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What is olfaction
Smell
What is gustation
taste
What allows for smell
Substances dissolved in fluids of the nasal membranes
What allows for taste
Substances dissolved in saliva
What do chemoreceptors respond to?
Chemicals in solution
What are the six qualities of taste?
Bitterness, sourness, sweetness, saltiness, umami, and fat
What is umami?
Savory taste
What is the stimulus for taste?
Tastants which are associated with specific molecules that activate certain receptors
What causes sweet
Complex organic molecules
What causes salty
sodium ions in solution
What causes sour
Acidic ions in solution, H+ ions
What causes bitter
Complex organic and inorganic molecules
What causes umami
glutamate and ribonucleotide
What is the tonuge covered with
papillae
What are papillae
Bumps of the surface of the tongue
Where are taste buds located
in the papillae
What are the four different kinds of papillae
Fungiform, foliate, circumvallate, and filliform
Fungiform
On the tips and anterior sides of the tongue. Detect differences in the nature of food (ex: temp)
Foliate
Rear sides of the tongue. Contain tastebuds for sour and bitter flavors
Circumvallate
Across the back of the tongue. Most sensitive to the bitter taste
Filliform
Contains no taste buds
Do taste buds live for a long time?
No
There are 3 cranial nerves that innerate the tongue. Where do they project to?
The solitary nucleus of the medulla to the thalamus to the tongue region of the somatosensory cortex
What is the only sensation that communicates ipsilateral?
Taste
Between what two structures is there cross communication of the tongue region of the somatosensory cortex?
The frontal lobe and the basal ganglia (reward pathway)
Where is the olfactory epithelium located
In the nasal cavity (under frontal lobe)
What is the organ of smell?
The olfactory epithelium
What type of cells does the olfactory bulb communicate with?
Mitral cells
What do oder molecules do?
They dissolve in mucous and stimulate G proteins on olfactory receptors (Golf) which causes a chemical reaction
Where do mitral cells send impulses to?
The piriform cortex, frontal area, and the limbic area
What is the piriform cortex
It’s the primary cortical olfaction area
Frontal area
Scent identification
Limbic area
emotional area (fast)
How many odorants can we recognize
10,000
How many different olfactory receptors do we have
339
What are the two main theories for odor detection?
Lock and key theory, and the alternative theory
What is the lock and key theory?
Odorant molecules bind to multiple receptors
What is the alternative theory?
The pattern of activity across several receptors that encodes an odor. Happening in the cortex not the epithelium. More like an association
