Examination of Smell, Taste, and Hearing

Question 1

Where is the olfactory epithelium located at the mucous membrane lining of the nasal cavity?

Answer 1

Inferior portion of the cribriform plate at the ethmoidal plate

Question 2

What cells are responsible for olfaction?

Answer 2

Bipolar sensory cells

Question 3

What is the main relay station for olfaction?

Answer 3

Olfactory bulb

Question 4

What are the 3 olfactory striae (axons of olfactory bulb)? Which of these striae is the most important for smelling bcos this is where smells are pereceived?

Answer 4

Lateral olfactory striae - most important
Intermediate olfactory striae
Medial olfactory striae

Question 5

What CN can be stimulated if u use alcohol or perfume for CN exam?

Answer 5

CN V1 - opthalmic division of the trigeminal nerve

Question 6

What are the 4 conditions that can affect CN I?

Answer 6

1. Fractures of cribriform plate of ethmoid bone
2. Hemorrhage at base of frontal lobes
3. Meningitis or abscess of frontal lobe
4. Hypophyseal tumors

Question 7

What condition is noted in px with olfactory groove or sphenoid ridge masses (meningiomas) or space occupying lesions of the frontal lobe?

Answer 7

Foster-Kennedy syndrome

Question 8

What condition is noted in px w/ olfactory groove or sphenoid ridge masses (menangiomas) or space in the lesions of the frontal lobe?

Answer 8

Foster-Kennedy syndrome

Question 9

What are the clinical presentation of Foster-Kennedy syndrome?

Answer 9

Ipsilateral anosmia
Ipsilateral optic atrophy
CL papilledema -> affected visual pathway

Question 10

What CN I disorder is caused by a rare mutation that presents with congenital anosmia and hypogonadotropic hypogonadism?

Answer 10

Kallman syndorme

Question 11

What gene is affected/mutated in Kallman syndrome?

Answer 11

KAL 1 gene

Question 12

What are the imaging findings seen in Kallman syndrome?

Answer 12

Complete agenesis of the olfactory bulbs and sulci, OR medial orientation of the sulfatory sulci

Question 13

What are the causes of Anosmia in COVID-19?

Answer 13

1. Direct affectation of the virus through the Transmural pathway
2. Hematogenous spread: breaking through the BBB

Question 14

WHere are taste cells located?

Answer 14

Within the tongue epithelium

Question 15

What is the innervation of the Anterior 2/3 of the tongue?

Answer 15

Chorda tympani (branch of CN VII)

Question 16

What is the innervation of the posterior 1/3 of the tongue?

Answer 16

Afferents of the petrosal ganglion: CN IX

Question 17

What innervates the epiglottis and larynx?

Answer 17

SUperior laryngeal nerve

Question 18

Explain the GUstatory pathway?

Answer 18

Afferent tracts enter the brainstem —> synapses with ROSTRAL NUCLEUS OF THE SOLITARY TRACT —> gives afferent fibers to the IPSILATERAL pontine taste area as the CENTRAL TEGMENTAL TRACT —> IL Ventral-posteromedial nucleus of the thalamus —> IL primary gustatory area —> L hypothalamus & amygdala —> emotions with diff tastes

Question 19

What are the objects used in examination of Gustation?

Answer 19

Sugar & salt soln
Disposable cotton applicator
Sterile gauze
H2O for drinking and gargling

Question 20

What are the main indicators of localization for gustatory pathway?

Answer 20

Loss of appetite, smell, or taste
Bell’s palsy or idiopathic peripheral facial palsy

Question 21

What CN is usually affected by UL loss of taste & at what side?

Answer 21

Ipsilateral CN VII

Question 22

What is the medical torm for loss of taste due to affectation of taste buds?

Answer 22

Ageusia

Question 23

Why is the sense of taste affected by COVID 19?

Answer 23

Virus binds to sialic acid receptors (taste bud) —> inflam & edema -> degradation & apoptiosis of taste receptors —> reduced salivary flow

Question 24

What are the structures of the external/outer ear?

Answer 24

Pinna/Auricule
External auditory canal
Tympanic membrane

Question 25

Where is the middle ear/tympanic cavity located?

Answer 25

within the temporal bone

Question 26

What structure in the middle ear separates the middle and inner ear?

Answer 26

Oval and round windows

Question 27

What are the parts of the bony ossicles?

Answer 27

Malleus Stapes Incus

Question 28

What are the muscles found in the middle ear/tympanic cavity?

Answer 28

Tensor tympani Stapedius

Question 29

Where is the inner ear found?

Answer 29

Petrous portion of the temporal bone

Question 30

What are the 2 systems of canal in the inner ear/

Answer 30

Osseus/bony labryinth Membranous labyrinth

Question 31

In the perilymph found in the Osseus/bony labyrinth, what cation is found in high concentraiton?

Answer 31

Na+

Question 32

In the endolymph found in the Membranous labyrinth, what cation is found in high concentration?

Answer 32

K+

Question 33

What are the 2 cavities of the membranous labyrinth?

Answer 33

Utricle - posterior with semicircular canal Saccule - anterior with cochlea

Question 34

What are the sensory areas of the membranous labyrinth and what part of the inner membrane are they located?

Answer 34

Maccule utriculi - L wall of the utricle Maccule sacculi - floor of the saccule

Question 35

What is the Organ of corti composed of?

Answer 35

Hair cells + Supporting cells

Question 36

What are the main sensory/auditory receptors of the ear?

Answer 36

Hair cells

Question 36

What are the main sensory/auditory receptors of the ear?

Answer 36

Hair cells

Question 37

What stimulates hair cells near the oval window & hair cells near the apex of the cochlea?

Answer 37

Hair cells near apex of the cochlea -> LOWER frequencies/tone Hair cells near oval window -> HIGHER frequencies/tone

Question 38

What is the first order neuron in the auditory pathway?

Answer 38

neurons of spiral ganglion

Question 39

What are the second order neuron in the auditory pathway?

Answer 39

Cochlear nuclei

Question 40

in the cochlear nuclei, what structure receives fibers that innervate HIGH FREQUENCY basal hair cells?

Answer 40

Dorsal Cochlear nucleus

Question 41

in the cochlear nuclei, what structure receives fibers that innervate LOW FREQUENCY basal hair cells?

Answer 41

Ventral cochlear nucleus

Question 42

What are the structures found in the central nucleus of the inferior colliculus?

Answer 42

1. Dorsal acoustic striae -> from DORSAL COCHLEAR NUCLEUS 2. Intermediate acoustic striae -> from DORSAL PART OF VENTRAL COCHLEAR= NUCLEUS 3. Ventral acoustic striae -> from the VENTRAL COCHLEAR NUCLEUS

Question 43

Where does the ventrial acoustic striae terminate?

Answer 43

IL & CL reticular formation, superior olivary nuclei, and nuclei of the trapezoid body

Question 44

Where are the third order neurons found?

Answer 44

Inferior colliculus

Question 45

Where in the medial geniculate body of the thalamus can LOW.& HIGH freq fibers end up?

Answer 45

Apical & L areas = LOW FREQ fibers Middle portion of the nuclear mass = HIGH FREQ fibers

Question 46

Where are the fourth order neurons found?

Answer 46

Medial geniculate nucleus

Question 47

What cortex does the fourth order neuron project to?

Answer 47

primary auditory cortex (BA 41, 42) in the superior temporal gyrus

Question 48

In the primary auditory cortex, where do high & low frequencies terminate?

Answer 48

Medially = HIGH freq Laterally = LOW freq

Question 49

How do you diagnose if it is a Conductive hearing loss?

Answer 49

Weber test = Lateralizes to the ABNORMAL ear Rinne test = Bone conduction > Air conduction

Question 50

What part of the ear is affected in Conductive hearing loss?

Answer 50

conduction of sound waves in the middle ear

Question 51

What causes Conductive hearing loss?

Answer 51

impacted cerumen chronic otitis media otosclerosis

Question 52

How do you diagnose Sensorineural hearing loss?

Answer 52

Weber test = lateralizes to the NORMAL side Rinne test = AC > BC

Question 53

Where is the problem in sensorineural hearing loss?

Answer 53

inner ear = Organ of corti, CN VIII, cochlear neuclei of the pons, central auditory pathway

Question 54

What are the causes of sensorineural hearing loss?

Answer 54

any central cause for the hearing loss