Inflation/Deflation of physostomous bladder Flashcards
1
Q
How do fish inflate the physostomous bladder?
A
- gulping/swallowing air at water surface
2
Q
How does gulping help inflation?
A
- air diverted through “pneumatic duct” by increasing pressure in buccal cavity
3
Q
Why is gulping less effective in deep water?
A
- high pressure (increases 1 atm evey 10m)
- need large amounts of gas
4
Q
How does a fish deflate the physostomous bladder by reflex?
A
- gas puckreflex/spitting (burp)
5
Q
How does a fish Gas puckreflex? (7)
A
- relax pneumatic sphincter –> contract smooth muscle + recoil of gas bladder wall + contract body wall –> gas released to pneumatic duct –> esophagus –> negative buoyancy (sink)
6
Q
What part of the pneumatic duct reabsorbs gas? why?
A
- ductus pneumaticus
- well vascularized (blood vessels) to pick up reabsorbed gas
