Ventilation in fish and insects Flashcards
what is an operculum
a bony flap which protects gill
what is the buccal cavity
the mouth of a fish
what is the primary lamellae/ gill filaments
The gill filaments, branches of tissue which are attached to the gill
where are gills located on the fish
On the head
Describe the ventilation of a fish
Buccal cavity floor lowers, increasing cavity volume, decreasing cavity pressure.
Water enters due to pressure gradient
Floor raises to push water through gills
Operculum moves outwards to allow water to flow through gills and reduce pressure
when the buccal cavity floor lowers, what happens to the pressure and volume of the cavity
Pressure decreases, volume increases
what is counter current flow
when capillaries which surround the secondary lamellae on gill filaments, blood flow is of opposite direction to the flow of water over the lamellae
allowing capillariws to absorb the maximum amount of oxygen from the water
what supports tracheae in insects
RIngs of chitin which prevent it from collapsing
what is the tracheal system
system of air filled tubes, which exchange gases with the tracheal fluid
How does air enter the tracheal system of insects
through a spiracle in the exoskeleton
in more active insects what can cause ventillation
Body movements
What is different between volumes of air and volumes of wate
Water contains less oxygen than the air
what is the buccal opercular pump
action of buccal cavity and operculum to allow water to keep flowing over the gills secondary lamellae
how does the buccal opercular pump work
when the buccal cavity floow lowers and mouth is open, drawing water into buccal cavity
mouth closes, buccal floor raises, water is pushed from cavity through operculum pushing water over the gills
