Chapter 8 Chemical Sense: Smell Flashcards
What are the three main cell types in the olfactory epithelium (OE)?
Olfactory receptor cells, supporting cells, basal cells
What do supporting cells do?
Produce mucus
What are olfactory receptor cells?
They are the site of transduction and are constantly regenerated throughout life.
What do basal cells do?
Source of new receptor cells
Where are the receptors on the olfactory receptor neuron?
Cilia
What are cilia?
Cilia are specialized dendrites, extending into mucus layer.
What type of receptors are odorant receptors?
They are G-proteins called G-OLF
What is the process of transduction for olfactory receptor neurons?
- Odorant molecules binds to GPCR.
- Alpha subunit stimulates adenylyl cyclase.
- Adenylyl cyclase uses ATP to turn it to cAMP.
- Increased cAMP opens a cAMP-gated cation channel leasing to influx of Na+ and Ca2+.
- Increased Ca2+ activates Ca2+ -gated Cl- channel leading to Cl- efflux which depolarizes the cell, a receptor potential.
- Depolarization triggers an AP in the soma and sending APs out of the olfactory nerve.
How are olfactory receptors broadly tuned?
Each odorant activates multiple receptor and each receptor responds to multiple odorants.
How many glomeruli does a specific cell has?
Cells expressing a given gene go to only 2 glomeruli in each bulb
What are olfactory maps?
They maximize sensitivity to low concentrations of odorant and important for stimulation of odor memories.
Where do glomeruli send info?
2nd order ORNS
What is one of the olfactory pathways?
Olfactory epithelium to Olfactory bulb and second-order neurons project to piriform cortex in the olfactory tract.
What information sent to the piriform have to do with?
Mediate emotion, motivation, memory effects of odors
What is the other olfactory pathway?
Olfactory epithelium to Olfactory bulb and second-order neurons project to olfactory tubercle to thalamus to orbitofrontal neocortex.
