Module 2 - Taste Flashcards
(61 cards)
What are taste buds?
Clusters of taste receptor cells located mainly on the tongue that detect taste stimuli.
Where are taste receptors primarily located?
On the tongue, but also on the soft palate, epiglottis, and upper esophagus.
What is the name of the small structures on the tongue that contain taste buds?
Papillae.
What are the three types of papillae that contain taste buds?
Fungiform, foliate, and circumvallate papillae.
What type of cell within taste buds actually detects tastants?
Taste receptor cells (also called gustatory cells).
How long is the average lifespan of a taste receptor cell?
About 10–14 days.
What is the role of type II (receptor) taste cells?
They detect sweet, umami, and bitter compounds via G-protein coupled receptors.
What type of receptors detect salty and sour tastes?
A: Ion channels: ENaC for salty and H⁺-sensitive channels for sour.
What is the role of the G-protein gustducin in taste?
It transduces signals from sweet, umami, and bitter tastants in type II cells.
How are taste signals transmitted to the brain?
Via cranial nerves VII (facial), IX (glossopharyngeal), and X (vagus).
What are the five basic taste qualities?
Sweet, salty, sour, bitter, and umami.
Which taste receptor types detect sweet, umami, and bitter?
G-protein coupled receptors (GPCRs).
Which taste receptor types detect salty and sour?
Ion channels.
What receptors are involved in detecting bitter compounds?
T2R receptors (a family of ~25 different receptors in humans).
Which ion channel is mainly responsible for detecting salty taste?
Epithelial sodium channel (ENaC).
Which ion channel is mainly responsible for detecting sour taste?
Proton-sensitive channels, such as PKD2L1.
How do G-protein coupled receptors contribute to taste signaling?
They activate intracellular signaling cascades (e.g., via gustducin) leading to neurotransmitter release.
Why are there so many types of bitter receptors (T2Rs)?
To detect a wide variety of potentially toxic or harmful bitter compounds.
What makes salty and sour tastes different in their mechanism from other tastes?
They involve direct ion flow through channels, rather than receptor-mediated signaling.
How is taste perception modulated by other factors like temperature and texture?
These factors influence taste intensity and perception via sensory integration beyond just receptor activation
Where are the trans-membrane proteins for salt receptors located?
In the membrane of microvilli that are in contact with saliva.
What creates the membrane potential in salt receptor cells?
The difference in concentrations of Na⁺, K⁺, and Cl⁻ ions between the inside and outside of the cell.
What is the resting membrane potential of salt receptor cells and why?
Slightly negative, mainly due to a high concentration of Na⁺ ions outside the cell.
How do Na⁺ ions enter salt receptor cells?
Through always-open Na⁺ ion channels via passive diffusion.