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Chapter 17. Olfaction and Taste. Anatomy of the olfactory receptors. Olfactory epithelium Olfactory receptors are localized on the roof of the nasal cavity. Covered by mucus. Bipolar neurons with cilia Supporting cells Basal cells – stem cells Olfactory glands
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Chapter 17 Olfaction and Taste
Anatomy of the olfactory receptors • Olfactory epithelium • Olfactory receptors are localized on the roof of the nasal cavity. Covered by mucus. Bipolar neurons with cilia • Supporting cells • Basal cells – stem cells • Olfactory glands • Responsible for mucus production
Anatomy of the olfactory receptors • Olfactory nerves • Penetrates the ethmoid bone • Olfactory bulb • Olfactory tracts • Cerebral cortex – uncus • Olfactory adaptation • Partial adaptation: 3-5 seconds • Complete adaptation: 1-5 minutes
Taste receptors – gustatory cells • Clustered in taste buds • Associated with lingual papillae • Types of lingual papillae • Filiform- The more numerous one. No tastebuds • Fungiform – mushroom-like. Contain taste buds • Circumvallate- on a V formation on the back of the tongue. Contain taste buds
Taste buds • Basal cells • Stem cells • Supporting cells • Insulate the gustatory cells • Gustatory hair • Seems to be the sensitive portion of the taste cells • They are microvilli • Taste pores • Opening for the gustatory hair
Gustatory pathways • Taste buds are monitored by cranial nerves • Facial– anterior 2/3 of the tongue • Glossopharyngeal- posterior 1/3 of the tongue • Vagus –taste buds on the pharynx • Synapse within the solitary nucleus of the medulla oblongata • Thalamus • Trigeminal– will carry all the other information such as texture, and temperature
Taste buds distribution • Sweet receptors • Sugar and some aminoacids • Salt • Metallic ions • Sour • Acid solutions • Bitter • alkaloids • Umami • Cheese, meat taste
Gustatory discrimination • Combine effects of smell, texture and temperature on taste