Welcome to JAAN's science class!!

Big hi to all of you! I'm an undergraduate following a Bsc in bioscience. Trust me I know the feeling of surfing around the net for ages and getting nothing in return! Or getting something worthless for the time we spent surfing. So I started this blog adding the science stuff I have noted which I think might help someone in their home work. Ok then enjoy!

31 May 2011

Internal gill structures of aquatic vertebrates

INTERNAL GILLS

·         Pouched gills: in agnathans – lamp rays
·         Septal gills: in chondrichthyes
·          Aseptal gills: in osteichthyes

Pouched gills
·         Large sac like branchial pouches which are lined with primary gill lamellae.
·         Water goes through mouth àpharynx àpore shaped internal gill slitsàbranchial pouches.
·         Water leaves the branchial pouches through pore shaped external gill slits.

Septal gills
·         Branchial pouches are narrow chambers.
·         Between the branchial chambers, para branchial chambers are present with external gill slits. External gill slits are small and slit shaped.
·         Distal tips of the interbranchial septa can act as valves to close the external gill slits.
·         Gill lamellae runs along the interbranchial septa towards the body surface.
·         Internal gill slits rise from the pharynx and run into each branchial chamber.

Aseptal (non-septal) gills
·         Operculum covers the gills.
·         A single large opercula cavity is present with one valved external gill slit.
·         Interbranchial septa are greatly reduced.
·         Therefore gill lamellae extend freely into the opercula cavity.





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