TASTE/SMELL PT 1 Flashcards
what receptors are important for taste and smell and where are they?
chemoreceptors; tongue and nose
describe gustation/taste
Receptors excited by food chemicals
how does gustation/taste work
Dissolved molecules interact with receptors on tongue, parts of larynx, pharynx and epiglottis
describe olfaction/smell
Receptors excited by air chemicals dissolved in the nasal membrane (detects chemicals in a solution)
how does olfaction/smell work
Detects hazards, pheromones, food; Integrates with other senses to form sense of flavor
whats the olfactory epithelium
Organ with Pseudostratified epithelium that allows for smell; located on roof of nasal cavity
how do chemicals work on olfactory epithelium
Chemicals (odorants) dissolve in mucous of nasal epithelium
what happens after chemicals dissolve on olfactory epithelium
Interact with neurons (olfactory receptor cells) like any other neuron
Depolarizes neuron which sends action potential to olfactory bulb
what are the three types of cells on olfactory epithelium
Receptor cells (olfactory sensory neuron), Supporting cells, Olfactory stem cells
describe Receptor cells (olfactory sensory neuron)
millions on each side of nasal septum, (bowling pin-shaped)
describe supporting cells
cushion and surround olfactory cells (columnar shaped)
describe olfactory stem cells
base of epithelium (short cells)
what are bipolar neurons
neurons with two extensions
how are bipolar neurons structured
thin apical dendrite ends in a knob from which several long cilia radiate
what are olfactory cilia
Substantially increases receptive surface area
how do olfactory cilia lie
Lie flat on nasal epithelium; largely nonmotile
what are olfactory cilia covered by
mucus produced by the supporting cells and olfactory glands
what does that mucus do
captures airborne odorant chemicals
what do filaments of OSNs
project superiorly through the cribriform plate
what makes olfactory sensory neurons unique
noticeable turnover (superficial location – can be damaged)
how often are olfactory sensory neurons replaced
every 30-60 days by differentiation of olfactory stem cells
where does olfactory transduction occur
Ciliated OSN in nasal epithelium in nasal cavity
what do olfactory sensory neurons do
express odorant receptors
what do axons of OSNs that express the same receptors do
converge onto the same glomerulus at the olfactory bulb, allowing for organization of olfactory information
what happens after signals are transmitted to glomeruli
transmitted to higher regions of the brain
where do olfactory receptors send the action potential
to the second order neurons, mitral cells, inside glomeruli
do different glomeruli respond to different odors
yes
where do mitral cells send information and why
down the olfactory tract to either the thalamus or past the thalamus to the hypothalamus, amygdala, or limbic system (allowing the emotional responses to odors)
