Special Senses: Olfaction and Taste Lab Exercise 26 Special Senses: Olfaction and Taste

Objectives Olfactory epithelium Taste receptors Taste sensation Location Cellular composition Taste receptors Structure, function Location on tongue Taste sensation 4 basic qualities Chemical substances that elicit them

What is Olfaction? SMELL Olfactory Epithelium (smell organ) Covers inferior surface of cribriform plate, superior perpendicular plate, & superior nasal conchae Fig. 17-1

Cellular Composition Olfactory epithelium: Olfactory receptor cells (ciliated) Supporting cells Basal (stem) cells Olfactory nerve fibers Fig. 17-1

Sense of Taste Dorsal tongue’s surface covered with papillae (small projections)—3 types Taste buds (receptors) primarily on sides of ones at posterior tongue (“V”) and small ones all over mid-tongue Fig. 17-2

Taste Buds (Receptors) 2 types of cells (epithelial) Gustatory (taste) cells—receptor cells, w/ microvilli Supporting cells Fig. 17-2

Taste Buds (Receptors) Nerve fibers enter each taste bud, to each taste cell Certain chemicals detected by microvilli “activate” the taste cell Fig. 17-2

4 Primary Taste Sensations Sour Acids Bitter Quinine, PTC Salty Salt, NaCl Sweet Sugars, saccharin, amino acids

Plotting Taste? “No differences in the structure of the taste buds, and taste buds in all portions of the tongue provide all 4 primary taste sensations.” --Text, Martini “A single taste bud contains 50–100 taste cells representing all 5 taste sensations (so the classic textbook pictures showing separate taste areas on the tongue are wrong).” --http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/T/Taste.html