human anatomy physiology - ia highlands：人体解剖学生理学--佐治亚州高地....ppt

Special SensesUtilize distinct receptor cells as receptorsChemical sensesuTaste (gustation)uSmell (olfaction)TasteuTaste buds.?Most are on the tongue.?Papillae.–Filiform - rough, conical shape, few taste buds–Fungiform– scattered; most numerous on sides and tips–Circumvallate–largest; least numerous; back of tongueStructure of a taste cells – form bulk, insulateuReceptor (Gustatory or Taste) cells –contain gustatory hairs that extend through surfaceuBasal cells - stem cells that divide giving rise to new gustatory cellsTaste sensationuSour – stimulated by acidsuSweet – stimulated by sugars, alcohols, some amino acidsuBitter – stimulated by basesuSalty – stimulated by metal ions Sensitivity of the taste buds in different tongue is more sensitive to sweet and salty substancesuPosterior tongue is more sensitive to bitter tongue is more sensitive to sour of in contact with gustatory hair cells on receptor of taste cells results in generation of action potentials in associated sensory to the gustatory sensations?Taste is 80% smell?Affected by temperature; texture; heatSmelluLocalization and structure of olfactory receptorsuDetects chemicals in solutionuOlfactory epithelium - Contains the olfactory receptors and is located in the roof of the nasal cavity.