Transcript Lecture
Taste & Smell Smell vs. Taste? • Nose • Mouth, & many places • Taste buds • Sensors in SCC the Olfactory Epithelium • Many uses, • Primarily for including feeding food location Water Flow Olfactory Epithelium Flaps direct water through the nares and over the olfactory epithelium Water Flow Flaps Smell not important Relies Heavily On Smell Molecules Whooshing by in the Water Nerves to the brain Olfactory Epithelium Ciliated Cells Every Odor Molecule is a Little Bit Different Molecule “ keys” fit in olfactory cell “locks” and the fish perceives the smell of red squares, yellow circles, and purple triangles. This fish can’t smell Nerves to the brain or . 0 50 0 50 • Amino acids: The building blocks of protein. Some amino acids are more stimulatory than others. • Steroids: Some fish are highly sensitive to hormones especially those related to reproductive activities – Prostaglandins: Hormones released by female fish upon ovulation. Amino acids at concentrations of 1 part in 200,000,000,000 steroid hormones at 1 in 30,000,000,000,000 1 in 200 billion = 6 mg/acre-ft 800,000,000,000,000 molecules/tsp 1 in 30 Trillion = 0.04mg/ acre ft 5,600,000,000 molecules/tsp Water Epidermis Dermis Taste Bud Nerve What Can They Taste ? What Can They Taste ? • • • • • • sweet, sour, bitter, salty, uma Amino acids Steroids: Sex hormones Organic acids and nucleotides: Carbon Dioxide: ?? Peptide toxins: Like marine puffer toxin Solitary Chemoreceptor Cells: SCC • Dispersed on external surface of fish as well as on gills and in the oral cavity. • These cells are sensitive to amino acids in some species but not others. • They are especially adept at detecting fish mucus and some organic acids. Rockling • 6 million SCC • dorsal fin • Prey detection Dorsal fin -Mucus and bile -Predator avoidance 100 per square millimeter on minnows and carp! Smell in Action Salmon Migration Yukon River 2,300 miles Yukon River Life Cycles • Eggs: found in a redd • Alevin: fry with yolk • Parr: Fingerlings in fresh water, black bars • Smolt: Fingerling ready for the sea, silver • Adult: In the sea Spawns and then dies Does not die, returns to the sea Alevin Alevin Parr Parr Parr Smolt Parr Imprinting Theory • Each stream has a unique chemical signature • Young salmon learn the smell of their river • Later as adults they home in on that smell and return home Imprinting Pheromone Theory • Young salmon live in the river for 2-5 years before migrating • Young salmon are genetically similar to the adult salmon in the sea • Young salmon release pheromones specific to their population • Mature salmon smell the young and find the stream Pheromone Homing Theories •Imprinting: Salmon smell the stream •Pheromone: Salmon smell their kin •Which is right? Stream Odorant Experiments Pheromone: Kin recognition Adult Ranges of Pacific Salmon S N QUIZ • Difference between taste and smell • Lock and Key • Functions of taste and smell • Salmon life cycle (egg, alevin, parr, smolt adult) • Salmon migration Smell •Nares and SSC •Lock and key Taste •Barbles, lips, mouth, skin •Mostly for food •Also lock and key • Safety – Fright Reaction – Toxin detection • Feeding Taste and Smell – Finding Food – Testing food • Reproduction – Kin recognition – Homing – Reproductive Hormones • Eggs: found in a redd • Alevin: fry with yolk • Parr: Fingerlings in fresh water, black bars • Smolt: Fingerling ready for the sea, silver • Adult: In the sea