Physiology of Taste + Smell Flashcards
What type of receptors are taste + smell receptors?
Chemoreceptors
What are the sense organs of taste?
Taste buds
What is the lifespan of sensory taste receptor cells? Which cells are they renewed from?
10 days
Renewed from basal cells
Where are the majority of taste buds located?
In the papillae of the tongue
What are the 4 types of papillae on the tongue?
Filiform
Fungiform
Vollate
Foliate
All the papillae on the tongue have taste bud associations. True/False?
False
Filliform papillae do not have taste buds
Which cranial nerves supply afferent taste fibres?
VII (facial) - chorda tympani - anterior 2/3 tongue
IX (glossopharyngeal) - posterior 1/3 tongue
X (vagus) - pharynx, epiglottis etc.
What are the 5 main types of taste and their stimulants?
Sweet: glucose
Salty: NaCl
Sour: H+ ions
Bitter: diverse - toxins, poisons, alkaloids
Umani (meat/ savoury): glutamate, amino acids
What is aguesia?
Loss of taste function
List some causes of aguesia
Nerve damage
Inflammation - glossitis, radiation, endocrine disorder
What is hypoguesia?
Reduced taste function
What is disguesia?
Distortion of taste function
Which mucosa is associated with smell?
Olfactory mucosa
What are the 3 main types of cell located in olfactory mucosa?
Olfactory receptor cells
Supporting cells
Basal cells (precursor for new receptor cells)
What is the lifespan of olfactory receptor cells?
2 months
What is the course of the olfactory nerve afferents from the olfactory mucosa?
Pierce the cribriform plate of ethmoid + enter olfactory bulb in anterior cranial fossa
In order to be smelled, a substance must be what?
Sufficiently volatile (can enter nose with inspired air) Sufficiently water soluble
What is anosmia?
Inability to smell
What is hyposmia?
Reduced ability to smell
What is dysmosia?
Altered sense of smell
Binding of tastant to receptor results in what type of action potential?
Depolarising
What structure in the nasal cavity do odorants bind to?
CIlia at the olfactory mucosa
Hyposmia is an early sign of which neurodegenerative disease?
Parkinson’s disease
List causes of anosmia
Viral infection, allergy, nasal polyps, head injury
