Download (direct link):
-has a pitch localization along its length: 20 Hz at the apex and 20,000
Hz at the base of the cochlea, -vibration results in deformation of the
hair cell microvilli against the
tectorial membrane; this action serves as the adequate stimulus.
6. Spiral ganglion (of CN VIII)
-is located in the bony modiolus of the cochlea.
—consists of bipolar neurons of the cochlear division of the vestibulo-
cochlear nerve (CN VIII).
III. Auditory Pathway (see Figure ii-i)
-is characterized by reciprocal connections throughout its caudorostral extent
and by multiple decussations at all levels,
-consists of the following structures:
A, Hair cells of the organ of Corti
-are innervated by peripheral processes of bipolar cells of the spiral gan-
18 / Neuroanatomy
9. The mesencephalon includes all of the fol 11. All of the following statements concern
lowing structures EXCEPT the ing the cerebellum are correct EXCEPT it
(A) cerebral peduncle (A) is found in the posterior cranial fossa
(B) cerebral aqueduct (B) is part of the brainstem
(C) inferior colliculus (C) is separated from the occipital lobes by
(D) pineal body the tentorium cerebelli
(E) oculomotor nerve (D) has three lobes
10. The frontal lobe includes all of the follow (E) has a tonsil
ing areas EXCEPT 12. The parietal lobe contains all of the fol
(A) Wernicke's speech area lowing structures EXCEPT the
(B) the motor strip (area 4) (A) angular gyrus
(C) the precentral gyrus (B) sensory strip (areas 3, 1, and 2)
(D) Broca's speech area (C) supramarginal gyrus
(E) the center controlling eye movements (D) primary auditory cortex
180 / Neuroanatomy
—consist of two types:
1. Inner hair cells
-synapse with numerous afferent fibers, each of which makes contact
with only one hair cell; the majority of fibers in the cochlear nerve
come from the inner hair cells.
2. Outer hair cells
-synapse with afferent fibers that contact numerous other outer hair
cells, -outnumber the inner hair cells three
B. Bipolar cells of the spiral (cochlear) ganglion
-project peripherally to hair cells of the organ of Corti. -project centrally
as the cochlear nerve to the dorsal and ventral cochlear nuclei of
the medullopontine junction.
C. Cochlear nerve (CN VIII) [see Figures 1-1, 9-5, and 11-1]
—extends from the spiral ganglion to the cerebellopontine angle, where it
enters the brainstem.