Taste and Smell

Chemical Senses – Taste and Smell Use chemoreceptors Complement each other Respond to many of the same stimuli

Olfaction – Sense of Smell Olfactory receptors in roof of nasal cavity Sniffing intensifies the scent and sense of smell by causing more air to flow across the receptors Chemicals must be dissolved in mucus for detection

Olfaction – Sense of Smell Olfactory receptor cells are neurons Have olfactory hairs that are bathed in mucus When receptors are stimulated by chemicals dissolved in mucus, they transmit impulses along the olfactory filaments

Olfaction – Sense of Smell olfactory filaments make up the olfactory nerve (cranial nerve 1) and then goes to the olfactory cortex of the brain Brain “memorizes” scent Olfactory system is closely tied into our emotional system (limbic) so different smells remind us of different situations…good/bad Olfactory neurons adapt quickly when exposed to unchanging stimuli and we can’t smell it anymore (Ex: restaurant, perfume, household smell, etc)

The Sense of Taste Taste buds house receptor organs…about 10,000 Location Tongue ** Soft palate Cheeks Figure 8.18a–b

Taste Buds Papillae (aka: projections) Filiform Fungiform** Circumvallate **

Structure of Taste Buds Gustatory cells are the receptors that respond to chemicals Gustatory hairs (long microvilli) go through taste pore Hairs stimulated by chemicals dissolved in saliva When taste pore is stimulated, they depolarize and impulses are transmitted to the brain through cranial nerves VII (Facial), IX (glossopharyngeal), and X (vagus)

Anatomy of Taste Buds Figure 8.18

Taste Sensations Sweet Sour Bitter Salty