physiology of taste and smell? Flashcards
which 3 bones is the tongue suspended from?
mandible, hyoid and silos
which 3 muscles does the tongue extend from?
genioglossus
hyoglossus
styloglossus
how much of the tongue is visible?
anterior 2/3
where are the tastebuds located?
on the fungiform papillae
roughly how Many taste buds do we have?
2000-8000
what are the five primary tastes?
sour
salty
sweet
bitter
savoury
what chemicals are sour?
acid
H+
what chemicals are salty?
Na+
what chemicals are sweet?
glucose
what are bitter?
coffe
beer
quinine
blue cheese
olives
what are savoury?
glutamate
what is the pathway of taste from the anterior 2/3 of tongue?
lingual nerve (trigenminal V)
then to chorda tympani (facial VII)
what is the most sensitive taste bud?
bitterness for protective properties
what nerve controls taste from the posterior 1/3 of tongue?
glossopharyngeal nerve
where do the glossopharyngeal and facial nerve take the taste messages?
up to the brain stem and the taste fibre synapse in the nucleus of the solitary tract which lies in the medulla
what happens if you damage the chorda tympani?
unilateral - minimal symptoms
bilateral - unpleasant metallic taste in the mouth
how long is the horizontal structure of the nose?
7cm
what is quiet breathing?
low resistance laminar airflow over the inferior turbinate
what happens when you sniff something?
turbulence to mix the air and send odorant’s to the roof of the nose
where do the olfactory mucosa sit?
just below the cribriform plate, olfactory bulbs sit just above
how many olfactory receptors are active in mammals?
400
what happens to odorant molecules in the air?
dissolve in nasal mucus
detected by rhodopsin like detectors on dendrites of olfactory cells
how many different smells can be recognised?
range from 10,000 to more than a trillion
what does the detection threshold depend on?
-solubility
-pH
-number of receptors
generally parts per billions
what is the only sensory modality that dosent relay to the thalamus?
smell
what is the pathway for smell?
goes straight to the limbic system - emotion and memory
where does the olfactory nerve project to?
-amygdala
-hippocampus
-parahippocampal gyrus
what may cause a loss in smell?
-rhinosinusitis
-neurological disorders (alzheimers, parkinsons, MS)
-base of skull fracture
-brain tumour
-COVID-19
