1. Suzanne D'Anna1 Taste

2. Suzanne D'Anna2 Taste Buds l about 10,000 are located on surface of tongue, throat, and epiglottis l Oval body consisting of three kinds of epithelial cells: - supporting cells - gustatory receptor cells - basal cells

3. Suzanne D'Anna3 Supporting Cells l form capsule supporting gustatory receptor cells l inside capsule - gustatory receptor cells Gustatory Receptor Cells l single hair-like gustatory hair projects from each bud to external surface through taste pore - hairs make contact with stimuli

4. Suzanne D'Anna4 Basal Cells l found at periphery of taste bud near connective tissue layer l produce supporting cells which develop into receptor cells whose life-span is about 10 days

5. Suzanne D'Anna5 Papillae l elevations on tongue l contain taste buds l give tongue rough appearance l Types of papillae: - circumvallate - fungiform - filiform

6. Suzanne D'Anna6 Circumvallate l largest l form v-shaped row on posterior surface of tongue Fungiform l mushroom-shaped l found on tip and sides of tongue

7. Suzanne D'Anna7 Filiform l thread-like l cover anterior 2/3 of tongue l contain no taste buds

8. Suzanne D'Anna8 Taste Sensations l Four basic: l sour - lateral edges of tongue l salty - anterior portions of tongue l bitter - posterior portions of tongue l sweet - anterior portions of tongue

9. Suzanne D'Anna9 Gustatory Pathway (once a chemical is dissolved in saliva) l contact is made with plasma membrane of gustatory hairs (site of transduction) l gustatory receptors - release neurotransmitter l nerve impulses arise in neurons that synapse with gustatory receptors l sensory fibers become part of three cranial nerves

10. Suzanne D'Anna10 Gustatory Pathway l Three cranial nerves: - facial (VII) - glossopharyngeal (IX) - vagus (X) taste impulses conduct from taste buds along cranial nerves to medulla oblongata

11. Suzanne D'Anna11 Gustatory Pathway l From medulla: - some taste fibers transmit impulses to hypothalamus and limbic system (emotional memory responses) - some taste fibers transmit impulses to primary gustatory area in parietal lobes of cerebral cortex (taste perception)