To understand the accesary respiratory organs in fishes

1. ACCESSORY RESPIRATORY ORGANS IN FISH
Dr.T.SAKTHIKA ,
ASSISTANT PROFESSOR OF ZOOLOGY
A.PC.MAHALAXMI COLLEGE FOR WOMEN,
THOOTHUKUDI

2. ACCESSORY RESPIRATORY ORGANS IN FISHES –are extra respiratory organs Or Air breathing
organs
Reasons for existence- Environmental O2 deficiency- degenerate gills- aestivation- counter
balance internal O2 deficiency- obligatory in some fishes
Types
Integument-Eel(Anguilla)- skin-vascularized- aerial respiration –in land
Pelvic fins- Lepidosiren (lung fish)- pelvic fin- male- filamentous outgrowth –breeding season-
vascularized-gas exchange – guarding eggs
Oral papilla- Electric Eel(Electrophorus)-mucous membrane of mouth raised – oralpapillae-
vascularized
Buccopharynx- Mudskipper(Periophthalmus)-inner lining of buccal cavity and pharynx-
vascularized- aerial respiration
Intestine-Loaches(Lepidocephalichths)-intestine well vascularized- gulp air- respires with the
help of intestine- expiratory air- anus
Pharyngeal lungs (Ophiocephalus)- air chambers – outgrowth of pharynx- air drawn in –
through mouth- expired air out –gills.
,

3. Opercular lungs (Anabas, clarius)- air chamber-outgrowth of branchial chamber- 3forms
labyrinthine organs- Anabas- 2 opercular luns- ourgrowth of branchial chamber-
concentrically arranges wavy plates- labyrinthine organs-covered by vascular membrane- out
of water-6-7yrs
Arborescent organs or tubular sacs or dentriform organs- Anabas- tree like branched vascular
organs- outgrowth of 2nd and 4th gill arches- used for aerial respiration
Tubular sacs- out growth of branchial chambers-Sacchobranchus- extend up to tail-
communicate with buccal cavity by 2 openings- air goes in and out through these openings
Lungs- Protopterus, Lepidosiren- pair of lungs- open in to oesophagus by glottis- alveoli in the
lungs are vascularized
Airbladder- gas filled sac- above alimentary canal- open in to pharynx –pneumatic duct

4. Eel, Lepidisiren, Electric eel, Periophtalmus, Anabas