Which type of receptors are taste and smell receptors?
How is taste perception influenced?
What are the sense organs of taste?
What is the life span of a taste bud?
Taste receptor cells are replaced with what?
Where are taste buds mainly present?
What are the most abundant type of papillae on the tongue?
How is a depolarising receptor potential initiated within taste buds?
Taste provoking chemicals bind to receptor cells allowing ionic channels to open
How do afferent taste fibres reach the brainstem?
Chorda tympani (anterior 2/3rds)
Glossopharyngeal nerve (posterior 1/3rd)
Vagus nerve (other areas associated with taste)
How many primary tastes are there?
Which cell types are present in the olfactory mucosa?
- Olfactory receptor cells
- Supporting cells
- Basal cells (secrete mucous)
What comprises olfactory receptors?
Specialised endings of renewable afferent neurones
Each neurone associated with the olfactory receptors has what at one end?
Olfactory rod (expanded area)
What projects from the surface of the olfactory mucosa?
(to which odourants bind)
What act as precursors for new olfactory cells?
How does sensory information from the cilia assoaited with olfactory receptors reach the brain?
- Axons of olfactory nerves for afferent nerves
- Pierce cribriform plate and enter olfactory bulbs
- Olfactory bulbs pass signal along olfactory tracts
- Signal reaches temporal lobe and olfactory tract
Why does the act of sniffing enhance smelling?
Odourants only reach the smell receptors by diffusion otherwise
Which two characteristics does a substance require to be smelt?
- Sufficiently volatile
- Sufficiently water soluble (dissolves in mucus coating olfactory mucosa)
What is the term given to the inability to smell?
What are the causes of anosmia?
- Viral infections
- Nasal polyps
- Head injury
What is the term given to a reduced ability to smell?
Hyposmia may be an early sign for which condition?
What is the term given to an altered sense of smell?