mechanism of ventilation in fish and insects Flashcards

1
Q

name and describe the two main features of a fish’s transport system

A

gills: located within the body, supported by arches, along which are multiple projections of gill filaments, which are stacked up in piles
lamellae: at right angles to the gill filaments, give an increased surface, blood and water flow across them in opposite directions (counter-current exchange system)

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2
Q

explain the process of gas exchange in fish

A
  • buccal cavity volume increased to enable water to flow in, reduced to increase pressure
  • water is pumped over the lamellae by the operculum, oxygen diffuses into the bloodstream
  • waste carbon dioxide diffuses into the water and flows back out of the gills
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3
Q

how does the countercurrent exchange system maximise oxygen absorbed by the fish?

A
  • maintains a steep concentration gradient, as water is always next to blood of a lower oxygen concentration
  • keeps rate of diffusion constant and enables 80% of available oxygen to be absorbed
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4
Q

name and describe the 3 main features of an insect’s gas transport system

A

spiracles: holes on the body’s surface which may be opened or closed by a valve for gas or water exchange
tracheae: large tubes extending through all body tissues, supported by rings to prevent collapse
tracheoles: smaller branches dividing off the tracheae

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5
Q

explain the process of gas exchange in insects

A
  • gases move in and out of the tracheae through spiracles
  • a diffusion gradient allows oxygen to diffuse into the body tissue while waste CO2 diffuses out
  • contraction of muscles in the tracheae allows mass movement of air in and out
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