Week 12 - Special Senses

Question 1

List the three compartments of the ear

Answer 1

external ear, middle ear, internal ear

Question 2

List the structures of the external ear

Answer 2

Auricle (helix, lobule), external auditory canal, tympanic membrane

Question 3

List the structures of the middle ear

Answer 3

auditory ossicles - malleus, incus, stapes in oval window

oval & round windows of the labyrinth, stapedius muscle, tensor tympani muscle

Question 4

The stapedius muscle is innervated by ______

Answer 4

CN V - mandibular branch

Question 5

The tensor tympani muscle is innervated by _______

Answer 5

CN VII

Question 6

List the structures of the inner ear

Answer 6

labyrinth: bony/outer labyrinth, membranous/inner labyrinth

Question 7

The bony labyrinth is lined with _______. There is ______ flowing in between bony and membranous labyrinth. Within the membranous labyrinth there is ________

Answer 7

periosteum
perilymph
endolymph

Question 8

The stapes of the middle ear fits into what window of the labyrinth?

Answer 8

oval

Question 9

List parts of the labyrinth and their functions

Answer 9

semicircular canals - rotational equilibrium
vestibule (sacculi, utricle) - straight-forward equilibrium
cochlea - hearing

Question 10

The Organ of Corti is located in the ______ and represents __________

Answer 10

cochlea

receptors for hearing

Question 11

The hearing receptors in the Organ of Corti are called ______. They are bathed in _____ and covered by _____

Answer 11

hair cells
endolymph
tectorial membrane

Question 12

Describe the auditory pathway of first order sensory neurons

Answer 12

spiral ganglion -> cochlear branch of CN VIII -> cochlear nuclei of medulla oblongata (same side) and superior olivary nuclei in the pons (both sides)

Question 13

The second order sensory neurons of the auditory pathway include _______

Answer 13

inferior coliculi in the midbrain

Question 14

The third order sensory neurons of the auditory pathway include _______

Answer 14

medial geniculate body of the thalamus

Question 15

In the auditory pathway, third order sensory neurons transmit impulses to __________

Answer 15

primary cortical area in the superior temporal gyrus (41, 42)

Question 16

Describe the equilibrium pathway

Answer 16

Sensory receptors (hair cells) -> vestibular neuron bodies in vestibular ganglia -> vestibular axons of CN VIII -> vestibular nuclei of the medulla and pons -> cerebrum and cerebellum

Question 17

The lateral/temporal retina absorbs light from the ______ panorama.

Answer 17

medial

Question 18

The medial/nasal retina absorbs light from the _______ panorama.

Answer 18

lateral

Question 19

The fibers of the optic nerve that originate from ganglion cells in the nasal half of the retina decussate in the _________ to the opposite optic tract.

Answer 19

optic chiasm

Question 20

Each optic tract has within it axons representing the ______ of the visual field

Answer 20

contralateral half

Question 21

Ménière’s disease is __________

Answer 21

a condition where endolymph swells the membranous labyrinth and nearby areas causing hearing and balance difficulty (tinnitus, vertigo, dizziness)