AS

A2

Gas exchange in Animals










Using a spirometer 



Click here to see a basic animation of how a spirometer works. 
Respiration in Fish.

A very simple video showing how fish get oxygen from water.



Here is a great introductory video showing how fish use gills to get oxygen.



Click here to see a simple animation of how a counter current increases the efficiency of diffusion.



A brilliant video (kind of) describing how oxygen pressure contributes to different gas exchange systems (watch it for a laugh at least!)


Gas exchange in Insects
Gas exchange in Insects.

Tubes called trachea penetrate inside the body carrying air to every tissue.
Tracheae are the tubes that carry air directly to cells for gas exchange.
Spiracle are openings at the body surface that lead to tracheae that branch into smaller tubes known as tracheoles. Spiracles can open and close in order to prevent water loss.
Tracheoles have ends that are open and filled with liquid called tracheal fluid.

Insect at rest – not much metabolic activity, diffusion is adequate.




If the insect is very activeand needs a lot of energy, the tracheal fluid can be withdrawn to increase the surface area available to air. A larger surface area means a higher rate of oxygen diffusion (more oxygen absorbed every second).

When the insect is active and a faster rate of gas exchange is required, the also abdomen moves in order to ventilate the trachea

Here is the video of the locust dissection. Watch the whole thing for a good understanding of the locust. 











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