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Soft Anatomy. Alimentary canal Gas bladder. Digestive tracts. Spiral valve intestine. Chondricthyes Primitive Bony Fishes Coelacanthiformes Dipnoi Polypteriformes Acipenseriformes. Diet and intestinal length. herbivorous. planktivorous. piscivorous. Gas Bladder.
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Soft Anatomy • Alimentary canal • Gas bladder
Spiral valve intestine • Chondricthyes • Primitive Bony Fishes • Coelacanthiformes • Dipnoi • Polypteriformes • Acipenseriformes
Diet and intestinal length herbivorous planktivorous piscivorous
Gas Bladder • General form: gas filled sac derived from the anterior portion of the alimentary tract • Occurrence of the gas bladder in fishes • Number of gas bladders -monopneumonan -dipneumonan • Kind of gas bladder connections -physostomous -physoclistous
monopneumonan dipneumonan
physostomous pneumatic duct gas bladder physoclistous digestive tract
Gas Bladder Functions • buoyancy control • respiration • sound production • sound reception
Structures associated with gas resorption and gas secretion • Gas gland • gas secretion • Oval • gas resorption • Rete mirabile • Countercurrent gas exchange in blood
physostomous physoclistous
Addition of gas to the bladder • Some physostomes are able to gulp air into the gas bladder
Addition of gas to the bladder • Some physostomes are able to gulp air into the gas bladder • Gas addition in both physostomes and physoclists via gas gland and rete mirabile • Processes involved are: • blood acidification (Bohr and Root effects) • “salting-out” effect • countercurrent exchange (at rete mirabile)
[lactate] + [H+] Gas solubility “Salting out” effect • Reduced gas solubility with increasing concentration of lactate and H+
Metabolic processes for pumping gas into the gas bladder Gas gland Rete mirabile
Resorption of gas from bladder • Physostomes can use Pneumatic duct • Physoclists use highly vascularized Oval area • Oval isolated from main bladder
benthic fishes without a gas bladder Percidae Bothidae Gobiidae
Pelagic sharks with high oil content Charcharhinidae Blue shark Prionace glauca Large livers containing low density lipids & squalene (hydrocarbon d=0.86)
Many deepsea midwater fishes Astronesthidae Astronesthes gemmnifer Reduced density of musculature and skeletal tissues.
Diel Vertical Migrators (DVM) Myctophidae Lanterfish Gonichthys sp. Degenerate bladder or lipid-filled bladder