ch. 6 - chemoreception

olfactory

smell

gustatory

taste

olfactory system

Highly sensitive in animals that have nose/antennae near the ground to pick up odorants

Olfactory receptor neurons (ORN)

olfactory receptor neurons

bipolar neurons in the epithelium of the nose

Receptors for odorants (similar to NT receptors)

Dogs have 1 to 4 BILLION ORNs while humans have 15 MILLION

ORNs send signals to cells in the glomeruli in the olfactory bulb (mitral cells)

mitral cells (olfactroy)

selectively sensitive to different classes of odors

Send signals to the entorhinal cortices, amygdala, and pyriform cortex

Does NOT pass through the thalamus

tastants

• chemicals associated with different flavors

  • Sweet, salty, sour, bitter, umami (glutamate)

taste papillae

bumps on the tongue

Different types (specific to tastant)

Trenches around papillae collect saliva and tastants

Contain taste receptor cells

Orbitofrontal Cortex (OFC)

integration of senses

Gustatory, visual, olfactory signals meet here

taste receptor cells

where transduction takes place

Supertasters

more papillae and more sensitive to bitter flavors