Nervous System 6 Flashcards
_____ are the peripheral organs of gustation
Taste Papillae
Taste papillae contain _____ which are the functional units of gustation
Taste buds
Are test receptors cells are epithelial cells or neurons?
Epithelial cells
_____ are chemicals that can activate a taste receptor cell
Tastants
T/F: All tastants must dissolve in saliva
True
T/F: Individual taste receptor cells may be sensitive to a specific taste stimulus, but many taste receptor cells have receptors for multiple taste types.
True
___ is vital for normal gustation
Olfaction
What 2 taste are ion channel linked receptors?
Sour and salty
What 3 tastes are accounted for by the taste receptor genes? (TR1 and TR2) (g-protein)
Sweet, bitter, and umami
Stimulated by H+, Protective taste b.Multiple candidate receptors a.Amiloride-sensitive epithelial Na+ channel (ENaC), H+ channels, blockade of K+ channels b.All potential mechanisms lead to depolarization of receptor cells
Sour taste
___ taste a.Lots of stimuli: sugars, glycols, alcohols, artificial sweeteners (saccharine, aspartame, sucralose)b.T1R receptor family is important. Specifically, T1R2 & T1R3 proteins make a dimer that is G-protein linked i.Broadly sensitive to sweet-tasting substances. ii.Sweet receptors are usually NOT on the same cells as bitter & umami.
Sweet Taste
____ taste a.Stimuli are usually organic: K+, denatonium, caffeine, strychnine, quinine, nicotine, broccoli, brussel sprouts b.Protective taste: highest number of receptors and lowest threshold for perception c.Multiple Receptors (50-80) in T2R family
Bitter Taste
____ salts are colorless and odorless solids that are used to prevent inappropriate ingestion
Denatonium salts
____ taste a.Stimulated mostly by Na+ and somewhat by Cl- b.Receptor: i.ENaC (Na+ channel) ii.Cl- via paracellular transport?
Salty.
___ taste Stimulus: monosodium glutamate, enhanced by ribonucleotides b.Receptor: i.Metabotropic glutamate receptor (mGLuR4 receptor)
Umami
Which taste tends to have lowest threshold?
Bitter
Taste specificity is best at ____ ligand concentrations
low
Does Taste does not solely depend on combinations of the aforementioned 5 receptors?
No
If a person is a supertaster, that do they have an increased amount of?
Fungiform papilla and taste buds
Are supertasters more or less responsive to other tastant types than a normal taster?
More
Where do taste receptors synapse?
First order neurons
Where are the second order neurons for taste?
Nucleus tractus solitarii
The _____ is a purely sensory nucleus in the medulla and it receives input for taste, chemoreceptors, aortic bodies, etc.
Nucleus tractus solitarii (NTS)
T/F: Olfactory cells are primary afferent neurons
True
Olfactory Receptor cells are _____ neurons that have a short peripheral process that extends into the mucosa where it ends in an expended olfactory knob. The knob gives rise to several cilia that form a dense mat at the mucosal surface. The cilia interact with odorants in mucus
bipolar
New receptor cells generated every ____ days from basal cells and they must form synapses with ____ cells in the olfactory bulb.
60 days; mitral cells
_____ are globular structures in the olfactory bulbs and it is where the short axons from olfactory receptor cells terminate. Each one is the terminus for ~25,000 axons and dendrites from mitral cells.
Glomeruli
Where do axons of olfactory receptor cells synapse with mitral cells?
Olfactory bulb
Is AP frequency of olfactory receptor cells more or less?
More
What Is the resting membrane potential of olfactory cells
-55mV
Do olfactory receptor cells with one type of odorant receptor project to a single or multiple glomeruli?
One
What G coupled protein receptor is used in olfaction?
Adenylyl cyclase
Increased levels of _____ open sodium channels to depolarize the olfactory neuron
cAMP
To be perceived, odorants must be ____, be _____, be _____, and reach _____
Be volatile, be partially water-soluble, be partially lipid-soluble, and reach olfactory mucosa
How much of adaptation of olfaction is achieved in the first second?
50%
____ are the special inhibitory cells in the olfactory bulb
Granule cells
T/F: Different olfactory receptor proteins respond differently to the same odorants
True
Information conveyed by relative amount of activity across multiple, differentially sensitive elements in an array.
Across-Fiber Pattern Code
The olfactory tract enters the brain at the junction between the _____ and the _____ and divides into two pathways.
midbrain and the cerebrum
The medial olfactory pathway goes to _____ and ______ for olfactory reflexes
hypothalamus and limbic system
The _____ olfactory area deal with Automatic but learned control of food intake and aversion to toxic and unhealthy foods and Conscious perception and analysis of olfaction.
Lateral olfactory area
___ means can’t identify taste
Taste agnosia
____ means loss of taste
Ageusia
____ disorders are frequently with aging; may be better predictor of Alzheimer’s;
Olfactory disorders
