Mechanisms of Gill Ventilation Flashcards
Gill ventilation involves a ___. What is it called?
- dual pump
- buccal-opercular pump
How does dual pump work?
- buccal (pressure) PUSHES water across gills while opercular (pressure) PULLS water across gill
What does the buccal-opercular pump do?
- synchronously delivers near uniform water flow
The buccal-opercular pump is ____.
- unidirectional
What happens to the buccal and opercular cavities when the mouth opens?
- floor of mouth drops, putting more water in buccal cavity (pressure pulls water through gill sieve to opercular cavity)
How do fish increase ventilation? What does this do?
- increase volume, depth of breath and frequency
- supplies water to gill for gas exchange
What happens after the floor of the mouth raises?
- buccal cavity pushes water to opercular cavity and out of gill
What is different about larval lamprey ventilation?
- no buccal or opercular pump = velar pump
The velum is ___
muscular
How does water move in the velar pump?
- UNIDIRECTIONAL
- in through mouth, through gills and out of pores
How does the velar pump and compression-recoil of branchial chamber work?
- velum pulls down dragging water in
- compression causes positive pressure which forces water out
- recoil causes negative pressure which pulls more water in through the mouth
What fish use tidal ventilation?
- parasitic feeders
- mouth is suction cup - cant breathe thru mouth while attached
Why cant parasitic feeders use their nostrils while feeding?
- they are dead end
How do tidal breathers breathe?
- in/out branchiophores
How do post metamorphic lamprey breathe?
via compression recoil
Describe how post metamorphic lamprey breathe
- contraction of branchial musculature forces water out across gills and external branchiophore
- elastic recoil that expands branchial pouch to draw in water
What kind of feeders are hagfish
- scavengers
Explain hagfish ventilation
- unidirectional using vellar pump
- in through nostril, out through branchiophore
What is apnea?
- not breathing/holding breath while they burrow into prey
Hagfish have one nostril that ___ ___ ____
- continues through body
What kind of pump do elasmobranchs use?
- buccal-parabranchial pump
- gill slits
Why do elasmobranchs use a buccal-parabranchial pump?
- they lack operculum = use gill slits instead
What is the architecture of buccal-parabranchial pump?
- lamella extending from filament
What do gill arches consist of?
- 4 holobranch
- 1 hemibranch
