L11-12_SensoryHO11 - 1 EEMB 106 Lectures 11-12 Sensory...

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EEMB 106 – Lectures 11-12 – Sensory systems Density of fish flesh is close to the density of water Properties of water 1) Dense: 800x more dense than air 2) Incompressible: any particle that moves, moves a particle next to it. More energy required to produce sound, but it propagates further and faster than in air A) Motion sensors: lateral line - senses water movement; unique to fish B) Sound sensors: otoliths and swimbladder; fish do not need external ears: why? All fish need is an internal organ that either is more dense or less dense than water. 3) Conducts electricity well (salt water especially well) A) Ampullae of Lorenzini: ampullary receptors in sharks; do not produce electricity. B) Ampullary receptors and tuberous receptors: in Osteichthyes 4) Barrier to light: turbid, absorbing and scattering light rays. A) Light is selectively filtered out with depth. E.g. red, orange >>> green, blue 5) Chemicals in solution: chemoreception (taste and smell) can occur all over the body Sensors : convert physical or chemical stimuli from the environment into signals that are transmitted to other parts of the nervous system, primarily the brain, for processing and interpretation. Sense Air Water Smell good good, but slow Taste good, need contact with liquids good Vision very good good to not possible: depends on light absorption Hearing fair excellent, 4X faster and farther Distant touch Not possible good: incompressibility of water Electroreception Not possible good: water conducts electricity Fish brain – the central processor 1) forebrain (telencephalon + olfactory bulbs) = olfaction 2) “between-brain” (diencephalon+ pineal gland) = homeostasis, endocrine, circadian rhythm 3) midbrain (mesencephalon + optic lobes) = vision 4) hindbrain (cerebellum) = hearing, balance and lateral line (acoustico-lateralis system) 5) brainstem (Medulla oblongata + facial and vagal lobes) = lateral line, electroreception, taste Chemoreception 1. Olfaction (smell) •olfactory receptors in pits •can be extremely sensitive 2. Gustation (taste) •similar to humans, except… •more acute (one molecule per receptor) •sensory cells (“taste buds”) not confined to mouth - barbels, Fins, flanks A. Olfaction Receptors in olfactory pits: in- and ex-current channels Receptors arranged on a rosette of lamellae (folds) Water contains molecular cues
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This note was uploaded on 01/10/2012 for the course EEMB 106 taught by Professor Staff during the Spring '08 term at UCSB.

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L11-12_SensoryHO11 - 1 EEMB 106 Lectures 11-12 Sensory...

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