Pathophysiology - olfaction, taste, vision, hearing, balance Flashcards
Flavor
the result of the combination of smell, taste, irritation, temp and texture - smell is most important contributor to flavor.
taste is often confused w/ olfaction. people consume food and beverages w/ a mixture of taste and smell
anosmia
lack of smell
hyposmia
decrease in smell; physiological effect of aging - olfactory receptors and bulb fibers decrease as does the ability to replace them; elderly also have decline in mucous production
dysosmia
distortion of smell (often happens w/ seizures)
ageusia
absence of taste
hypogeusia
decreased sensitivity of taste
dysgeusia
distortion of taste (usually d/t a comorbid condition that produces change in the amount of saliva - ex: flagyl causing metalic taste)
Who has a more sensitive sense of smell?
women - particularly around ovulation
Describe the specificity of olfactory receptors
There’s a specific receptor for each type of odiferous compound - you can percieve millions of different smells. To smell something, you only have to have a density in the air of a few ppm
How does sensitivity of olfaction vary?
varies widely among species. There is a genetic basis for some odors - your ability to smell certain things is inherited by genetic pattern (think N95 mask fit test)
pheremones
different kind of smell - not a conscious smell. Shut off sexual urges when smelling siblings pheromones
olfactory mucosa
top of nasal cavities; 10-20 million bipolar neurons that constantly regenerate 3-7 weeks - only neurons to do that in adult
primary odors
camphor, musky, floral, peppermint, ether, pungent and putrid
Where do olfactory neurons synapse?
on mitral cells of olfactory bulbs
Where do mitral neurons project to?
either clumps of neurons in the anterior olfactory nuclei or through olfactory trigone into striae
Where do medial stria project?
- anterior nucleus of the thalamus
- bulb of other side
- basal forebrain to modulate bulb neurons
Lateral stria fibers project to where?
to the uncus (actually medial part of amygdala which projects to the MD nucleus of the thalamus and hippocampus)
From uncus, fibers project where?
to primary olfactory cortex which is in the orbitofrontal area
What is smell tied in to?
thalamus and libmic system
What is unique to the pathway of the olfactory system?
it is the only sense projecting to the cortex (uncus) w/o first relaying through the thalamus
Where does the focus of seizure activity most often start?
in the uncus.
uncinate fits
right before a seizure starts in the uncus, people claim to smell the most awful smell
piriform cortex
amygdala, uncus, and parahippocampus. – all part of limbic system
When the thalamus receives info from the cortex, where does it project to?
the limbic system - attaches emotion to the perception of the environment
