Physiology Flashcards
what is the taste receptor q
taste bud
where are taste buds present, what are the types and how long do they live
present on tongue papillae, palate, epiglottis and pharynx 10 days vallete poliate fungiform filliform- no taste buds
describe how taste is passes to the brain
initiation of AP due to taste binding to receptor cell
conveyed to afferent nerve fibres and then onto chorda tympani, IX, X, to brainstem, thalamus, cortical gustatory areas
primary tastes
sweet salty sour bitter umami
cause of ageusia
nerve damage
endocrine
inflammation
cause of hypoguesia
drugs or chemotherapy
cause of dysguesia
chemotherapy glossitis gingivitis tooth decay reflux URTI drugs cancer zinc deficiency
neural systems of nose
CN I for olfactory purpose
CN V for somatosensory
describe the location of the olfactory epithelia and how smell reach it
sits in olfactory cleft, at cribiform plate, superior and small part of middle turbinate
retrograde airflow can reach from nasopharynx to aid taste
quiet respiration - needs to diffuse
sniff causes air to be drawn upwards
function of mucus in smelling
moist
protective
aids in dispersing odourants to olfactory receptors
describe the histology of the olfactory epithelia
pseudostratified columnar cells bipolar sensory neurons supporting cells bowmans gland basal cells
describe the function of olfactory receptors
endings of afferent neurons
pierce cribiform plate and enter olfactory bulb to transmit info back to brain into temporal lobe
conducting causes of anosmia
nasal polyps
nasal mass
rhinitis
sensorineural causes of anosmia
viral head trauma neurological drugs brain tumours
sound - frequency determines pitch/volume and amplitude determines pitch/volume
pitch
volume
what is the hearing range for humans
20Hz to 20,000Hz
describe the inner composition of the inner ear
scala media is suspended in the scala tympani/scala vestibuli
describe how sound in the inner ear becomes a nervous transmission
basillar membrane moves and moves hair cells, causing nervous stimulation
travels down VIII nerve to primary auditory complex
at what age in utero can a foetus hear
18wks
at what age in utero can a foetus respond to sound
26wks
at what age can children coo and recognise voice
3m
at what age can children babble cna make emotional sound
6m
at what age can children make simple noise and follow instruction
12m
at what age can children delete syllables, simplify syllables
12-18m
at what age can children say a few words
18m
at what age can children use two word phrases and know +50 words, follow command
24m
at what age can children use 3 word sentences, rhyme, understand word order
36m
types of hair cell in ear
stereocilia
kinocillium
what does the superior vestibular nerve supply
lateral/anterior SCC and utricle
what does the inferior vestibular nerve supply
saccule, post SCC
what do the utricle and saccule contain and what is their function
stereocilia projecting up into gel matrix with otoconia
lend weight and due to gravity the brain perceives postiion and movement on tilting head or linear motion
describe the vestibulo-ocular reflex
deflection caused by movement of perilymph, causing sterocilia to deflect and leading to eyes deflecting to opposure direction of head turning
what is the vestibulospinal tract
motor to neck, back, leg muslce
what is the medial longitudinal fasciculus
central pathway for ocular muscles
what is the medial lemniccus
central pathway to thalamus an cerebellum
