Summarizing Taste and Smell

Summary

There are five primary tastes in humans: sweet, sour, bitter, salty, and umami. Each taste has its own receptor type that responds only to that taste. Tastants enter the body and are dissolved in saliva. Taste cells are located within taste buds, which are found on three of the four types of papillae in the mouth.

Regarding olfaction, there are many thousands of odorants, but humans detect only about 10,000. Like taste receptors, olfactory receptors are each responsive to only one odorant. Odorants dissolve in nasal mucosa, where they excite their corresponding olfactory sensory cells. When these cells detect an odorant, they send their signals to the main olfactory bulb and then to other locations in the brain, including the olfactory cortex.

Glossary

bipolar neuron

neuron with two processes from the cell body, typically in opposite directions

glomerulus

in the olfactory bulb, one of the two neural clusters that receives signals from one type of olfactory receptor

gustation

sense of taste

odorant

airborne molecule that stimulates an olfactory receptor

olfaction

sense of smell

olfactory bulb

neural structure in the vertebrate brain that receives signals from olfactory receptors

olfactory epithelium

specialized tissue in the nasal cavity where olfactory receptors are located

olfactory receptor

dendrite of a specialized neuron

papilla

one of the small bump-like projections from the tongue

pheromone

substance released by an animal that can affect the physiology or behavior of other animals

tastant

food molecule that stimulates gustatory receptors

taste bud

clusters of taste cells

umami

one of the five basic tastes, which is described as “savory” and which may be largely the taste of L-glutamate