Gaseous exchange in other organisms Flashcards
Describe the respiratory system of an insect
Has spiracles (openings) in the exoskeleton which allows air to enter the system
Tracheae lead to tracheoles
Tracheoles is the main site of gas exchange
Towards the ends of the tracheoles there is tracheal fluid
What is the impact of drawing the tracheal fluid into the muscles on gas exchange?
Allows the muscles to get a supply of oxygen
Decreases the pressure the the tracheoles so allows more oxygen to be drawn in from the spiracle
Increases the surface area available for oxygen to diffuse through
How do flying insects create a rapid flow of oxygen?
Use abdominal muscles to create a pumping movement for ventilation- creating changes of pressure in tracheoles
Describe the respiratory system of the fish
Gills are the organs of gas exchange- continuous flow of water in one direction is maintained
Gills have large surface area, thin layers and good blood supply
Gills are covered by the operculum, filaments and have lamallae which are the main sites of gas exchange
What are the adaptations of the gills to carry out effective gas exchange?
Multiple lamallae on the filaments- large surface area
Lamallae have thin walls- short diffusion distance
Fresh water constantly flows over the gills- good ventilation
Good blood supply- maintain the concentration gradient
Tips of gill filaments overlap- create resistance to the flow of water and slows it down so there is more time for gas exchange to take place
Countercurrent exchange system- blood flow and water flow are in opposite directions so equilibrium is not reached and steep concentration gradients are maintained through the length of the lamallae
What is the ventilation mechanism of fish? Inspiration
Open mouth
Lower floor of buccal cavity
Volume inside buccal cavity increases, pressure decreases so water flows in
Opercular valve shuts, pressure is high again
Water moves from buccal cavity over the gills
What is the ventilation mechanism of fish? Expiration
Closed mouth
Floor of buccal cavity raises, increasing the pressure
Pressure in opercular cavity is greater than outside so water is forced out
