Physiology

Question 1

what does frequency dictate

Answer 1

pitch

Question 2

what does amplitude dictate

Answer 2

intensity

Question 3

list the functions of the external, middle and inner ear

Answer 3

external - receives sound
middle - amplifies sound by moving fluid
internal - converts sound into neurological impulse

Question 4

what are the two windows in the inner ear and their function

Answer 4

oval and round windows

permit transmission of pressure wave in enclosed canal and vibration of basilar membrane

Question 5

where is the eustachian tube connected to

Answer 5

connects the middle ear to the nasopharynx

Question 6

what is the function of the eustachian tube

Answer 6

ventilation pathway for middle ear mucosa

Question 7

name the two otolith organs and their function

Answer 7

utricle and saccule

have sensors for balance, coordination and direction of movement

Question 8

what is the vestibulo-ocular reflex

Answer 8

deflection causes by movement of the perilymph and bending causes stereocilia to deflect – tells the eye to stay fixed on an object even although the body is moving

Question 9

describe nystagmus

Answer 9

fast involuntary movements of the eye

Question 10

what type of receptors are taste and smell receptors

Answer 10

chemoreceptors

Question 11

where are the taste receptors located

Answer 11

taste buds - organs of taste

Question 12

where in the body are the taste buds found

Answer 12

on papillae of the tongue

Question 13

name the 4 types of papillae and which one lacks taste buds

Answer 13

filiform - lacks taste buds
fungiform
vallate
folliate

Question 14

describe the chemical mechanism of taste

Answer 14

taste changes ionic channels and depolarises receptor potential - initiates action potential in afferent nerves which synapse with r cells - signals conveyed to brainstem then cortical gustatory areas

Question 15

which CN supplies afferent taste fibres to brainstem from anterior 2/3rds of tongue

Answer 15

CN VII - via chorda tympani branch of facial nerve

Question 16

which CN supplies afferent taste fibres to brainstem from posterior 1/3 of tongue

Answer 16

CN IX - glossopharyngeal nerve

Question 17

which CN supplies afferent taste fibres to brainstem from epiglottis and pharynx

Answer 17

CN X - vagus nerve

Question 18

list the 5 primary tastes and what molecules they contain

Answer 18

bitter - alkaloids and toxic plant derivatives
sour - acids containing free hydrogen ions
salty - chemical salts eg NaCl
sweet - glucose configuration
umami - meaty, amino acids such as glutamate

Question 19

what is ageusia and what causes it

Answer 19

loss of taste function

caused by nerve damage, local inflammation eg glossitis and radiation

Question 20

what is hypogeusia and what causes it

Answer 20

reduced taste function

some medications or chemotherapy

Question 21

what is dysgeusia

Answer 21

distorted taste function

caused by medications, chemotherapy, neoplasms and infection

Question 22

what is olfaction

Answer 22

sense of smell

Question 23

where is the olfactory mucosa located

Answer 23

in the dorsal roof of the nasal cavity

Question 24

what 3 types of cells are found in olfactory mucosa

Answer 24

olfactory cells
supporting cells
basal cells - secrete mucus and precursors for new olfactory receptor cells

Question 25

what is the lifespan of taste buds

Answer 25

10 days

Question 26

what is the lifespan of olfactory cells

Answer 26

2 months

Question 27

describe how smell travels to the brain

Answer 27

axons of olfactory receptors form afferent fibres of olfactory nerve - these fibres pierce the cribiform plate of ethmoid bone - enter the olfactory bulbs located on inferior surface of the brain - bulbs transmit smell to the brain passes along olfactory tract to reach temporal lobe and olfactory areas

Question 28

what two factors must be present to allow a substance to be smelled

Answer 28

must be volatile and sufficiently water soluble so it can dissolve in the olfactory mucosa

Question 29

describe anosmia and what causes it

Answer 29

inability to smell

caused by infection, polyps, allergy and head injury

Question 30

describe hyposmia and what causes it

Answer 30

reduced sense of smell

can be earlier sign of parkinsons, polyps, allergy and infection