taste and smell lecture and lab Flashcards
what are the special ions for salty and sour?
Na+ and H+
what type of cell is an olfactory receptor?
bipolar
filiform papilla
Where do the nerve impulses from the gustatory receptors go?
medulla oblongata (gustatory nucleus), thalamus, hypothalamus, insula, and limbic system. Travel to the brain via the facial, glossopharyngeal, and vagus nerve.
function of olfactory supporting cells
physical support, nourishment, electrical insulation, and help detoxify chemicals
what is the function of the orbitofrontal area?
odor identification and discrimination
where are the sour regions of the tongue?
sides of the tongue
why do smells and taste evoke emotional responses?
impulses for smell and taste propogate to the limbic system
vallate papillae
define foliate papillae
have taste buds, along the sides of the tongue but degenerate in early childhood
where are taste receptors located?
tongue, soft palate, pharynx, and epiglottis
where are the bitter taste buds located?
back of the tongue
What are the 5 primary tastes?
sour, sweet, bitter, salt, and umami
where is the umami region of the tongue?
center
define fungiform papillae
have taste buds, mushroom shaped elevations across the entire tongue
what are olfactory hairs and what do they do
they are cilia that project from the olfactory receptor’s dendrite and they respond to the inhaled chemicals
what type of receptors are olfactory receptors?
metabotropic
which cranial nerves are involved in gustation and what do they innervate?
facial- anterior 2/3 of tongue
glossopharyngeal- posterior 1/3 tongue
vagus-pharyx
olfactory epithelium and olfactory mucosa
what is adaption in terms of olfaction?
decreasing sensitivity to odors rapidly (takes seconds)
how long does gustatory adaptation take?
1-5 minutes
foliate papillae
define filiform papillae
no taste buds but has tactile receptors, cover the entire of the tongue, increase friction to move food easier
How do sweet, bitter, and umami receptors cause depolarization?
metabotropic, receptors attached to G proteins which activate secondary messengers which cause depolarization
what must happen to molecules for receptors to sense the sensation?
molecules must be dissolved before the taste or smell can be sensed
what are gustatory basal cells?
stem cells which produce supporting cells which then turn into gustatory receptor cells
what is transduction?
the conversion of stimulus energy into a graded potential in a sensory receptor
what are olfactory/bowman’s cells
they produce mucus which moistens the surface of the olfactory epithelium and dissolves odorants so that transduction can occur
define vallate papillae
have taste buds, 12 very large ones on the tongue, located in a V shape at the back of the tongue
where is the salt area of the tongue?
right behind the tip
Where do the impulses from the olfactory receptors go?
olfactory bulb, temporal lobe, limbic system, hypothalamus, orbitofrontal area
fungiform papillae
how long do gustatory receptor cells live?
10 days
vallate papillae
define the supporting cells of olfaction
columnar epithelial cells of the mucous membrane of the lining of the nose.
foliate papillae
where are the olfactory receptors located?
olfactory endothelium in the superior nasal cavity
what is the function of papillae?
increase surface area and provide rough texture
what are olfactory basal cells?
stem cells
what is the location of taste transduction?
gustatory hairs
Around what age are smell and taste gradually lost?
50
what type of sense are smell and taste?
chemical senses
what happens when olfactory receptors respond to the chemical stimulation of an odorant?
produce generator potential
where is the sweet area of the tongue?
the tip
which cranial nerve innervates supporting cells and olfactory glands?
facial nerve 7, autonomic
also stimulate lacrimal glands and nasal mucous glands
where do the axons of the olfactory receptors go?
through the olfactory foramina of the cribriform plate
what dissolves tastants?
saliva
