Special Senses II: Lecture 24

Question 1

olfaction structure

Answer 1

olfactory epithelium in the roof of the nasal cavity

Question 2

olfaction sensory neurons

Answer 2

bipolar; apical dendrite with projecting cilia gathered into fascicles

Question 3

olfaction

Answer 3

detection or odorants in air transduced into signals

Question 4

olfaction specificity

Answer 4

different 1 trillion odors
about 400 genes for smell

Question 5

olfaction physiology

Answer 5

chemicals must be volatile for olfaction, odorants dissolve in mucus and bind to receptor proteins

Question 6

olfaction pathway

Answer 6

sensory neurons synapse in the olfactory bulbs, mitral cells signal to olfactory tracts

Question 7

activation of olfactory receptors

Answer 7

odorants dissolved in mucus surrounding olfactory neuron’s cilia
odorant-binding proteins transport odorants through mucus to receptors on cilia of olfactory neuron

Question 8

olfactory transduction

Answer 8

-binding of odorant to receptor activates G-protein
-activated G-protein triggers enzyme adenylate cyclase to convert ATP into cyclic AMP (cAMP)
-cAMP opens ion channels; allow sodium and calcium ions to enter cell; causes depolarization and action potential generation if threshold is reached

Question 9

gustation structure

Answer 9

taste buds, gustatory epithelial cells, basal epithelial cells

Question 10

gustatory sense

Answer 10

chemoreceptors are stimulated by various chemicals

Question 11

gustatory process

Answer 11

process involving olfactory chemoreceptors, thermoreceptors, and nociceptors in addition to gustatory chemoreceptors

Question 12

taste buds

Answer 12

located on the lateral surfaces of papillae; contain gustatory, basal, and supporting cells

Question 13

basal cells (taste)

Answer 13

stem cells that continuously differentiate into new gustatory cells; 10-14 days lifespan

Question 14

supporting cells (taste)

Answer 14

surround and physically support gustatory cells; no role in taste sensation

Question 15

sweet tastes

Answer 15

elicited by simple sugars (glucose, fructose)

Question 16

sour tastes

Answer 16

produced by hydrogen ions

Question 17

salty tastes

Answer 17

elicited by presence of metal ions

Question 18

bitter flavors

Answer 18

produced by nitrogen-containing compounds

Question 19

umami

Answer 19

produced by glutamate or other amino acids

Question 20

gustatory physiology

Answer 20

chemical binds to receptors > graded depolarizing potential > triggers generator potentials > meets threshold for activation > rapid adaptation occurs

Question 21

taste receptors

Answer 21

classified by substance they detect; only one type of receptor associated with individual gustatory cell
substance must dissolve in saliva before it can reach taste bud and be detected

Question 22

taste pathway

Answer 22

facial, glossopharyngeal, vagus nerve to synapse in the solitary nucleus of the medulla

Question 23

smell and taste relationship

Answer 23

about 80% of taste is the result of olfaction

Question 24

auricle/pinna

Answer 24

elastic cartilage surrounding the external auditory meatus, funnels sound waves

Question 25

external auditory meatus

Answer 25

short tube from auricle to tympanic membrane ceruminous glands -> earwax

Question 26

tympanic membrane/eardrum

Answer 26

connective tissue membrane, sound waves vibrate the eardrum

Question 27

oval window

Answer 27

receives sound waves from ossicles

Question 28

epitympanic recess

Answer 28

roof of middle ear cavity

Question 29

mastoid antrum

Answer 29

allows for communication to mastoid air cells; middle ear

Question 30

pharyngotympanic/auditory tube

Answer 30

continuous with the lining of the pharynx; opens during swallowing or yawning allows for pressure equilization

Question 31

auditory ossicles

Answer 31

malleus, incus, and stapes suspended by ligaments, transmit sound waves

Question 32

ear musculature

Answer 32

tensor tympani: muscle attaches to the malleus stapedius: muscle attaches to the stapes

Question 33

bony labyrinth

Answer 33

inner ear region that channels through the bone; filled with perilymph

Question 34

vestibule

Answer 34

cavity flanks the middle ear; made of utricle and saccule, houses maculae

Question 35

semicircular canals

Answer 35

oriented in 3 different planes: anterior, posterior, lateral semicircular duct communicates with utricle ampulla: swelling at one end

Question 36

membranous labyrinth

Answer 36

membranous sacs and ducts in the inner ear; surrounded by perilymph, filled with endolymph aid in conduction of sound waves

Question 37

cochlea

Answer 37

spiral shaped chamber that extends from the vestibule; contains helicotrema, cochlear duct (spiral organ), and osseous spiral lamina

Question 38

scala vestibuli

Answer 38

continuous with vestibule, begins at oval window, filled with perilymph

Question 39

scala media

Answer 39

cochlear duct, filled with endolymph

Question 40

scala tympani

Answer 40

terminates at round window, filled with perilymph

Question 41

basilar membrane

Answer 41

thick near oval window, widens and flattens near cochlea apex hair reside on top

Question 42

hair cells

Answer 42

inner and outer hair cells innervated by cochlear nerve- division of vestibulocochlear nerve

Question 43

sound transmission

Answer 43

sound waves funneled into auditory canal, strike tympanic membrane vibration transferred to ossicles to oval window oval window generates waves in fluid of inner ear

Question 44

frequency

Answer 44

number of waves in a given time; determines pitch

Question 45

amplitude

Answer 45

height of the sound wave; determines intensity/loudness hearing loss at 90+ decibels

Question 46

pitch

Answer 46

(Hz) determined by which area of the basilar membrane vibrates

Question 47

loudness

Answer 47

(dB) determined by how much basilar membrane vibrates at same area

Question 48

stereocilia

Answer 48

microvilli on hair cells; flex at their junction with hair cell body to detect cells

Question 49

tectorial membrane

Answer 49

stiff structure that extends over hair cells; sandwiches cells and their stereocilia between tectorial membrane and basilar membrane

Question 50

sound transmission to inner ear

Answer 50

-basilar membrane moves up toward tectorial membrane, bending stereocilia toward tallest stereocilium -bending stereocilia opens potassium ion channels, depolarize hair cells -depolarized hair cells release neurotransmitter, triggering action potentials

Question 51

vestibular apparatus

Answer 51

semicircular canals and vestibule that contain equilibrium receptors

Question 52

maculae

Answer 52

sensory receptor organs; one in each saccule that evaluate head position and acceleration

Question 53

maculae structure

Answer 53

hairs cells and otoliths utricle: vertical hair cells saccule: horizontal hair cells

Question 54

balance innervation

Answer 54

synapse with the vestibular nerve reflex- vestibular nystagmus: eyes drift toward opposite direction of movement

Question 55

balance signal transduction

Answer 55

otoliths respond to gravity and movement hair cells release neurotransmitter constantly

Question 56

cristae ampullaris

Answer 56

receptor for rotational acceleration

Question 57

balance pathway

Answer 57

impulses travel to the vestibular nuclei in the brain stem or the cerebellum