12/1/16 Taste Olfactory Flashcards
How many neurons on in the taste system?
-3 Neuron system
What is unique about the olfactory sense?
-It bypasses the thalamus and goes straight to the cortex
From the tongue what nucleus does taste go to?
-Nucleus solitarius
What three nerves do taste on the tongue?
- Facial nerve CN VII
- Glossopharyngeal nerve CN IX
- Vagus nerve CN X
From the solitary tract where do the taste neurons go to?
-VPM
T/F
Taste buds have no efferent neurons, they only have afferents.
True
What are the five tastes?
- Umami
- Sweet
- Bitter
- Sour
- Salty
What are the three major taste cell types in the oral cavity?
- Circumvallate
- Foliate
- Fungiform
How many buds do fungiform papilla have?
-2-4 buds each
How many buds to foliate papilla have?
2-9 clefts
How many buds to circumvallate have?
8-12
What CN innervates the foliate and fungiform papilla?
-CN VII Facial
What CN innervates the circumvallate papilla?
-CN IX Glossopharyngeal
What is the ganglia that CN VII uses on the initial neuron?
-Geniculate
What is the ganglia that CN IX uses on the initial neuron?
-Petrosal
What is the ganglia that CN X uses on the initial neuron?
-Nodose
Where does taste occur on the solitary nucleus?
-Rostral portion
Where does the first synapse occur in taste?
-Solitary nucleus
Where does the second synapse occur in taste?
-VPM
From the VPM in the taste sensation where do the neurons go?
Gustatory cortex (insula)
What does the insula receive?
- Taste
- Olfaction
Where do you find the Insula?
-The folds on the inside of the temporal lobe on the inside of the Sylvian fissure
T/F
Damage to the left insula disrupts addiction to cigarette smoking
True
Where do you bifurcate with olfaction?
-Olfactory Trigone
What does the Uncus do?
-Helps with memory and olfaction
Where is the first synapse in olfaction?
-Olfactory bulb
T/F
The olfactory neurons allow direct access to brain
True
Where does the second neuron in olfaction go?
–Either the medial or lateral trigone
If you go along the lateral trigone tract where do you go?
-Cortex
T/F
All smells concentrate in a single glomeruli even though the neurons are scattered throughout the nose
True
From the Olfactory bulb what are the 5 major regions that the 2nd synapse occurs?
- Anterior olfactory nucleus
- Olfactory tubercle
- Amygdala
- Piriform cortex
- Entorhinal cortex
If you synapse with the anterior olfactory nucleus what part of the trigone are you on?
-Medial tract
What are the two cell bodies in the secondary neurons used in olfaction?
- Mitral cell
- Tufted cell
What cells are inhibitory cells found in the olfactory pathway?
-Periglomerular cell
Where are three places you have highly processed information that takes the place of the thalamus in olfaction?
- Olfactory bulb
- Olfactory cortex
- Limbic and motor systems
What is Anosmia?
-Inability to detect odors
What is Hyposmia?
-Decreased ability to detect odors
What is Dysosmia?
-Distorted identification of smell
What is Parosmia?
-Altered perception of smell in the presence of an odor, usually unpleasant
What is Agnosia?
-Inability to classify or contrast odors, although able to detect odors
What causes Anosmia?
- Early neurodegenerative disorders
- Damage to olfactory epithelium
- Facial trauma
- Tumor
- Infection
- Chemical damage
How can you test wether CN I or CN V is damaged?
- Use a specific smell to test CN I
- Use capsasin/pepper to test CN V
What are two places in the brain the olfactory neurons are continually renewed throughout life?
- Olfactory
- Hippocampus
