Exam IV-Auditory

Question 1

What type of fluid FILLS the membraneous labyrinth? What type of fluid is between the bony and membranous labyrinth?

Answer 1

Endolymph fillls, perilymph between

Question 2

How many turns for the Cochlea?

Answer 2

2.5

Question 3

What is the point where the Scala Tympani and the Scala Vestibuli meet?

Answer 3

HelicoTrema

Question 4

Which Scala is Superior? Which is Inferior?

Answer 4

SUPERIOR=Scala Vestibuli INFERIOR=Scala Tympani

Question 5

Which structure houses the endolymph?

Answer 5

The Scala Media

Question 6

Which structure contains the perilymph?

Answer 6

Both the Scala Vestibuli and the Scala Tympani

Question 7

Where are the hair cells contained?

Answer 7

The Organ of Corti

Question 8

What type of channels open when the stereocillia move? What is created?

Answer 8

Ion channels open in the hair cells, creating a receptor potential

Question 9

What is released once the receptor potential is large enough?

Answer 9

A nerotransmitter is released causing VIII to depolarize

Question 10

How many outer cells are in the organ of Corti? Inner?

Answer 10

3 outer cells, 1 inner

Question 11

Which hair cell is large and round? Inner or outer?

Answer 11

Inner cells are larger and rounder. Outercells are small and thin

Question 12

Which part of the cochlea senses HIGH pitch?

Answer 12

The base of the cochlea, so the Apex senses Low pitch

Question 13

What is the central hearing pathway? What does each mean?

Answer 13

8-C-SLIMA 8:CN VIII….C:Cochlear Nucleus…S:Superior Olivary Nucleus….L:Lateral Lemniscus….I:Inferior Colliculus….M:Medial Geniculate Nucleus….A:Auditory Cortex

Question 14

Where is the cochlear nucleus?

Answer 14

the medulla

Question 15

what percentage of axons of the cochlear nuclei decussate in the lower pons?

Answer 15

80%

Question 16

How do the neurons get from the medial geniculate to the primary auditory cortex?

Answer 16

The internal capsule

Question 17

What is the hearing gyrus in the primary auditory cortex? What brodmann numbers?

Answer 17

Transverse gyri of Heschel, brodmanns 41 and 42

Question 18

Where does the pathway split to orient eyes and head toward a sound?

Answer 18

At the inferior colliculus->to the superior colliculus

Question 19

Where does the pathway split to wake you up with loud noises?

Answer 19

From the Cochlear Nuclei to the RETICULAR formation!

Question 20

What pathway INHIBITS extra noise?

Answer 20

Descending pathway/centrfugal Pathway

Question 21

How does the descending /centrifugal pathway reach the cochlea?

Answer 21

The internal auditory canal

Question 22

What ossicle does the tensor tympani insert into? What CN innervates it?

Answer 22

Malleus, V

Question 23

What innervates the stapedeus muscle?

Answer 23

VII

Question 24

What is mechanical interruption of hearing? What are three examples?

Answer 24

Conductive Deafness: Obsrtuction, OtoSclerosis, Otitis Media

Question 25

What causes Sensorineural Deafness?

Answer 25

disease of the nerves VIII or pathways…Toxins, drugs, infection

Question 26

What is Meniere’s Disease?

Answer 26

Overproduction of endolymph/can’t absorb it

Question 27

Would a lesion to 8CSLIMA cause total deafness?

Answer 27

Nope, c/o decussation at the lower pons