Chemical Senses Flashcards
What do small positively charged things taste like?
Bitter
What 4 things encode taste or are important to taste?
Pattern of neural activation
Smell
Other perceptual elements like temperature
Texture
What are the two chemical senses and what type of receptors do they have?
gustation and olfaction have chemoreceptors
Give the hierarchy of structures in taste (ie different cell/structure types)
Tongue
Papillae
Taste bud
Taste cells
What are the components of a taste bud?
Microvilii project into the taste pore and then an orange like array of taste cells surrounds. Basal cells are at the end of the taste bud and provide support
Where are the four basic tastes tastable?
All over the tongue.
How can you only stimulate certain parts of the tongue with a taste?
By using very very low concentrations of it
Describe the papillae
Bathed in fluid, the papillae are covered in taste buds (hundreds per papillae, 2000-5000 a person). Each papillae has a taste that it is maximally sensitive to
How many taste buds are in people (n practice)
Range from 500 to 20000, though most say 2000-5000
How long does it take for taste cells to turnover?
Every two weeks
What are axons from taste cells called?
Gustatory afferent axons
Are taste cells capable of having action potentials? What type of potentials do they have?
They can produce action potentials after building up a large enough receptor potential
How many tastes can a taste cell detect?
Taste cells can detect 1 or more tastes, though usually more than one.
What are the sodium channels of salty taste receptor cells like?
They are not voltage gated and they are always open at rest. Depolarization from sodium influx causes calcium to enter the cell and cause neurotransmitter release in an action potential
What are sour taste cell receptor channels like? How do sour tastes give a double whammy depolarization?
Same as the salty sodium ones, except they let protons and high energy anions in. Protons can block potassium channels, preventing it form leaving the cell and causing an even greater depolarization
What three tastes use a G protein coupled receptor? What is the effector protein in these pathways called?
Sweet, bitter and umami have G protein coupled receptors.
The effector protein for these G proteins is called phospholipase C