Gas exchange in aquatic animals Flashcards
How do sessile molluscs meet their oxygen needs?
Gills, unidirectional counter current, water moved with cilia
How do clams meet their oxygen needs?
Flat sheet-like gills with filaments to increase surface area. Unidirectional counter current
How do cephalopods meet their oxygen needs?
Muscle contractions of the mantle cavity will move water across their gills. Unidirectional countercurrent
How do land snails meet their oxygen needs?
Highly vascularized mantle cavity. Unidirectional countercurrent
How do crustaceans meet their oxygen needs?
Use gill bailers to drive water across the gills and out the mouth. Unidirectional counter current
How do sea stars meet their oxygen needs?
Uses respiratory papulae and tube feet. Move water from the mouth and through the papulae. Unidirectional counter current
How do sea cucumbers meet their respiratory needs?
Respiratory tree. Water passes through the digestive tract and the respiratory tree takes the oxygen as it passes by. Unidirectional countercurrent
What ventilation system do jawless fish use?
Tidal (unidirectional tidal)
How do hagfish meet their respiratory needs?
The velum pumps water from the mouth, through the gill sacs, and out the gill opening. Unidirectional counter current
How do lamprey meet their respiratory needs when they aren’t feeding?
Similar to the hagfish, where velum pumps water from the mouth, across the gills, and through the gill opening out.
How do lamprey meet their respiratory needs when they are feeding?
Unidirectional tidal ventilation through the outer openings. They get a lot from the host
What ventilation system do elasmobranchs use?
Buccal pump
How does the buccal pump work?
The fish sucks in water through the mouth and spiracles, closes the mouth and pressure increases in the buccal cavity, then the cavity contracts and forces the water through thegill slits
What ventilation system do teleost fish use?
Buccal opercular pump
What is the gill structure in teleost fish?
Gills are arranged into gill arches. The arches are V shaped and have 2 layers of gill filaments, and the gill filaments have two rows of lamellae
What did Hughes and Shelton do?
Did a bunch of pressure measurements in a trout to determine how the buccal opercular pump works
What were the 4 things Hughes and Shelton measured?
- Opening and closing of the mouth and buccal valve
- Opening and closing of the operculum
- Pressure in the buccal cavity
- Pressure in the opercular cavity
What happens in phase 1 of the buccal opercular pump?
The mouth opens, buccal cavity expands, buccal valve opens, operculum expands, opercular valve closed. Negative pressure in the opercular cavity and positive pressure in the buccal cavity
What happens in phase 2 of the buccal opercular pump?
Mouth closes, buccal valve closes, buccal cavity expands, opercular cavity expands, opercular valves closed. Positive pressure in buccal cavity and negative pressure in the opercular cavity
What happens in phase 3 of the buccal opercular pump?
Mouth closed, buccal valve closed, buccal cavity contracts, opercular cavity contracts, opercular valves open. Positive pressure in the buccal cavity.
What happens in phase 4 of the buccal opercular pump?
Mouth opens, buccal valve opens, operculum contracts completely, opercular valves close. Negative pressure in the buccal cavity
What were the 3 things that Hughes and Shelton concluded from their experiment?
- Positive pressure in the buccal cavity in phases 1, 2, 3
- Negative pressure in the opercular cavity in phases 1,2
- Highly coordinated and takes about 0.5 seconds to complete a full cycle
What fish use ram ventilation?
Some teleost fish like tuna and mackerel that swim rapidly for long periods of time
Why do tuna use ram ventilation?
They are so active that the buccal opercular pump isn’t enough
How does ram ventilation work?
The fish swim with their mouth open and constantly force water through the gills
