Lab Exercise 26
Special Senses:
Olfaction and Taste
Objectives
Olfactory epithelium


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)
Fig. 17-2
Gustatory (taste) cells—
receptor cells, w/ microvilli
Supporting cells
Taste Buds (Receptors)
Fig. 17-2
Nerve fibers enter each
taste bud, to each taste cell
Certain chemicals detected
by microvilli “activate” the
taste cell
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