Olfaction and Gustation

where are special sensory receptors located?

within a special sensory organ or a distinct part of epithelium

what are the special senses?

olfaction, gustation, audition, equilibrium, vision

what are the types of general senses?

touch, pain, temperature

what type of senses are associated with this neuron?

general senses

what type of senses are associated with this type of neuron?

taste, light, sound, head movement

what sense is associated with this type of neuron?

smell

what is olfaction?

sense of smell

what are olfactory receptors?

chemoreceptors

what do olfactory receptors respond to?

chemicals in solution

what is the solution that chemicals are dissolved in to allow us to smell?

fluids of the nasal mucous membrane

due to location, what does sniffing do?

enhances smell

what is A?

olfactory epithelium

what is B?

olfactory tract

what is C?

olfactory bulb

what is D?

nasal conchae

what is E?

olfactory nerves

where is olfactory epithelium found?

in roof of nasal cavity

what does olfactory epithelium cover?

superior nasal conchae

what does the olfactory epithelium contain?

olfactory sensory neurons

what do bundles of nonmyelinated axons of olfactory receptor cells form?

olfactory nerves

what is the structure of Olfactory receptor cells/ sensory neurons?

bipolar neurons with cilia that

what do supporting cells and olfactory glands in the olfactory epithelium do?

produce mucus

what do basal (stem) cells do in the olfactory epithelium?

replace receptor cells every 60 days because they’re mitotic

what is A?

olfactory tract

what is B?

olfactory gland

what is C?

olfactory epithelium

what is D?

mucus

what is E?

mitral cell

what is F?

olfactory bulb

what is G?

cribriform plate of ethmoid bone

what is H?

lamina propria

what is I?

olfactory axon

what is J?

basal/stem cell

what is K?

olfactory sensory neuron

what is L?

supporting cell

what is M?

olfactory cilia

what is converted during smell transduction?

chemical energy into electrical energy

what is the first step in smell transduction?

chemical in air (odorant) dissolves in mucus

what happens in smell transduction after the odorant is dissolved in mucus?

cilia of dendrite interacts with chemical odorant

what happens in smell transduction after the cilia of a dendrite interacts with the chemical odorant?

odorant binds to receptor

what happens in smell transduction after the odorant binds to the receptor?

secondary messenger system is activated

what does a calcium influx in smell transduction result in?

olfactory adaptation

what is olfactory adaptation?

decreased response to sustained stimulus

describe the adaptation/threshold of olfaction

low threshold, fast adaptation

what does low threshold for olfaction mean?

very small quantity required to perceive as an odor

what do olfactory nerves synapse with and where?

mitral cells in olfactory bulb

what do axons of mitral cells form?

olfactory tract

how do impulses from mitral cells travel to the olfactory cortex?

via olfactory tracts

where do impulses from mitral cells travel to?

the olfactory cortex in the temporal lobe

what is anosmia?

lack of olfaction

what is hyposmia?

reduced olfactory sensitivity

what can cause anosmia?

head injuries that damage neural pathways

what condition develops naturally with aging as fewer olfactory neurons are replaced by basal cells?

hyposmia

what is gustation?

sense of taste

where are gustatory receptors located?

in taste buds

where are taste buds located?

on papillae of tongue

what are the four types of papillae of the tongue?

fungiform, foliate, circumvallate, filiform

what papillae of the tongue is mushroom shaped and scattered over the tongues surface?

fungiform

what papillae of the tongue is located on the posterior sides of the tongue?

foliate

what papillae of the tongue is large, round, and forms a V on the posterior surface?

circumvallate/vallate

what papillae of the tongue is pointed, on the anterior 2/3, and has no taste buds.

filiform

where are most of the taste buds on tongue papillae found?

on tops of fungiform papillae and side walls of foliate and vallate papillae

where are few taste buds found?

soft palate, cheeks, pharynx, epiglottis

what is A?

foliate papillae

what is B?

vallate papillae

what is C?

fungiform and filiform papillae

what is D?

taste bud

what are gustatory epithelial cells?

taste receptors

what are gustatory hairs?

microvilli through taste pore

what makes up taste buds?

gustatory epithelial cells, gustatory hairs, basal epithelial cells, supporting cells

what is A?

connective tissue

what is B?

taste fibers of cranial nerve

what is C?

basal cells

what is D?

gustatory epithelial cells

what is E?

taste pore

what is F?

stratified squamous epithelium of tongue

what is G?

gustatory hair

what is H?

supporting cells

what are the five basic taste sensations?

sweet, sour, salty, bitter, umami

what makes things sour?

H+ ions in solution

what makes things salty?

metal ions (inorganic salts)

what makes things bitter?

nitrogen compounds

what makes something umami?

amino acids

what is the first step in taste transduction?

chemicals in food dissolve in saliva

what happens in taste transduction after chemicals in food dissolve in saliva?

chemicals come in contact with gustatory hairs through taste pores

what happens in taste transduction after chemicals come in contact with gustatory hairs through taste pores?

chemicals bind to receptor on hair cells

what happens in taste transduction after chemicals bind to receptors on hair cells?

cation channels open

what happens in taste transduction after cation channels open?

neurotransmitters initiate a graded potential in sensory neurons associated with receptor cells

what does taste trigger?

reflexes involved in digestion

what does taste increase?

secretion of saliva into mouth, and gastric juice into stomach

what are the protective reactions of taste?

gagging, reflexive vomitting

what sense is heavily associated with taste?

smell (olfaction)

what type of receptors influence taste?

thermoreceptors, mechanoreceptors, and nociceptors

what cranial nerves carry impulses from taste buds to the solitary nucleus of medulla?

Facial VII, Glossopharyngeal IX, and Vagus X

where is the gustatory cortex found?

in the insula

what allows for the emotional appreciation of taste?

hypothalamus and limbic system

describe the adaptation and thresholds for gustation

rapid adaptation, variation in thresholds

what are the thresholds in order of lowest to highest in gustation?

bitter, sour and umami, sweet and salty