PHYS: Olfaction + Gustation Flashcards
Umami senses?
Glutamate
Bitter senses?
Posions!
Coffee
What happens when a taste cell gets activated?
It depolarizes
Sour + salty trigger what?
A calcium-triggered release of seratonin
Sweet, bitter, + umami (SUB) trigger what?
calcium-triggered release of ATP
Salty opens up _______ channel to secrete ______.
Salty = Epithelial Na+ Channel (ENaC)
releases 5-HT (seratonin)
Sour is evoked by _____ and causes a ______ release.
Sour = evoked by H+ (acidic)
releases seratonin
Sweet, Umami, and Bitter use what type of channel to increase Ca+ leading to depolarization and secretion of ATP?
GPCR
What specific GPCR does umami use?
mGluR4
Why do GPCRs have such high binding affinity?
bitter stuff is usually poison, so it binds with high affinity to save you from eating posionous stuff (evolutionarily helpful)
What innervates taste buds?
Where do they terminate?
Special visceral afferent neurons
Terminate in the nucleus solitarius (gustatory area)
We know that CN 7 innervates the ant. tongue, but what get the rest of it + the epiglottis?
Post. tongue = 9
Epiglottis = 10
7 =
9=
10 =
7 = geniculate ganglia
9 = petrosal ganglia
10 = nodose ganglia
What makes up the “gustatory cortex”?
Just the purple
Postcentral gyrus
Frontal operculum
Insula
What is the pathway for ascending taste?
Nucleus tractus solitarius –> VPM –> post. limb of IC –> terminate in postcentral gyrus, frontal operculum, insular cortex
What is responsible for hunger? (mechanism of eating)
Hypothalamus
What is responsible for discrimitive aspects of taste?
VPM of thalamus
What integrates visual, somatosensory, olfaction, and gustatory stimuli?
Gustaory cortex
What is responsible for the emotional aspect of eating + memories of eating?
Amygdala
What preforms the medullary reflex arcs that allow us to swallow + salivate?
Nucleus tractus solitarius
What is the function of the Golf receptor? (listen to lecture)
On odorant stimulates it
Golf stimulates –>
Adenylyl cyclase –> increases cAMP –> opens CNGC (cyclic nucleotide gated channels)
And if an odor persists then CGNC = desensitized or inactivated. It allows you to adapt or “get used to” a smell, so that you don’t notice it anymore.
A high concentration of an odor smells like poop.
concentration matters
What cells are found in the olfactory bulb?
Mitral cells, granule cells, periglomerular cells
Which cells release GABA?
Granular + Perislomerular (interneurons)
What do olfactory neurons release?
Glutamate
What is the only sensory system that does not route through the thalamus before connecting to the cortex?
Olfactory (smell)
What is the function of the anterior olfactory nucleus?
Relay station to the cortices
The piriform cortex —> lateral hypothalamus functions in?
Control of appetite/hunger
Piriform cortex –> thalamus –> medial orbitofrontal cortex functions to?
Integrate taste, sight, and smell
Appriciate food
The anterior cortical amygdaloid nucleus functions in?
emotional learning
olfactory fear conditioning
The periamygdaloid cortex functions in?
Emotional aspect of an odor
(like when I smell dead bird)
Lateral entorhinal cortex —> hippocampus
Important in memory formation + recall
Are taste receptors neurons?
no they are modified epithelia cells w/:
- Fixed permeability (stay open @ rest)
- Shifting Na+ gradient
How do you describe olfactory receptors?
They are neurons:
- Fixed Na+ gradient
- Shifting permeability
To get “flavor” what 3 things do you need input from?
- Gustatory cortex
- Olfactory cortex
- Somatosensory from mouth
MEDIAL ORBITOFRONTAL CORTEX
When you get a cold and thickened mucus blocks odorants from binding, what is this called?
Reversible hyposmia
Why is smell strongly correlated w/ memory?
Because, the hippocampus + amygdala = limbic system —> mood + emotions
They associate an emotional response w/ odors. Thats why if you had a traumatic experience and smell something like it it will bring you back. They also allow for memories after the odor stops.
