Fish Natural History: Buoyancy Regulation

Front 1

list the 3 functions of the gas bladder

Back 1

1. buoyancy regulation
   
2. respiration
3. sound reception

Front 2

[ buoyancy regulation ]

what is buoyancy regulation?

Back 2

maintaining a position in the water column

Front 3

[ buoyancy regulation ]

gas bladder

Back 3

• flexible gas-filled chamber in body cavity
  
• most Teleosts have these while most benthic species do not

Front 4

the gas bladder forms as...

Back 4

out pocket of the esophagus during embryonic development

Front 5

pneumatic duct

Back 5

connection between gas bladder and gut

Front 6

[ buoyancy regulation ]

physostomous gas bladder

Back 6

retain the pneumatic duct

Front 7

[ buoyancy regulation ]

physoclistous gas bladder

Back 7

pneumatic duct is not retained (MOST fishes)

Front 8

[ buoyancy regulation ]

neutrally buoyant

Back 8

maintain position in water column without expending energy

Front 9

[ buoyancy regulation ]

oval body

Back 9

highly vascularized circular portion at the top of the swim bladder

Front 10

as a fish ascends, the volume of the gas bladder ___________ due to _____________, and the fish must ____________ to maintain neutral buoyancy

Back 10

as a fish ascends, the volume of the gas bladder increases due to decreasing pressure, and the fish must release gas to maintain neutral buoyancy

Front 11

[ buoyancy regulation ]

gas release in physostomes

Back 11

release gas through the esophagus and out of the mouth

Front 12

[ buoyancy regulation ]

gas release in physoclists

Back 12

release gas through the bloodstream

Front 13

as a fish descends, the volume of the gas bladder ___________ due to _____________, and the fish must ____________ to maintain neutral buoyancy

Back 13

as a fish descends, the volume of the gas bladder decreases due to increasing pressure and the fish must add gas to maintain neutral buoyancy

Front 14

[ buoyancy regulation ]

gas addition

Back 14

• moving gases from blood back into swim bladder
• uses gas gland on the bottom of the gas bladder
  

Front 15

gas gland

Back 15

special vascularized region of the bladder which is the site of gas addition by the diffusion of gases from the blood into the gas bladder

Front 16

[ buoyancy regulation ]

rete mirable (gas addition)

Back 16

• "wonderful net"
• bundle of capillaries where the arterial capillaries and venous capillaries lie adjacent but in opposite directions
• countercurrent flow: the countercurrent arrangement of the rete capillaries helps build up the levels of diffusible gases in the gas gland