Week 7: Auditory, Vestibular, Olfaction, and Taste

Question 1

Membranous Labyrinth Contents

Answer 1

Endolymph

Question 2

Endolymph Composition

Answer 2

High in K+, Low in Na+

Question 3

Bony Labyrinth Contents

Answer 3

Perilymph

Question 4

Perilymph Composition

Answer 4

Resembles extracellular fluid and CSF

Question 5

Relationship of Membranous Labyrinth to Bony Labyrinth

Answer 5

Membranous labyrinth is suspended in the boney labyrinth

Question 6

Action of Tectorial Membrane to Organ of Corti

Answer 6

Organ of corti moves in response to sound pressure, which causes its hair cells to brush against the tectorial membrane

Question 7

Inner Hair Cell Anatomy

Answer 7

Single row innervated by up to 10 nerve fibers

Question 7

Inner Hair Cell Function

Answer 7

Detection of frequency and fine discrimination of sounds

Question 8

Outer Hair Cell Anatomy

Answer 8

3 to 4 rows but 1 nerve fiber for multiple cells

Question 8

Outer Hair Cell Function

Answer 8

Efferent structures that modulate sensitivity of the organ of Corti by changing length in response to sound

Question 9

Cochlear Frequency Organization

Answer 9

High to low down the length and spiral of the cochlea

Question 10

Superior Olivary Nuclear Complex Function

Answer 10

Localizing sound in space

Question 11

Location of Decussating Auditory Fibers

Answer 11

Trapezoid Body of Caudal Pons or Pontine Tegmentum

Question 12

Blood Supply of Cochlear Nuclei

Answer 12

Anterior Inferior Cerebellar Artery

Question 13

Primary Auditory Cortex Location

Answer 13

Anterior transverse gyrus of temporal lobe medial to superior temporal gyrus and viewed by opening the lateral fissure

Question 14

Secondary and Higher Order Auditory Cortex Location

Answer 14

Belt around the primary cortex

Question 15

Secondary and Higher Order Auditory Cortex Function

Answer 15

Activated by complex sounds

Question 16

Vestibular System Gross Anatomy

Answer 16

Utricle, Saccule, 3 Semicircular canals

Question 17

Utricle and Saccule Function

Answer 17

Linear acceleration and gravitational positioning

Question 18

Semicircular Canals Function

Answer 18

Angular acceleration

Question 19

Macula of Utricle and Saccule

Answer 19

patch of hair cells in each organ covered by otolithic membrane

Question 20

Otolithic Membrane

Answer 20

Gelatinous patch covered by otoliths

Question 21

Cupula of Semicircular Canals

Answer 21

Movement of endolymph against this structure causes hair cells within it to bend, which senses motion

Question 22

Vestibular Pathways

Answer 22

1. Medial Longitudinal Fasciculus
2. Vestibulospinal Tract
3. Vestibulocolic Pathways
4. Vestibulothalamocortical
5. Vestibulocerebellar
6. Vestibuloreticular

Question 23

Medial Longitudinal Fasciculus Vestibular Function

Answer 23

Bilateral connections with CN II, IV, VI, and superior colliculus, influencing eye movement

Question 24

Vestibulospinal Tract Vestibular Function

Answer 24

Medial and lateral tracts to influence posture

Question 25

Vestibulocolic Pathways Vestibular Function

Answer 25

CN XI nucleus, influencing head position

Question 26

Vestibulothalamocortical Vestibular Function

Answer 26

Conscious awareness of head movements and positions, and input to corticospinal tract

Question 27

Vestibulocerebellar Vestibular Function

Answer 27

Controls magnitude of muscle responses to vestibular information

Question 28

Vestibuloreticular Vestibular Function

Answer 28

Influences autonomic centers for nausea and vomiting

Question 29

Taste Nucleus

Answer 29

Rostral solitary nucleus