ELECTROGENESIS IN FISHES By ABDUR ROUF SAMIM
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Transcript of ELECTROGENESIS IN FISHES By ABDUR ROUF SAMIM
ELECTROGENESIS IN FISHES
ABDUR ROUF SAMIMM.Sc.(Final) FISHERY SCIENCE AND AQUACULTURE
INTRODUCTIONElectrogenesis refers to the production of
electrical impulses in the tissues of a living organism.
Observed in all animals such as fishes, reptiles, and mammals etc.
TYPES OY ELECTRIC FISHES Strongly electric fishes Example: Torpedo, Electrophorus etc. Weakly electric fishes Example: Raja, Gymnotus etc.
RajaElectrophorus
Electric organs are organs specialized for the production of an electric field outside the body.
Built up from a large number of disc like cells, called electroplates.
Electroplates embedded in a jelly like extracellular material and enclosed within a compartment of connective tissue.
Diagram showing electric organs
ELECTRIC ORGANS
DISTRIBUTION OF ELECTRIC ORGANSName of fishes Shape of electric
organLocation of electric organ
Torpedo Flat kidney shape On either side of mid-line
Malapterurus Lozenge-shape Located in skin
Raja (String ray) Spindle-shape Lying parallel to the spinal cord in the tail
Torpedo Raja
PATTERNS OF ELECTRIC ORGAN DISCHARGESMonophasic pulses Biphasic pulses Polyphasic pulses
KINDS OF ELECTRIC ORGAN DISCHARGE
Electrophorus: one small pulse followed by four large pulse.
Electric shark: repetition of sequence of events.
Torpedo: four large pulses which are continuously repeated.
MECHANISM OF ELECTRIC ORGAN DISCHARGE
+ + + + + + +_ _ _ _ _ _ _
+ + - - - + + + - - + + + - - -
_ _ _ _ _ _ _ + + + + + + +
Resting phase
Action Potential Spike stage
ReceptorSensory Nerve Fibre Brain Optic
Nerve
Electric OrganMotor Nerve
1
2
Pathways of neural control of electric organ
FUNCTION OF ELECTRIC ORGANFood procurement DefenseSpecies and sex recognitionDirection findingCommunicationNavigation
WHY ARE FISHES IMMUNE TO THEIR OWN ELECTRIC CURRENT ?
Got myolated nerve fibers with high degree of insulation.
Excitatory muscle fibers have high threshold of excitation.
Referenceswww.wired.comwww.elguanche.infowww.revolvy.comwww.keywordsuggests.orgBrown, animal physiology ,2nd volume.Notes provided by Prof. Mukhtar Ahmad
Khan.