Fish respiratory system.pdf

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1. Comparative Anatomy of
Respiratory system
with special reference to
Scoliodon, Rana, Varanus, Columbaand Lepus

2. üThedevelopmentoftherespiratoryorgansinvertebratesisclosely
relatedtotheprimitivepharynx,sincethegillsofaquatic
vertebratesandthelungsofterrestrialvertebratesandaquatic
mammalshavepharyngealembryologyorigin

3. üRespirationistheprocessofobtainingoxygenfromtheexternal
environment&eliminatingCO2.
üAcquisitionofmolecularoxygen(O2)fromtheexternalmedia
(waterandair)andthedischargeofcarbondioxide(CO2)into
thesamemilieuistheprimaryroleofrespiration
üExternalrespiration-oxygenandcarbondioxideexchanged
betweentheexternalenvironment&thebodycells
üInternalrespiration-cellsuseoxygenforATPproduction(&
producecarbondioxideintheprocess)
Water/ Air
O2
CO2CO2
O2
Respiratory organ

4. üVertebrateshavedevelopedavarietyofrespiratorysurfaces
thatallincreasethesurfaceareaforexchange,thusallowingfor
largerbodies.
üArespiratorysurfaceiscoveredwiththin,moistepithelialcells
thatallowoxygenandcarbondioxidetoexchange.
üThosegasescanonlycrosscellmembraneswhentheyaredissolvedin
wateroranaqueoussolution,thusrespiratorysurfacesmustbe
moist.
Characteristic of respiratory organ

5. The system that has evolved in each species depends on the
environmental conditions, on body build and size, on animal’s
patterns of movement and on its energy consumption

6. RespirationinFish

7. Organ present for respiration in fish
1) Gills2) Air/ swim bladder
Only present in crossoptergii
and lung fishes (Assessory
respiratory organ)
A)Internal gills
All fish
B) External Gills
Larvae of lung fish
Polypterus
Lepidosiren

8. üGillsarerespiratoryorganfoundinmanyaquaticorganisms
thatextractsdissolvedoxygenfromwaterandexcretes
carbondioxide.
üOnthebasisoflocationgillsareoftwotypes:
1)Internalgills
2)Externalgills
Gills

9. üCharacteristicoffishes
üLocatedinthegillsslitsandattachedtovisceralarches
1)Internalgillsortruegills
üGillsusuallyconsistofthinfilamentsoftissue,branches,or
slender,tuftedprocessesthathaveahighlyfoldedsurfaceto
increasesurfacearea.
üAhighsurfaceareaiscrucialtothegasexchangeofaquatic
organisms,aswatercontainsonlyasmallfractionofthedissolved
oxygenthatairdoes.
Structure

10. üThegillsaremultifunctionalorgansthatareresponsibleforthegas
exchange(respiration)butalsofortheosmoregulation,acid-base
regulation,andexcretionofnitrogenouswaste

11. Structure of true gills

14. üGills–finallydividedgillfilamentandlamellae
üProvideverylargesurfaceareaforgasexchange

17. üEachtruegillissupportedbyagillarch/gillcleft–abony
structurethatisorientedverticallyonthesideofafish,justbehindits
head.
üThegillarchprovidesthesupporttoholdanumberofcomb-
likestructurescalledgillfilaments.
üGillfilamentsextendouthorizontallyfromthegillarches.
üEachgillfilamentalsocalledprimarylamellaeandtheprimary
lamellaebranchoutintotinysecondarylamellae.
üThesecondarylamellae,whichareextremelynumerous,arethesite
ofgaseousexchangeandformafinesievewhichensuresthatall
thewatercomesintoclosecontactwiththeblood
üThesecondarylamellaerunparalleltotheflowofthewaterand
absorboxygenfromthewaterintothefish’sbody.

18. Gills in elasmobranch and bony fishes
Gillsofelasmobranch(eg.Dogfish)aregeneralinstructure.
Gillsofbonyfishesarealsobasicallysimilarbutshowthefollowing
differences
1)Operculum:bonyflaporgillcoverarisesfromthehyoidarchcovers
thegills,whichopensbyaSingleslitlikecresecentexternalgill
opening
2)Interbranchialseptm:Themedianseptumisdevelopedin
elasmobranchandreducedinteleost
3)Spiracles:Inelasmobranchandganoidsthefirstgillslit,between
mandibularandhyoidarches,bearsareducedpseudobranchand
openstooutsidethroughsmallopening,spiracle.Inchimarasand
lungfish,teleost,spiraclebecomeeitherclosedorlost.
4)Number:5-7pairsincartilaginousand4pairsinbonyfishes

20. üAsinglerowoflamellaeononesideofbranchialseptumformsonly
halfthegill,calledademibranchorhemibranch.
üAseptumwithtwoattachedelsmobranchscompriseacompletegill
areholobranch.

21. Anatomy of respiratory system
in Scoliodon

22. üRespirationisaquatic
üBreathebygillsborneinaseriesofgill-pouchesoneitherlateralsideofthe
pharynx
üWaterentersthemouthandafterpassingthroughthebuccalcavity,
pharynx,gill-pouchesbearinggill-lamallae,goesoutthroughtheexternal
gill-slitsafterbathingthegills
üFivepairsofgill-pouchesbearinggills,arrangedinaseriesbehindthehyoid
archinthelateralwallsofthepharynx.
üInDogfish(Scoliodon),thehyoidarchbearsonlyahemibranchonits
posteriorsurface,thefirstfourbranchialarcheshasholobranchsandthe
fifthbranchialarchiswithoutanygill(abranch).
üThus,ithasninehemibranchs

24. üEachgill-pouchhastwosetsofgill-lamellae,oneonitsanteriorwalland
theotherontheposterior.Eachsetoflamellaeisahalfgillorhemibranch,so
thatgill-pouchhastwohemibranches
üCommunicateswiththecavityofthepharynxthroughalargeinternalbranchial
apertureandwiththeexteriorthroughanarrowexternalbranchialaperture
(commonlycalledgill-slit)
üInterbranchialseptaisraisedintoaseriesofhorizontalfoldstoform
lamelliformsbranchiallamellaeorgill-filaments
üRichbloodsupply,andtheyhaveaverythincoveringmembranethrough
whichbloodisexposedtoseawaterforanexchangeofgases.

26. b) External Gills
üExternalgillsareformedasbranchingoutgrowthsfromthe
exposedouterepitheliumofgill
üArchesnotfromthepharyngealpouches.
üTheyaretemporaryorgansfoundonlyinthelarvalstages
üTheyoccurinthelarvaoflampreys,afewbonyfishesincluding
Polypterus,lungfishes(Lepidosiren)

27. 2) Swim bladder/ Air bladder
Origin of lungs in higher vertebrates
üMostvertebratesdevelopanoutpocketingofpharynxor
oesophagusthatbecomesoneorapairofsacs(swimbladdersor
lungs)filledwithgasesderiveddirectlyorindirectlyfromthe
atmosphere.
üSimilaritiesbetweenswimbladders&lungsindicatetheyarethe
sameorgans.
üVertebrateswithoutswimbladdersorlungsincludecyclostomes,
cartilaginousfish,andafewteleosts(e.g.,floundersandotherbottom-
dwellers).

28. Duringtheontogenesisofhighervertebrates,thepharyngeal
pouchesfailtoopentotheoutside
üInhighervertebrates,thepharyngealpouchesjustremainduringthe
embryonicperiod,wheretheyundergoseveralchanges,butvery
fewornoneoftheirinitialcharacteristicsarepresentedinadults.
üInamniotes,asinhumans,onlythefirstpairofpharyngealpouches
remains,givingoriginbilaterally,theeustachiantubeandmiddle
ear

29. Respiratory system
in Tetrapods

30. üMostadultamphibiansandallamniotesbreathebymeansoflungs
üInanembryoahollowoutpushingofsinglemidventraldiverticulum(lung
primordial)theventralwallofthepharynx.
üItgrowsbackwardsanddividesintotwo,rightandleftlungbuds.The
undividedproximalportiondevelopsintotracheaandlarynx,andopensinto
pharynxbyglottis.

31. üInlowerforms,thelungsarehollowbags,butinhigherformstheridges
increaseinnumberandunitewithoneanotheracrossthelumenofthe
lungtoconvertitintoasolidbutspongystructurewithinnumerableair
spaces
üInmammals,theinternalsurfaceareaoflungsmaybethirtytimesthatof
theexternalsurfaceareaofthebody
Lungs and Duct
Larynx
Trachea
Lungs Proper

32. 1) LarynxAmphibia
üBeginningsoflarynxareseeninAmphibia
üSimplestcondition(Nectrus),itissupportedbyapairof
lateralcartilages,boundingtheslit-likeglottis
üInAnura,innerliningoflaryngotrachealchamber
formstwomuscularbands,orvocalcords,whichvibrateto
producevariouscalls
Birds
üItissmallandrudimentaryinbirdsand
anotherorganispresent,thesyrinx
üSyrinx:locatedatthelowerendoftrachea
responsibleforsoundproduction.
üSyrinxtympanumformedoflasttrachealcartilage.
Reptiles
üLarynxisscarcelydevelopedinreptiles

33. Mammals
üLarynxreachesitsgreatestpointof
evolutioninmammals
üBesidespairedarytenoidandsinglethyroid
cartilageisaddedonventralsurfaceoflarynx
üVocalcordsreachmaximum
differentiationinmammals
üAflapofmuscularepiglottisispresentin
frontofglottisandischaracteristicof
mammals
üInsingingbirds,pairedofvibratorymembranecalled
membranesemilunariswhichextenddorsoventrallynearthe
junctionofbronchiandtrachea.

34. 2) Trachea
Amphibia
üTracheaisextremelyshortorabsentinAnura
üItismergedwiththelarynxtoformlaryngotrachealchamber
Reptiles
üSimpleinreptilesasinamphibiansormaybelonginlong-necked
reptilessuchasturtles,tracheaislongandconvoluted
üTrachealcartilagesaresometimesintheformofcompleterings
Birds
üInbirds,thetracheaislong.Inswansandcranes,tracheaislonger
thantheneckandtrachealringsarecompleteandossified.
Mammals
üTracheainmammalsisvariableandtrachealringsareusually
incompleteontheupperside

35. 3) Lungs
Amphibians
üInamphibiansthelungsaresimple,sac-likestructureswitha
centrallargecavity.
üInaquaticamphibianstheinnersurfaceoflungsissmooth.
üInfrogsandtoadstheinnerwallscontainnumerousfolds
linedwithalveolisoastoincreasetherespiratorysurface.
üTheyarerichlyvascularandlinedwithmucousepithelium
whosecellsarecolumnarandciliated.

36. Structure of
respiratory system in
Rana (Frog)

37. Structure of respiratory system in Rana (Frog)

38. Respiratory tractconsists of:
üExternal nostril
üNasal chambers
üInternal nostrils
üBucco-pharyngeal cavity
üGlottis: On the floor of pharynx, the median slit-like glottis is present Glottis
opens into larynx.
üLaryngo-tracheal chamber: Larynx or laryngo-tracheal chamber is a thin
walled. Cartilages (2 arytenoid + 1 cricoid) support the walls of larynx
Its internal lining forms a pair of elastic horizontal bands, the vocal cords.
The characteristic croaking is produced because of the vibrations formed when
the air from lungs is forced outside.
Only male frogs have vocal sacs so as to amplify the croaking sound.
üFrom larynx, bronchus leads to each lung
üTwo bronchi

41. LungsinRana:
üLungsareovoidinstructure.
üTheyarethin-walledandhighlyelasticsacs
üTheyaresuspendedfreelyinsidetheperitonealbodycavity,oneon
eithersideoftheheart
üPeritoneumcoversthelungexternally.
üTheinnersurfaceofeachlungisdividedbysepta(anetworkoffolds)
intomanysmallairsacsoralveoli,leavingaclearlargecentralcavity.
üThealveoliarelinedbythinepithelium
üThisepitheliumisrichlysuppliedwithbloodcapillariesthatcontainsde-
oxygenatedbloodforgaseousexchange.
üO2intheinhaledairdiffusedtobloodwhereasCO2isreleasedintoalveoli.

43. Lungs in Amphibian: Simple, sac-like structure