RespirationRespiration

Jawless FishesJawless Fishes

Gills - pore-like openings 7 pairs of gill pouches in lamprey 5-15 pairs of gill pouches in hagfish, but

varying numbers of openings (as few as one/side)

Gills - pore-like openings 7 pairs of gill pouches in lamprey 5-15 pairs of gill pouches in hagfish, but

varying numbers of openings (as few as one/side)

Hagfish gillsHagfish gills

Gill pouches connect directly to pharynx Two gills in each pouch May or may not open directly to outside

(depending on species) May play role in digestion/nutrient absorption

Gill pouches connect directly to pharynx Two gills in each pouch May or may not open directly to outside

(depending on species) May play role in digestion/nutrient absorption

LampreysLampreys

Problems with respiration during feeding - no water via pharynx

Developed separate canal to carry respiratory water - from pore on head to gill pouches

Problems with respiration during feeding - no water via pharynx

Developed separate canal to carry respiratory water - from pore on head to gill pouches

Lamprey gillsLamprey gills

Two gills per pouch Each pouch has separate exit pore to

outside

Two gills per pouch Each pouch has separate exit pore to

outside

Gills in Chondricthyes and Osteichthyes

Gills in Chondricthyes and Osteichthyes

Gill filaments attached to posterior sides of bony or cartilaginous gill arches

Gill rakers located on anterior sides of arches

Gill filaments attached to posterior sides of bony or cartilaginous gill arches

Gill rakers located on anterior sides of arches

Class ChondrichthyesClass Chondrichthyes

Gills (pairs of them) located in separate chambers leading from pharynx

Chambers separated by septa (tissues) gills are septate

Each has separate gill slit to outside

Gills (pairs of them) located in separate chambers leading from pharynx

Chambers separated by septa (tissues) gills are septate

Each has separate gill slit to outside

Skates and raysSkates and rays

Skates and rays have ventral gill slits Skates and rays have ventral gill slits

Skates and raysSkates and rays

Spiracle behind each eye - better developed in skates and rays than in sharks

Likely a modified gill slit Used to take in respiratory water in benthic

skates and rays

Spiracle behind each eye - better developed in skates and rays than in sharks

Likely a modified gill slit Used to take in respiratory water in benthic

skates and rays

Osteichthyes gillsOsteichthyes gills

Respiration via 4 pairs of gills

No individual openings to outside

Gills on each side covered by single, flap-like operculum

Respiration via 4 pairs of gills

No individual openings to outside

Gills on each side covered by single, flap-like operculum

Branchiostegal raysBranchiostegal rays

Associated with operculum

Allow for expanding volume of mouth, pharynx chambers while keeping opercula closed

Accordian-like action

Associated with operculum

Allow for expanding volume of mouth, pharynx chambers while keeping opercula closed

Accordian-like action

Osteichthyes gillsOsteichthyes gills

Each gill is actually a pair of rows of filaments each attached to the same gill arch

Gills not separated by septa - aseptate

Each gill is actually a pair of rows of filaments each attached to the same gill arch

Gills not separated by septa - aseptate

Aseptate gillsAseptate gills

Gill StructureGill Structure

Gill fine structureGill fine structure

Filaments are not simple finger-like tissues Each filament comprised of stacked plates or

lamellae Greatly increases surface area for interaction with

water flowing across gills (water flows between lamellae)

Filaments are not simple finger-like tissues Each filament comprised of stacked plates or

lamellae Greatly increases surface area for interaction with

water flowing across gills (water flows between lamellae)

Dual Respiratory SystemsDual Respiratory Systems

Some fish have dual respiratory systems

Gills and lungs

Some fish have dual respiratory systems

Gills and lungs

Gills and lungsGills and lungs

Gills are main respiratory organs Lungs serve as back-up system when

gills no longer capable of providing gas exchange

Gills are main respiratory organs Lungs serve as back-up system when

gills no longer capable of providing gas exchange

LungsLungs

LungsLungs

Pouches branch off esophagus Breathe air at surface or when they

remain out of water

Pouches branch off esophagus Breathe air at surface or when they

remain out of water

Paired lungs in lungfishPaired lungs in lungfish

Lungfish lung - leftLungfish lung - left

Lungfish lungLungfish lung

Lungs are mostly simple sacs with network of arteries, veins

Only the most intricate have beginnings of internal compartmentalization

Lungs are mostly simple sacs with network of arteries, veins

Only the most intricate have beginnings of internal compartmentalization

LungsLungs

Paired lungs necessary because of alternating wet and dry periods

Become main respiratory organ when gills become useless

Paired lungs necessary because of alternating wet and dry periods

Become main respiratory organ when gills become useless

Lungs in many fishLungs in many fish

Lungs are present in many of the more primitive fishes

Lungfish, bichir, gars, bowfin relatives, sturgeons

All have varying connections with esophagus

Lungs are present in many of the more primitive fishes

Lungfish, bichir, gars, bowfin relatives, sturgeons

All have varying connections with esophagus

Swim BladderSwim Bladder

Swim bladder probably arose from paired lungs of primitive fish

Lungs were present before swim bladder

Swim bladder probably arose from paired lungs of primitive fish

Lungs were present before swim bladder

Other respiratory organsOther respiratory organs

Mudskippers and European eels can derive significant amounts (10-90%) of oxygen via cutaneous respiration

Mudskippers and European eels can derive significant amounts (10-90%) of oxygen via cutaneous respiration

Other respiratory organsOther respiratory organs

Walking catfishes (Clariidae) use suprabranchial arborescent organs to respire during their “walks”

Bush-like extensions from gills that do not collapse when out of water

Walking catfishes (Clariidae) use suprabranchial arborescent organs to respire during their “walks”

Bush-like extensions from gills that do not collapse when out of water

Other respiratory organsOther respiratory organs

Mudskippers have folded and highly vascularized interior walls of opercula/gill chambers, diverticula in mouth and pharyngeal cavities (snakeheads also have the latter)

Mudskippers have folded and highly vascularized interior walls of opercula/gill chambers, diverticula in mouth and pharyngeal cavities (snakeheads also have the latter)

Other respiratory organsOther respiratory organs

Armored catfishes (Loricariidae) use thin-walled stomach for respiration

Loaches (Cobitidae) use middle/posterior portions of digestive tract

Armored catfishes (Loricariidae) use thin-walled stomach for respiration

Loaches (Cobitidae) use middle/posterior portions of digestive tract