GAS EXCHANGE IN FISH Flashcards Preview

3 ADAPTIONS FOR GAS EXCHANGE > GAS EXCHANGE IN FISH > Flashcards

Flashcards in GAS EXCHANGE IN FISH Deck (15):
1

Gills properties (3)

- one-way current
- many folds increase SA
- flowing water prevents gills collapsing

2

Cartilaginous fish - example and gills (4)

- Sharks
- five spaces on each side = gill pouches
- open at gill slits
- cartilage skeleton

3

Ventilation in cartilaginous fish (3)

- no special mechanism
- must keep swimming to force water over gills
- blood and water travel in the same direction

4

Parallel flow (2)

- diffusion only occurs until equilibrium (50%)
- only occurs on part of the lamellae

5

Bony fish properties (3)

- bone skeleton
- gills covered by flap = operculum
- fresh & seawater

6

Ventilation in bony fish (2)

- continuous unidirectional flow
- water forced over gill filaments by pressure difference

7

Bony ventilation mechanism mnemonic (2)

- Most Observant Flamingos Value Pretty Wafers
Mouth Operculum Floor Volume Pressure Water

8

Bony ventilation mechanism (in) (6)

- Mouth opens
- Operculum closes
- Floor of mouth lowers
- Volume (in mouth) increases
- Pressure (in mouth) decreases
- Water flows in because pressure is higher outside than inside

9

Bony ventilation mechanism (out) (6)

- Mouth closes
- Operculum opens
- Floor of mouth is raised
- Volume in mouth decreases
- Pressure in mouth decreases
- Water flows out because pressure internally is higher than externally

10

Bony fish gills (2 + 3 & explanation)

- Each gill supported by gill arch/bar
- Small projections across arch = gill filaments
- Gill lamellae (resp surface) held apart by water flow increasing S/A

11

Why do fish die outside water? (5)

- Need water to hold gill lamellae apart
- if not they collapse
- less surface area
- therefore less respiration
- therefore death

12

Counter-current flow (3)

- Across entire lamellae
- blood & water flow in opposite directions
- more efficient than parallel (80%)

13

Why is efficient gas exchange important in fish? (1)

- much less o2 in water than air

14

Bony fish CO2 exchange (2)

- occur along entire lamellae
- more efficient than cartilaginous fish

15

Gills in bony fish are... (3)

- specialised respiratory surface
- large surface extended by gill filaments & lamellae
- extensive network of capilliaries