Biology of Fishes Lecture 1 - Lecture Sensory Systems Sensing the Environment o Need to detect food predators sound noxious stimuli sense

Biology of Fishes Lecture 1 - Lecture Sensory Systems...

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Lecture: 10/1/19Sensory SystemsSensing the EnvironmentoNeed to detect food, predators, sound, noxious stimuli, sense environment, etc.oEnvironmental Stimuli Sensory systems Nerve impulses Integrated Interpreted ActionProperties of WateroSound travels faster in wateroDense: 800 times denser than airoIncompressible: any particles that moves, moves the particle next to itoConducts electricity well (especially marine)oBarrier to light – turbid, absorbs and scatters lightLand vs AirSenseAirWaterSmellGoodGood, but slowTasteGood, needs contact withliquidsGoodVisionVery GoodVariable – depends onturbidity, light absorptionHearingFairExcellent, 4x faster andfartherTouchMust be in direct contact“Distant” touch – waterincompressibleElectroreceptionNAGood, water conductselectricityMechanoreceptionoWater = dense and incompressible = excellent conductor of vibrationsoMechanosensory systems:Lateral lineInner earSensory Hair CellsoOnly way mechosensing can occuroSensory hair cell will always be firing and sensory neuron will always be receivingRate change depending on whether stereocilia are bending towards or awaykinociliumBending toward kinocilium, fire more rapidly: excitationBend away from kinocilium, fire more slowly: inhibitionVibrations bend the stereocilia Lateral Line SystemoNeuromasts = clusters of sensory hair cellsHead of neuromasts are a cupulaCupula helps make fish less sensitive Vibration has to be strong enough to move the cupula and trigger a response
oWhy is the Lateral Line System Important? *only useful in waterGood for schooling, don’t have to see fish next to themUsed to detect predatorsImportant in the deep, dark crevices, caves, etc.

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