Physiology Flashcards
what does frequency dictate
pitch
what does amplitude dictate
intensity
list the functions of the external, middle and inner ear
external - receives sound
middle - amplifies sound by moving fluid
internal - converts sound into neurological impulse
what are the two windows in the inner ear and their function
oval and round windows
permit transmission of pressure wave in enclosed canal and vibration of basilar membrane
where is the eustachian tube connected to
connects the middle ear to the nasopharynx
what is the function of the eustachian tube
ventilation pathway for middle ear mucosa
name the two otolith organs and their function
utricle and saccule
have sensors for balance, coordination and direction of movement
what is the vestibulo-ocular reflex
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
describe nystagmus
fast involuntary movements of the eye
what type of receptors are taste and smell receptors
chemoreceptors
where are the taste receptors located
taste buds - organs of taste
where in the body are the taste buds found
on papillae of the tongue
name the 4 types of papillae and which one lacks taste buds
filiform - lacks taste buds
fungiform
vallate
folliate
describe the chemical mechanism of taste
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
which CN supplies afferent taste fibres to brainstem from anterior 2/3rds of tongue
CN VII - via chorda tympani branch of facial nerve
which CN supplies afferent taste fibres to brainstem from posterior 1/3 of tongue
CN IX - glossopharyngeal nerve
which CN supplies afferent taste fibres to brainstem from epiglottis and pharynx
CN X - vagus nerve
list the 5 primary tastes and what molecules they contain
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
what is ageusia and what causes it
loss of taste function
caused by nerve damage, local inflammation eg glossitis and radiation
what is hypogeusia and what causes it
reduced taste function
some medications or chemotherapy
what is dysgeusia
distorted taste function
caused by medications, chemotherapy, neoplasms and infection
what is olfaction
sense of smell
where is the olfactory mucosa located
in the dorsal roof of the nasal cavity
what 3 types of cells are found in olfactory mucosa
olfactory cells
supporting cells
basal cells - secrete mucus and precursors for new olfactory receptor cells
what is the lifespan of taste buds
10 days
what is the lifespan of olfactory cells
2 months
describe how smell travels to the brain
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
what two factors must be present to allow a substance to be smelled
must be volatile and sufficiently water soluble so it can dissolve in the olfactory mucosa
describe anosmia and what causes it
inability to smell
caused by infection, polyps, allergy and head injury
describe hyposmia and what causes it
reduced sense of smell
can be earlier sign of parkinsons, polyps, allergy and infection
