chapter 8 Flashcards
(43 cards)
The FIVE Basics Tastes
Saltiness, sourness, sweetness, bitterness, and umami
Examples of correspondence between chemistry of taste
Sweet—sugars like fructose, sucrose, artificial sweeteners (saccharin and aspartame)
Bitter—ions like K+ and Mg2+, quinine, and caffeine
The Organs of Taste:
Tongue, mouth, palate, pharynx, and epiglottis
Mechanisms of Taste Transduction: Transduction PROCESS:
Taste stimuli (tastants):
Pass directly through ion channels
Bind to and block ion channels
Bind to G-protein-coupled receptors
Mechanisms of Taste Transduction: Saltiness (ion channel):
Salt-sensitive taste cells
Special Na+ selective channel
Blocked by the drug amiloride
Mechanisms of Taste Transduction: Sourness (ion channel)
Sourness- acidity – low pH
Protons causative agents of acidity and sourness
Mechanisms of Taste Transduction: Bitterness (G-protein couple receptor)
Families of taste receptor genes –TIR and T2R
Mechanisms of Taste Transduction: Sweetness (G-protein couple receptor)
Sweet tastants natural and artificial
Sweet receptors
T1R2+T1R3
Expressed in different taste cells
Mechanisms of Taste Transduction: Umami (G-protein couple receptor)
Umami receptors:
Detect amino acids (glutamate)
T1R1+T1R3
Central Taste Pathways
VII facial N
IX glossopharyngeal N
X Vagus N
What is the Cribriform plate
A thin sheet of bone through which small clusters of axons penetrate, coursing to the olfactory bulb
what is Anosmia
Inability to smell
Describe the mechanism by which taste stimuli are transduced in taste cells.
Taste stimuli are transduced in taste cells through various mechanisms, including passing directly through ion channels, binding to and blocking ion channels, or binding to G-protein-coupled receptors.
What is the significance of papillae in the perception of taste?
Papillae play a role in taste perception by housing taste buds, which contain taste receptor cells that detect various taste stimuli.
Explain the differences in taste receptor distribution on the tongue and their corresponding sensitivities.
Areas of sensitivity on the tongue include the tip (sweetness), the back (bitterness), and the sides (saltiness and sourness).
Discuss the mechanisms of taste transduction for saltiness, sourness, bitterness, sweetness, and umami.
Mechanisms of taste transduction include ion channels for saltiness and sourness, and G-protein-coupled receptors for bitterness, sweetness, and umami.
Identify the cranial nerves involved in taste sensation and their respective regions of innervation.
VII facial N, IX glossopharyngeal N, X Vagus N. These cranial nerves innervate different regions of the tongue and oral cavity.
Trace the central taste pathways from taste receptor cells to the cortex.
The central taste pathways involve synapses in the brainstem, then ascend through the thalamus to reach the cortex.
Describe the role of pheromones in olfaction and give examples of their importance in animal behavior.
Pheromones are chemical signals used in olfaction to communicate various signals such as reproductive behavior, territorial boundaries, identification, and aggression.
Explain the structure and function of the olfactory epithelium.
The olfactory epithelium contains olfactory receptor cells, supporting cells, and basal cells, and is responsible for detecting odorants.
What is anosmia, and what are some factors that may contribute to it?
Anosmia is the inability to smell, often caused by various factors such as injury, infection, or genetic conditions.
Discuss the neural pathways involved in olfactory processing, from the olfactory epithelium to the cortex.
Olfactory axons project through the cribriform plate to the olfactory bulb, then synapse in various brain regions, including the medial dorsal nucleus of the thalamus and the orbitofrontal cortex.
Compare and contrast the mechanisms of taste transduction for saltiness and sourness.
Saltiness is transduced through salt-sensitive taste cells with special Na+ selective channels, while sourness is transduced through sour-sensitive taste cells activated by acidity and low pH.
Discuss the role of the olfactory tubercle and the medial dorsal nucleus of the thalamus in olfactory processing.
The olfactory tubercle and medial dorsal nucleus of the thalamus are involved in olfactory processing, with the olfactory tubercle linking olfactory information to reward circuits, while the thalamus relays olfactory information to the orbitofrontal cortex for further processing.
