Chemical Senses (9) Flashcards
What senses combine to create flavor?
smell taste, orosomatosensory
What is the pathway for olfactory processing?
- olfactor receptors via CN I to olfactory bulb
- bulbar neurons via lateral olfactory tract to piriform cortex at tip of temporal lobe
3a. to parts of neocortex via mediodorsal nucleus of thalamus
3b. lateral hypothalamus
What is the lifespan of a sensory neuron?
about 30 days
Describe a typical olfactory receptor in the olfactory epithelium and the pathway
7 transmembrane domains
G protein coupled
inc in cAMP –> activation of adenylyl cyclase
depolarization and increase of ca2+
What determines the physiological responsiveness of an olfactory neuron?
type of OR it expresses
What are the layers of laminar organization in the olfactory bulb?
- glomerular layer
- external plexiform layer
- mitral cell layer
- granule cell layer
Which cells of the bulb project to the olfactory cortex?
mitral and tufted cells
Which cells of the bulb inhibit mitral tufted cells?
periglomerular and granule cells
How would you describe the projection of the sensory surface onto its central structures?
not point to point but quadrant to quadrant onto a specific set of glomeruli
one OR, one glomerulus
Each gustatory axon is innervated by how many taste buds?
2-10
CN VII receives taste bud information from where? What are the branches?
taste buds on anterior 2/3 of the tongue
chorda tympani nerve to the tongue
greater superficial petrosal to the palate
CNIX receives information from where?
taste buds on the posterior 1/3 of the tongue
CNX receives information from where?
taste buds on the epiglottis
Describe the basic taste pathways?
-CN VII, IX, X send to solitary nucleus of brainstem
- NTS to VPM of thalamus
- NTS also to hypothalamus and amygdala
-VPM, hypothalmus, amygdala to insula & frontal cortex
Where are the circumvallate taste buds located and what do they sense?
posterior tongue
most sensitive to bitter
