Chapter 15: taste and smell

olfaction

smell

gustation

taste

odors

perceptual experience of odorants

odorants

molecules our olfactory system respond to when we detect them in the air

nasal septum

wall of cartilage that separates nostrils

where you get pierced

turbinates

bony knots of tissue that disperse air in the nasal cavity

olfactory cleft

channel at the back of the nasal cavity that funnels air up to the olfactory epithelium

olfactory epithelium

mucous membrane inside each nostril that contains receptor cells

olfactory receptor neurons

receptor cells in the epithelium that detect specific chemicals in the air and transduce them into a neural signal

supporting cells

provide metabolic supplies to olfactory receptor neurons

basal cells

create olfactory receptor neurons

macrosmatic

species that are heavily dependent on their olfactory system

microsmatic

species that are less dependent on their olfactory system

trigeminal nerve

associated with the feel of odorants

5th cranial nerve

cribriform

perforated section of skull bone that separates the nose from the brain

• axons from olfactory receptor neurons pass through to allow info to enter regions of the brain

anosmia (smell blindness)

inability to smell

usually caused by cribriform plate damage

olfactory nerve 1st cranial nerve

axons of the olfactory receptor neurons that leave the nose and enter the olfactory bulb

olfactory bulb

part of the brain right behind the nose

first part of the brain where olfactory information is processed

glomeruli

spherical structures in the olfactory bulb where the tract forms synapses with mitral cells and tufted cells

mitral cells

neurons that start in the glomeruli of the olfactory bulb and project to other areas of the brain

• responds to diff odorants that tufted cells

tufted cells

neurons that start in the glomeruli of the olfactory bulb and project to other areas of the brain

• respond to diff odorants that mitral cells

olfactory tract

pathway leading from olfactory bulb to other regions of the brain

amygdala

in the limbic system

• experience of emotion and fear

entorhinal cortex

in medial temporal lobe

associated with memory functions

piriform cortex

in the anterior region of the temporal lobe that receives input from the olfactory bulb and is does olfactory processing

• considered primary olfactory cortex

anterior piriform cortex

front portion of the piriform cortex

• represents chemical structures of odorants

posterior piriform cortex

in the back portion of the piriform cortex

• odor quality (regardless of chemical composition)

orbitofrontal cortex

part of the prefrontal cortex

• critical for emotional experience of odors

• also integrates smell in taste perception

tastants

molecules recognised by taste receptors that induce responses in taste receptors on the tongue

taste

perception of transduction of tastants along the surface of the tongue

flavor

combined sensory experience of a good

taste + odor + effect on trigeminal nerve ( and sometimes visual experience)

taste buds

small structures on the surface of the tongue or mouth that contain receptor cells

papillae

small structures that contain taste buds

fungiform papillae

mostly along edges and top of tongue

respond to all 5 basic tastes

foliate papillae

along side of tongue

respond to all 5 basic taste

circumvallate papillae

very back of tongue in a row

all 5 basic tastes

filliform papillae

all over the tongue

somatosensory receptors rather than taste buds

feel food but not taste it

taste receptor cells

cells within the taste buds that tranduce tastants into a neural signal

receptor cells

transduce sweet tastes, umami tastes, and bitter

presynaptic cells

transduce salty and sour

anterior insular cortex (insula)

part of the frontal lobe that serves as the primary taste cortex

tasters

people who can detect bitter compounds

Have PAV form of TAS2R38 gene

nontasters

people who cannot detect bitter compounds except at high concentrations

supertasters

people extremely sensitive to bitter tastes

typically don’t like foods with bitter compounds

phantosmia

hallucinatory perception of odors

ageusia

loss of ability to taste