W1D1 - Neuro - Olfactory And Gustatory Systems

Front 1

What cells detect odors?

Back 1

Chemoreceptors - best stimulated by chemicals dissolved in liquid rapid acccommodation/adaptation
Specifically: olfactory receptor cells present in the top 1/3 of the nasal cavity - their axons compose the filia olfactoria which passes through the cribiform plate of the ethmoid bone and synapses in the olfactory bulb on mitral cells - they are the true first cranial nerve - CN I

Front 2

How can the olfactory receptor cells be damaged following head trauma?

Back 2

Because the cells axons are flowing through the cribiform plate of the ethmoid bone, head trauma may cause the plate to break and thus sever the axons - not to worry though - the cells will be replaced monthly so (asnomia) won't last too long :)

Front 3

Fibers of what neurons make up the olfactory/tract/nerve?

Back 3

Mitral axons

Front 4

Where do the mitral axons/olfactory tract project to? Describe pathways.

Back 4

PRIMARY OLFACTORY CORTEX: located in the piriform lobe; uncus periamygdaloid cortex, and anterior entorhinal cortex - (although in class he said the primary olfact. cortex consists of piriform cortex + periamygdaloid cortex - piriform cortex overlies the uncus)
They then can send the message on to the posterior orbitofrontal cortex via mediodorsal nucleus of thalamus - likely this is the appreciation of smell

Front 5

T/F an overlapping mechanism is seen within the nose thus 'encodes' the smell.

Back 5

true

Front 6

What is the olfactory tract an extension of? Is it 'really' a nerve?

Back 6

It is an ext. of telencephalon - part of brain - not nerve

Front 7

Each of the olfactory neurons (CN I) have protein receptors that bind chemicals - how many different ones?

Back 7

50

Front 8

What cell is the secondary afferent when speaking of olfaction

Back 8

mitral cell

Front 9

T/F there are granule cells present in the olfactory bulb.

Back 9

true

Front 10

T/F Smells hurt.

Back 10

smells don't hurt, it's the activiation of the trigeminal n. - becuase there are other sensory ending (from trigeminal) -gives you touch (localized) when you smell something that hurts...it initiates sneezing

Front 11

At what age does smell peak?

Back 11

40-50 years old

Front 12

We have an innate ability to react to pain, so if smell initiates pain -

Back 12

we learn

Front 13

T/F there are cell bodies found ALL along the olfactory tract.

Back 13

true

Front 14

T/F the orbitofrontal cortex can shut down smell if smell isn't useful.

Back 14

true

Front 15

T/F Humans do have input to amygdala and fetus have vomeronasal organ, but later disappears.

Back 15

true

Front 16

Where is the olfactory cortex?

Back 16

located in piriform lobe: uncus, periamygdaloid cortex, anterior entorhinal cortex; then projects to posterior orbitofrontal cortex via mediodorsal nucleus of thalamus - likely location of apprecation of smell.

Front 17

Where is the gustatory cortex?

Back 17

located completely beneath the cortical surface along the insula - in frontal lobe it is in the operculum

Front 18

What nerves carry taste?

Back 18

CN VII, IX, AND X

Front 19

Where is taste conveyed?

Back 19

first: nucleus of the solitary tract (cranial most portion) -> ventral posterior medial nucleus of the thalamus -> primary gustatory cortex and operculum -

Front 20

T/F the taste message is somatitopically organized it's entire length?

Back 20

true

Front 21

How is gustatory sense created?

Back 21

by taste bud stimulation

Front 22

How many tastes buds are found within a papillae on the tongue?

Back 22

5.000

Front 23

What tastes does the glossopharyngeal nerve project/receive from the tongue and from what area of the tongue?

Back 23

sour and bitter - posterior 1/3 tongue and pharynx

Front 24

What tastes and what area of the tongue is the facial n. responsible for?

Back 24

sweet and salty - anterior 2/3

Front 25

What does CN 10 carry and from waht area?

Back 25

has some taste from the epiglottis - all taste is bitter though - this gives you that 'throw- up reflex'

Front 26

Taste buds are only one aspect of the integrated sensation, what else comprise the taste sensation?

Back 26

stimulation of OLFactory receptors
stimulation of 'other' chemical and somatosensory receptors -from trigeminal nerve - (texture, temperature, spiciness (pain: peppers, menthol), pungency)
stimulation of other special receptors: vision and hearing

Front 27

It is stated that certain areas of the tongue are more associated with paticular tastes. explain.

Back 27

the tip of the tongue: sweet
sides of the tongue: salty and sour
along the terminal sulcus and posterior: bitter

Front 28

What tastes are there?

Back 28

Sweet
Salty
Sour
Bitter - warning: to get it out of your mouth - vagus sends signal = gag reflex

Glutatmate - umami

Front 29

How is the olfactory and gustatory system similar?

Back 29

they both respond to concentrations of stimuli (chemicals)

Front 30

What is a taste bud comprised of?

Back 30

contains 50-100 epithelial cells:
3 major types: supporting cel, gustatory cells, basal cells - they containt long microvilli - extends through the taste pore.

Front 31

What neurons leave the taste bud from the gustatory receptor cell?

Back 31

the primary afferent of VII, IX, and X - similar to neruons, but are not neurons themselves (the gustatory recpetor cells) they are dervied from epithelial cells.

Front 32

What ganglion is associated with CN VII and taste?

Back 32

Geniculate ganglion - they are conveyed via the chorda tympani

Front 33

What ganglia are assocatied with the CN IX AND X and taste?

Back 33

Inferior ganglion

Front 34

The insular cortex projects to the _

Back 34

orbitofrontal cortex

Front 35

T/F both insular and orbitofrontal are part of the limbic system.

Back 35

true - the limbic system is responsible for the behavioral and emotional significance of taste

Front 36

What is the Labeled line model?

Back 36

suggests that different tastes have segregated pathways to the brain - one scent - one receptor - one pathway

Front 37

What is the Across Fiber Theory?

Back 37

different tastes are represented by diffrent activity across a neural population - mainly works THIS way - all interconnected.

Front 38

T/F gustatory sense is a small component of flavor - so much more involved.

Back 38

true - very complex - there is much we still don't know

Front 39

Do we think that the gustatory system works via labeled line theory or across fiber theory?

Back 39

across fiber

Front 40

SO, where does all in the information end up in gustatory sense?

Back 40

Orbitofrontal cortex - anterior portion of cingulate gyrus -> amygdala+limbic -> hypothalamus -> ANS -> heart rate inc. and eyes dilate, and you salivate when experience food.

Front 41

What is the tongue?

Back 41

a mass of skeletal muscule with a MEDIAN septum divding it into left and right halves

Front 42

What are the functions of the tongue?

Back 42

taste, mastication, swallowing and speech

Front 43

What is the tongue anchored by?

Back 43

styloid process, hyoid bone, mandible, and pharynx - generally divided into an oral part and pharyngeal part.

Front 44

What is the oral part of the tongue?

Back 44

divided into an anterior 2/3 and post. 1/3 by a V-shaped groove -the terminal sulcus: embryological remnante of the junction between pharyngeal arch 1 and 3 -

Front 45

what is the median pit of the at the apex of the terminal sulcus?

Back 45

foramen cecum: marks the opening of the thyroglossal duct: the spot from which teh thyroid gland descended as an ipithelial invagination

Front 46

What types of papilla are found on the tongue?

Back 46

filform: most numerous, concentration on the dorsum
FOliate: leaf-like, located along te post. margin
fungiform - mainly on apex, with tast buds on lateral surfaces
vallate (circumvallate) - 3-14 in a row anterior to the terminal sulcus, with taste buds on lateral surfaces

Front 47

What comprises the pharyngeal part of the tongue?

Back 47

forms anterio boundary of oral pharynx
bummy surface from the lingual tonsil, no lingual papillae

Front 48

Taste is conveyed by what three cranial nerves?

Back 48

VII, IX, and X - fibers associated with CN VII are conveyed via the chorda tympani

Front 49

All taste is consolidated in the ______ nucleus and conveyed to the VPM of the thalamus

Back 49

solitary nucleus