Physiology of Taste and Smell Flashcards
What type or receptors and taste and smell receptors?
chemoreceptors
What can taste and smell influence?
flow of digestive juice
Can taste perception be influenced by smell?
Yes
Where are taste receptors found?
taste buds (organs of taste)
What else to taste buds contain?
support cells, basal cells
How are cells arranged in taste buds?
like orange slices
What is the life span of taste receptor?
10 days
Where are taste buds found?
mainly in tongue but also palate, epiglottis, pharynx
Which type of papillae in the tongue does not contain taste buds?
filiform
What type of nerve fibres do taste receptors synapse with?
afferent
Where are signals conveyed to via the brainstem and thalamus?
cortaid gustatory areas
Which nerve carries signals from anterior 2/3rds of tongue?
VII
Which nerve carries signals from posterior 3rd of tongue?
IX
Which nerve carries signals from areas other than tongue eg pharynx?
X
Name the 5 primary tastes.
salty, sweet, sour, bitter, unami (meaty or savoury)
What often triggers unami tastes?
amino acids especially glutamate
What is loss of taste function called, and what might cause it?
ageusia
endocrine, nerve damage, local inflammation
What is reduced taste called and what causes it?
hypogeusia
chemotherapy, medications
What is distortion of taste called and what might cause it?
dysgeusia
mainly infections, tooth decay etc
What are the three types of cell olfactory mucosa contains?
olfactory receptors
support cells
basal cells
Neurons in olfactory receptors each have what?
a thick short dendrite and an expanded end called an olfactory rod
What project to the surface of the olfactory mucosa from the olfactory rods?
cilia
What do odorants bind to?
cilia
What do axons of the receptors pierce and then enter?
cribiform plate of ethmoid, enter olfactory bulbs
During quiet breathing, what is the only way odarants may be smelled?
diffusion
What enhances smelling drawing air currents into nasal cavity>
sniffing
What two things must an odarant be to be able to be smelled?
sufficiently volatile and water soluble
What is anosmia?
inability to smell
What might cause anosmia?
viral infections, allergy, nasal polyps, head injury
What is hyposmia and what may cause this?
reduced ability to smell
as with anosmia, or may be early sign of Parkinson’s
Dysosmia is what? What are examples?
altered sense of smell
eg hallucinations of smell, or differently interpreting odours
