The Chemical Senses

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  • Created by: jessica
  • Created on: 18-12-12 16:30
What are the chemical senses?
Gustation (taste) and Olfaction (smell)
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What are the five basic tastes?
Saltiness, Sourness, Sweetness, Bitterness, Umami
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What are papillae?
Small projections scattered on the tongues surface with smaller ones at the front and sides and larger ones at the back.
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What do paillae contain?
Taste buds which have taste receptor cells.
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What is the structure of the taste receptor cell?
Has the chemically sensitive part near the apical end which has microvilli which project into the taste pore where the taste cell is exposed to mouth contents.
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What must the salt concentration be for it to generate an action potential?
Above 10 mM
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How does sourness affect taste receptors?
Causes H+ to permeate the amiloride-sodium channel causing an inward H+ current, deolarizing the cell or the H+ binds to and blocks the K+ selective channels, depolarizing the membrane.
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What are bitter receptors good for?
Detecting poisons.
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What do sweet and bitter receptors have in common?
They both use G protein coupled receptors, but the sweet have 2 tightly bound proteins but bitter only has one.
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What is the central taste pathway?
3 cranial nerves carrying the primary gustatory axons, different parts of the tongue send axons to different cranial nerves.
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Which cranial nerve does the anterior part of the tongue send its axons to?
The facial nerve
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Which cranial nerve does the posterior part of the tongue send its axons to?
The glossopharyngeal nerve
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The axons sent to the vagus nerve come from where in the taste system?
The epiglottis, glottis, pharynx
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What is ageusia?
The loss of taste perception
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What is the Olfactory Epithelium?
A small thin sheet in the nasal cavity that is used to smell with.
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What is mucus?
A water based with dissolved mucopolysaccharides, various proteins containing antibodies, enzymes and odorant binding proteins and salts.
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What do odurant binding proteins do?
Help concentrate odorants in the mucus.
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What are olfactory receptor neurons like?
Have a single long thin dendrite, with a small knob at the end that has multiple cillia where odurants bind to, activating the transduction process.
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What is anosmia?
The inability to smell
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Why would the Olfactory response terminate?
Odurants diffuse away, broken down in the mucus, cAMP in receptor cell may activate other signalling pathways ending the transduction process.
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What is the Central Olfactory Pathway?
The Olfactory receptor neurons send axons into 2 olfactory bulbs
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What are the olfactory bulbs?
The input layer contains 2000 glomeruli with the endings of 25,000 primary olfactory axons within each glomerulus. These converge and terminate on dendrites of 100 second order olfactory neurons.
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What is the mapping of receptor cells on the glomeruli like?
Very precise with each glomerulus receiving specific receptor axons from particular regions of the olfactory epithelium.
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What is a sensory map?
An orderly arrangement of neurons correlating with certain features of the environment
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What role does temporal coding have on olfaction?
It is dependant on the timing of the spikes and encodes the quality of odors.
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Other cards in this set

Card 2

Front

What are the five basic tastes?

Back

Saltiness, Sourness, Sweetness, Bitterness, Umami

Card 3

Front

What are papillae?

Back

Preview of the front of card 3

Card 4

Front

What do paillae contain?

Back

Preview of the front of card 4

Card 5

Front

What is the structure of the taste receptor cell?

Back

Preview of the front of card 5
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