Neuroanatomy of Taste and Olfaction Flashcards
Olfactory fila
What do they become?
Bundles of the olfactory receptor neurons before theu pass thru the cribiform plate.
CN I
Where does olfactory discrimination begin?
In the olfactory epithelium.
What is the “receptor map”?
A map of ORNS (that only express 1 type of odorant receptor) and are distributed within the epithelium.
What attaches the brain to the olfactory bulb?
Olfactory tract
What does the olfractory tract contain? (3)
Fibers of lateral olfactory tract.
Cells of anterior olfactory nucleus.
Fibers of the anterior limb of anterior commissure.
How do centrifugal fibers reach the olfactory bulb?
What is their function?
Via the anterior commissure.
Modulate the function of olfactory microcircuits at glomerulus.
5 layers of olfactory tract (superficial to deep)
- Olfactory n. layer
- Glomerular layer
- External plexiform layer
- Mitral cell layer
- Granule cell layer
Which cells of the olfactory tract are inhibitory?
Granule cell (principle interneuron) Periglomerular cell
What do glomerular cells synapse with?
What are they known as together?
Mitral and tufted cells.
Outflow tract of the olfactory tract (lateral olfactory tract).
External plexiform layer contains which cells? (3)
Tufted cells (and their dendrites), mitral cells, granule cells.
Which cells of the olfactory tract do not have axons?
Granule cells
What forms the lateral olfactory tract?
Axons of mitral and tufted cells.
Where does the olfactory bulb project?
To the olfactory cortex in telencephalon. NOT the thalamus.
Parts of the olfactory cortex (6)
Anterior olfactory nucleus Olfactory tubercle Piriform cortex Anterior cortical amygdaloid nucleus Periamygdaloid cortex Lateral entorhinal cortex
Where does the anterior olfactory nucleus project? (2)
BL olfactory bulb
CL anterior olfactory nucleus
What are the major olfactory cortical projections?
Insular cortex
Orbitofrontal cortex
Dorsomedial nucleus (thalamus)
Orbitofrontal cortex’s job
Integration of olfactory, taste and food-related cues that give an experience of flavors.
Where do the olfactory cortical projections go (after the cortex)? What do they do?
Lateral hypothalamus (feeding behavior) and hippocampus (olfactory input to learning and behavior).
Anosmia
Hyposmia/Olfactory hypesthesia:
What is it associated with?
Loss of smell.
Decreased sensitivity to odorants. Nasal polyps.
What does greater superficial petrosal n. innervate?
Taste buds on soft palate
Where are cell bodies of CN VII for taste?
Geniculate nucleus
Where are cell bodies of CN IX and X for taste?
Petrosal and nodose ganglia
What branch of CN IX innervates the posterior tongue?
What branch of CN X innervates the epiglottis and esophagus?
Lingual-tonsillar branch
Superior laryngeal n.
What is the peripheral pathway for CN VII?
Enter brainstem at pontomedullary junction via internediate n. –> solitary tract –> gustatory nucleus (of solitary nucleus)
