Chemical Senses Flashcards
Olfactory Epithelium
- 5 cmsq in superior part of nasal mucosa
- Pseudostratified epithelium
whats unique about olfactory neurons
unique among sense systems that are regularly replaced (30-60 days) and can regenrate after injuy
Olfactory neurons are:
They are bipolar
Have cilia w/in mucosa
Basal Stem cells do what
give rise to new neurons
What two types of cells/glands Secreate mucus for protection
Bowmans glands
Supporting cells
Odorant receptor types
GPCR, lots of types, on olfactory neuron cilia
Each neuron express _____type of odorant receptor: very specific but there are ______
1
thousands of them
- Ligand (odorant) binds to receptor in pocket
pocket made by
7 transmemb regions from the GPCR
Ligand regions are:
Highly varialb aa sequence in transmembrane region
→ possible mechanism for recongtion of so many dif ligands
odorant binds to odorant receptor we get→
depolarization
olfactory neurons projected→ through
crib plate to olfact bulb→ synapse onto neurons in clusters called glomeruli
neurons in clusters called (olfactory bulb)
glomeruli
W/in each glomerulus are
a. mitral cells
b. tufted relay cells
c. periglomuler interneurons
olfactor receptors for same ligand will all end up sending their axons to the same glomerulus that is attached to a
mitral cell
Results in spatial map so there may be processing occuring in the olfactory bulb
convergence
In olfactory cortex: Mitral and tufted cells (in the bulb) receive info from the olfactory neurons – > sending info to
back along the olfactory tract there are several possibilities of where they can end up
projections to contralateral olfactory bulb and all othres go ipsilaterally
Anterior commisure
Olfactory Tract is made up of:
axons of mitral and tufted cells from olfactory bulb
MOST olfactory neurons go to
to Entorhinal cortex→ thalamus or hippocampus
Projections go here for emotional aspect of smell (memories)
some to amygdala (limbic)
projections to______ is emotional and motivation of smell
hippocampus
Why so we send olfactory info to thalamus?
Direct attention to stimulus
Projection to hypothalamus for:
- physiological aspectes of smell
-direct attention to stimulus
-perception and discrimination of odors
~oatmeal or ch. chip cookie
thalamus
gustatory sense + olfacory sense + general sensation =
Flavor
gustatory sensation=
Taste
taste receptors =
epithelial cells (not neurons like in nose)
stem cells for turnover in taste buds
basal cells
_______ extend into taste pore and saliva is here with molecules
Microvilli
At_____ of taste bud Sensory neurons contact taste receptos
base
Location of taste buds on Tongue (ant 2/3 )
Nerves that transmit taste sensation:
Location of sensory neuron cell body:
Ends in:
Facial N VII via chorda tympani
Geniculate ganglion
Rostral nueclues Solitarius or Gustatory gang
Location of taste buds on Posterior 1/3 tongue
Nerves that transmit taste sensation:
Location of sensory neuron cell body:
Ends in:
Glosspophyarngyeal IX
Inferior ganglion
Rostal nucleus or Solitarius or Gustatory gang
Location of taste buds on palate
Nerves that transmit taste sensation:
Location of sensory neuron cell body:
Ends in:
Facial VII via greater petrosal n.
Geniculate gang
Rostal nucleus or Solitarius or Gustatory gang
Location of taste buds on epiglottis
Nerves that transmit taste sensation:
Location of sensory neuron cell body:
Ends in:
Vagus via superior larnygeal n’s internal laryngeal branch
Inferior gang
Rostal nucleus or Solitarius or Gustatory gang
Gustatory ganglion→ Then goes to_____ of thalamus→ to ________ (where taste cortex is located)
VPM
anterior region of insula
Where do we go from anterior region of insula
superior/inferior salivatory nucleus or amygdala