Physiology of Smell Flashcards
What 3 cell types are contained in the olfactory mucosa?
olfactory receptor cells
supporting cells
basal cells - secrete mucus
What are the features of olfactory receptors?
specialised endings of renewable afferent neurones
each neurone has a thick short dendrite and an expanded end called an olfactory rod
cilia project from the olfactory rods to the surface of the olfactory mucosa
odrants bind to the cilia
What is the lifespan of olfactory receptors?
2 months
What act as precursors for new olfactory receptor cells?
basal cells
What do the axons of olfactory receptors collectiveley form?
olfactory nerve
How do the afferent fibres of the olfactory nerve get to the olfactory bulb in the brain?
peirce the cribiform plate of the ethmoid bone
What is the role of the olfactory bulb?
transmit smell information to the brain
How do olfactory bulb neurones reach the temporal lobeand olfactory areas?
pass along the olfactory tract
How do odrants reach the smell receptors in quiet breathing?
diffusion
What must a substance be to be able to be smelled?
sufficiently volatile
sufficiently water soluble
What is Anosmia?
inability to smell - permanent or temporary
What can cause Anosmia?
viral infections
allergy
nasal polyps
head injury
What is Hyposmia?
reduced ability to smell
What may Hyposmia be a sign of?
early Parkinsons
What can cause Hyposmia?
viral infections
allergy
nasal polyps
head injury
