Chapter 9_Chemical Senses Flashcards
Olfaction
The sense of smell, which detects volatile chemicals (odorants) in the air, allowing organisms to identify and respond to environmental stimuli.
Odorants
Chemical compounds that activate the olfactory system by binding to specific olfactory receptors.
Olfactory Epithelium
A mucus-covered tissue located in the nasal cavity that contains olfactory receptor neurons responsible for detecting odorants.
Olfactory Receptor Neurons (ORNs)
Sensory neurons in the olfactory epithelium that detect odorants and send signals to the brain. These neurons are the only type exposed to the outside environment.
Olfactory Bulb
A brain structure that receives input from olfactory receptor neurons and processes olfactory information before sending it to higher brain regions.
Glomerulus
Structures within the olfactory bulb where the axons of olfactory receptor neurons converge and synapse with mitral and tufted cells, responsible for the initial processing of olfactory signals.
Mitral Cells
Secondary neurons in the olfactory bulb that relay olfactory signals from the glomeruli to the olfactory cortex.
Piriform Cortex
The main region of the olfactory cortex responsible for processing olfactory information and integrating it with other sensory inputs.
Gustation
The sense of taste, which detects flavorants (chemical compounds in food) through taste receptors located primarily on the tongue.
Flavorants
Chemical compounds that activate taste receptors, contributing to the perception of taste.
Taste Buds
Sensory structures located on the tongue and other parts of the oral cavity that contain taste receptor cells responsible for detecting taste stimuli.
Taste Receptor Cells
Specialized epithelial cells within taste buds that detect the five basic taste modalities: salty, sweet, sour, bitter, and umami.
Salty Taste
Mediated by sodium ions (Na+), which pass through epithelial sodium channels (ENaCs) in the taste receptor cells, leading to depolarization and neurotransmitter release.
Sour Taste
Mediated by proton (H+) channels, which respond to acidic foods, leading to depolarization of taste receptor cells.
Sweet Taste
Mediated by G-protein-coupled receptors (T1R2/T1R3) that respond to sugars and sweeteners, triggering signaling cascades that lead to taste perception.