Taste and Smell

This flashcard set contains definitions, concepts, and examples of the gustatory and olfactory systems. Taken from Behavioral Neuroscience (Breedlove & Watson, 2023), this was created as a study guide for Exam 3 in Behavioral Neurobiology at BYU-I.

Papillae

Small bumps on the tongue’s surface that contain most taste receptor cells

Taste buds

Clusters of 50-100 cells found in papillae that detect tastes

Three types of papillae

Circumvallate (back), foliate (sides), and fungiform (front, only about six taste buds) papillae

Taste pore

An opening of the taste bud where tastant molecules access sensory receptors

Tastants

Substances that can be tasted

Five basic tastes

Salty, sweet, sour, bitter, umami (savory/meaty)

Gustatory pathway

CN VII/IX/X, NST, VPN, insula (G1), OFC

Olfactory pathway

ORNs/ORCs - olfactory bulb (glomeruli) -
(mitral cells) - hypothalamus / amygdala / prepyriform cortex (primary olfactory cortex)

Anosmia

Odor blindness

Olfactory epithelium

A sheet of cells lining the nasal cavity, with supporting cells, basal cells, and olfactory receptor neurons, covered in mucosa

Olfactory receptor neurons (ORNs)

A type of neuron in the olfactory epithelium that senses airborne odorants

Dendritic knob

Portion of an ORN in the olfactory epithelium from which emerge numerous cilia

Olfactory bulb

Anterior projection of the brain that receives axons from ORNs, and organized into glomeruli

Glomeruli

Roughly spherical neural circuits, a complex arbor of dendrites from a group of olfactory cells in the bulb

Mitral cells

Cells in the olfactory bulb that synapse on axon terminals of ORNs to conduct smell information to the rest of the brain

Vomeronasal system

A specialized system that detects pheromones and transmits information to the brain

Vomeronasal organ

A collection of specialized receptor cells near the epithelium that detect pheromones and send electrical signals to olfactory bulb, present in most land mammals, amphibians, and reptiles

Trace amine-associated receptors (TAARs)

A newly discovered class of olfactory receptors that respond to volatile sex-specific urinary compounds (that may be pheromones)

Smell is the only modality that synapses directly in the cortex instead of being transmitted to the __________.

Thalamus

Turbinates

The complex, curved surfaces that form the nasal cavity, guiding odorants during inhalation, sniffing, and chewing

Golf (G protein)

A second messenger that mediates olfaction, depolarizing the ORN to generate action potentials

Major histocompatibility complex (MHC) molecules

Molecules that interact with V2R (vomeronasal) receptors, possibly playing a role in the avoidance of inbreeding