Chapter 4 - The Chemosensory System: Taste and Smell Flashcards
olfactory system
chemosensory system that deals with the detection of ariborn chemicals and which produces the perceptual impressions of smell
gustatory system
chemosensory system that deals with the detection of dissolved chemicals and that produces the perceptual impression of taste
pheromones
chemical substance emitted by specialized glands in many animals to attract mates, singal sexual receptivity, or affect the behaviour of othe memebers of the same species
vomeronasal organ (VNO)
paired chemosensory organ located in the nasal cavities of many terrestrial species. Also known as Jacobson’s organ, the VNO appears to be the primary sensory system for the detection of pheromones
umami
taste common to diverse foods such as fish, meats, cheese, and some vegetables. Corresponding words in English are savoury, brothy, and meaty
taste buds
specialized pear-shaped sensory structure found primarily in the skin of the tongue. Taste buds contain the cells that are responsible for genrating taste signals in response to chemicals dissovled in the saliva
papilla (include types)
small mounds of tissue found of the surface of the tongue. The term is derived from the Latin word for the niple of the mammary gland. . Includes: Filiform, fungiform, foliate, circumvallate
tastants
chemical stimuli derived from foods that are dissolved in saliva and which produce electrical signals in taste buds
microvilli
small folds in the membrane of receptor cells where testant binding occurs
facial, glossopharyngeal, and vagus nerves
cranial nerves VII, IX, and X, respectively. These nerves, expecially VII and IX, carry gustatory signals to the brain
second messenger
specific chemical substance that is involved in the transduction cascade within cells
labelled-line coding
notion that sensory neurons are selective to only a specific type of stimulus. In the gustatory system, this hypothesis asserts that taste neurons are selective to only one of the taste primaries
cross-fibre coding
notion that sensory neurons are triggered by a broad range of stimuli. In the gustatory system, this hypothesis asserts that taste neurons can be stimulated by multiple taste primaries
chemotopic organization
organized representation of different taste primaries in the gustatory system
nucleus of the solitary tract (NST)
collection of neurons locted in the medulla of the brain sttem. A subset of the neurons here seves to relay taste signals to the thalamus
ventral posterior medial nucleus (VPMN)
small nucleus in the thalamus that serves as the second relay for taste signals. Neurons here send their axons to the primary gustatory cortex
insula
area of the cerebral cortex in the frontal lobe that is located within the Sylvian fissure. the insula are surrounding cortex together make up the primary gustatory cortex
glomerulus
confined spatial unit in the olfactory bulb where several thousand axons from olfactory sensory neurons converge. Each glomerulus is believed to act as a small functional module for processing olfactory information
concentration
a measure of the amount of dissolved substance per unit volume of a solution
electrogustometry
application of electrical current to the tongue through an electrode to determine taste function
chemogustometry
application of chemical solutions to the tongue to determine taste functions
hedonic
judgment of sensory quality in terms of positive or negative appreciation (like or dislike)
dysgeusia
distortion of taste sensation
adaptation
reduction in perceived intensity or sensitivity due to prior or ongoing background stimulation
