Question 28

Assuming an intact vestibulo-ocular reflex path, what response occurs on cold water irrigation of the right external auditory meatus in a patient who is: Ch 13
Conscious:
Comatose:

Answer 28

Conscious: left nystagmus (COWS) that is fast phase
Comatose: turning of eyes to same side as long as irrigation is continued. There is no fast phase in comatose state.

Question 29

Where is the lesion when cold water irrigation in left ear in a comatose patient results in both eyes looking lateral? Ch 13

Answer 29

VOR is interrupted in the central brainstem somewhere between the levels of the vestibular and oculomotor nuclei (midpons to rostral mid-brain)

Question 30

In the examination room, a patient when lying down with eyes closed complains of a sense that the head is rotating. If the lesion is in the inner ear the most likely source of for the abnormal impulse would arise from where? Ch 13

Answer 30

Semicircular ducts (patients head is still and eyes are closed)

Question 31

A 67-year-old man complains of recurring 2 to 4 hour attacks of vertigo accompanied by severe nausea and vomiting, tinnitus and a sensation of fullness in the middle ear. These debilitating bouts occur even when the head is not moving and with the eyes open or closed. A likely diagnosis is? Ch 13

Answer 31

Meniere disease (this is disease that can cause vertigo that comes and goes and has a build up of fluid in the ear)

Question 32

A 22-year-old woman, while replacing a light bulb, falls 6 feet from a ladder and bumps her head on the floor. Twenty-four hours later she complains of spells of dizziness with sudden onset and duration of about 30 seconds. The abnormal sensations are especially severe when sitting up, rolling over in bed, or putting her head between her legs. The most likely cause of sudden onsets of dizziness is: ch 13

Answer 32

Displaced otoliths (BPPV)

Question 33

A 30 year-old man sustains multiple fractures in an auto accident. When hospitalized he is treated with IV gentamicin for an open femur fracture. Several days later he complains of severe vertigo and oscillopsia. He has normal hearing in both ears. The most likely cause for vertigo is: Ch 13

Answer 33

Gentamicin Ototoxicity

Question 34

A patient with advanced DM and peripheral neuropathy becomes progressively more clumsy when getting out of bed during the night and walking in the dark. During the day or in a lighted room movements appear normal. A romberg sign is present. What would account for the ataxia? Ch 13

Answer 34

Damage to vestibular system (positive romberg helps tell that vision is ok, the dark room is like romberg) He already has decrease in proprioception due to diabetes. Increased deficiency in balance can be due to damage to vestibular system