Lec 15 Respiration Flashcards
How do fishes obtain oxygen?
Through a continuous flow of water over the gills.
What do gills do in particular to obtain air?
They remove oxygen that’s dissolved in water
What does the unidirectional oxygen flow of water do?
The unidirectional flow pattern eliminates the waste associated with dead air space and make it possible to maintain a constant gradient for oxygen to diffuse from the water into the blood by way of gills
Where is does the water enter and exit?
enter through the water and exit by the opercular opening on the side of the head.
What is the cycle of respiration that can be divided in phases?
- opercular suction pump
- pressure is reduced
- buccal pressure pump
- pressure is reversed
What happens in Opercular suction pump
Water is sucked into the mouth due to the high negative pressure.
What happens during the reduced pressure?
Mouth closes and buccal cavity contracts, creating positive pressure in the buccal cavity
What occurs during the buccal pressure pump?
Pressure is positive in both cavities. Water is pushed out of the opercular opening.
What occurs during the buccal cavity?
It expands while opercular cavity is still being compressed.
How does time duration vary among fishes?
Depends on speed and oxygen availability in the environment.
What pump dominates in slowly swimming fishes?
the opercular pump predominates
What pump dominates in faster swimming fishes?
the buccal pump predominates
What happens in pelagic forms with the buccal and opercular cavities?
pumps may not be used as all. Water flow in and through the buccal and opercular cavities is enough to supply adequate oxygen to the gills.
Stream of water can be regulated simply the degree of mouth opening
What phase is increased in bottom living fishes?
Increase of opercular pump phase.
What is the gill structure like?
Sieve like structure that’s in path of respiratory flow
each gill arch has gill filaments or holobranches which is made up of two halves called hemibranches
