ANP 1106 Lecture 21: ANP1106 – Taste and Smell
29 Apr 2018
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ANP1106 – Taste and Smell
Taste Organ
- Tongue has papillae which gives it a rough texture
- 2 types of papillae:
o 1) Fungiform – on soft palate, cheeks, pharynx, epiglottis, end/sides of
tongue, 10000 of them
o 2) Circumvallate – back of tongue, 7-12 of them
- Papillae have taste buds consisting of 40-60 epithelial cells that form a taste
pore
- 3 types of epithelial cells:
o 1) Supporting cells
o 2) Gustatory cell – chemoreceptor, contains microvilli, no action
potential
o 3) Basal cells – renew supporting and gustatory cells every 7-10 days
- Moving from tip to back the chemical sensitivity goes from: salty, sweet,
sour/acid, bitter
- Umami – meaty flavor triggered by glutamate (MSG), found all over tongue
Taste Receptors
- 5 types of gustatory cells
o Salty – sodium in food crosses sodium channel to produce
depolarization, calcium entry and release of neurotransmitter
o Sour – hydrogen in food enters by sodium channel to produce
depolarization, calcium entry and release of neurotransmitter
o Sweet, Bitter, Umami – molecules bind to receptor to activate G
protein, stimulates increase in IP3, causes release of Ca stores to
trigger neurotransmitter release
- Neurotransmitters released will then activate neurons of:
o Facial VII nerves
o Glossopharyngial IX nerves
o Vagus X nerves
o *Gustatory cells release neurtransmitters and activate nerves, nerves
project to solitary nucleus in medulla, which projects to ipsilateral
thalamus, then projects to ipsilateral insular cortex = perception of
taste
Smell Organ
- Olfactory organ is in the roof of the nasal cavity
- Receptor area of olfactory system is made of epithelium which contains 3
kinds of cells:
o 1) Olfactory cells – cilia that detects odors, regenerate in 60 days
o 2) Supporting cells
o 3) Basal cells – regenerate other cells
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Document Summary
Anp1106 taste and smell tongue, 10000 of them potential sour/acid, bitter. 3 types of epithelial cells: 1) supporting cells. Papillae have taste buds consisting of 40-60 epithelial cells that form a taste. Tongue has papillae which gives it a rough texture. Moving from tip to back the chemical sensitivity goes from: salty, sweet, depolarization, calcium entry and release of neurotransmitter depolarization, calcium entry and release of neurotransmitter. Olfactory organ is in the roof of the nasal cavity. Receptor area of olfactory system is made of epithelium which contains 3: 1) olfactory cells cilia that detects odors, regenerate in 60 days, 3) basal cells regenerate other cells, 2) supporting cells. General mechanism of olfactory receptors = odor molecule activates a metabotropic receptor, opens a sodium channel/or closes potassium channel which causes depolarization of cell. Each 1 type of receptor is specialized for detecting 1 type of odor. The mitral cells of the olfactory bulb will send out projections.
