Ch 15: Olfaction

Olfactory bulb

a part of the brain just behind the nose that is the first place in the brain where olfactory information is processed

Orbitofrontal cortex

a part of the prefrontal cortex that appears to be critical in the emotional experience of odors and integrating olfaction and taste perception, among other functions

cribriform plate

a perforated section of skull bone that operates the nose from the brain; axons from olfactory receptor neurons pass through to allow olfactory information to enter regions in the brain

tip-of-the-nose phenomenon

a phenomenon that occurs when a person is familiar with an odor but cannot recall its name, despite feeling as if he or she can

Posterior piriform cortex

a structure located in the back portion of the piriform cortex that is associated with an odor's quality, regardless of its chemical composition

Anterior piriform cortex

a structure located in the front portion of the piriform cortex that is associated with representing the chemical structures of odorants

Piriform cortex

an area in the anterior region of the temporal lobe that receives input from the olfactory bulb and is involved in olfactory processing; often considered the primary olfactory cortex

Entorhinal cortex

an area in the medial temporal lobe, associated with a number of memory functions

amygdala

an area of the brain in the limbic system, associated with the experience of emotion, particularly fear

olfactory receptor neurons

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

anosmia

the inability to smell, usually caused by cribriform plate damage

Trigeminal nerve

a nerve that is associated with the feel of odorants: cranial nerve V

mitral cells

___ ___ are more likely to inhibit the olfactory process

verbal labeling, Stevenson

___ ___ can cause olfactory illusions and can affect whether the participant perceives a positive or negative smell and was demonstrated by _____ who found that the first label of a smell influenced the perception more

color

___ was found to influence smell even when there was no smell present in liquids

olfactory epithelium

a mucous membrane inside each nostril of the nose that contains the receptor cells for the olfactory system

turbinates

bony knots of tissue that serve to disperse air within the nasal cavity

basal cells

cells that create olfactory receptor neurons

supporting cells

cells that provide metabolic supplies to the olfactory receptor neurons

different

different odorants require ___ concentrations to be detected

discrimination

distinguishing between two stimuli

imagery

experiencing a sensory experience that is previously known but not presently experienced is known as olfactory ___

olfactory rivalry

in ___ ___ one odorant is presented to one nostril, and a different odor presented to the other. People reported smelling one and then the other but not both at the same time

Lawless

in ___'s illusion a chemical smelled woody when surrounded by citrus and citrusy when surrounded by woody

inactive

in humans we only use 350 of 1,000 genes coding for sense of smell, most are ____

odorants

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

mitral cells

neurons that start in the glomeruli of the olfactory bulb and project to other areas of the brain; respond to different odorants than do tufted cells

Tufted cells

neurons that start in the glomeruli of the olfactory bulb and project to other areas of the brain; they respond to different odorants than do mitral cells

parts per million (ppm)

odor is measured in ___ ___ ___

28

olfactory receptor neurons are completely regenerated every ___ days

cilia

olfactory receptor neurons have ___ extending into the mucus covering of the olfactory epithelium where a chemical triggers the cilia causing a neural signal to begin

memory, emotion

smell is associated with ___ and ____

microsomatic

species (such as humans) that are more dependent on vision and audition are called ___

macrosomatic

species that depend heavily on smell are called ____

glomeruli

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

olfactory nerve

the axons of the olfactory receptor neurons that leave the nose and enter the olfactory bulb. Cranial nerve I

odorant map

the cells in the glomeruli form an ___ ___ that organizes chemicals with similar structures near one another

olfactory cleft

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

olfactory tract

the pathway leading from the olfactory bulb to other regions of the brain

odors

the perceptual experience airborne chemical stimuli

olfaction

the sense of smell

gustation

the sense of taste

nasal septum

the wall of cartilage that operates the nostrils

20 million

there are approximately ___ ____ olfactory receptor neurons in the human nose, more than any other sense

language

there seems to be a disconnect between olfaction and ___