gas exchange Flashcards
what are the key systems of exchange
- lungs
- spiracles (tracheal system)
- gills
- skin breathing
gas exchange in animals
gaseous exchange occurs in the internal environment of most multicellular animals. The reason for this is that the exchange surfaces are highly specialised and could be easily damaged if outside the body.
what are the features of exchange surfaces
- moist
- thin and highly permeable
- large SA:VOL
- different concentrations outside the cell
describe how the exchange surface is moist
allows gases to dissolve in the water and diffuse from one side of the membrane to the other
describe how the exchange surface is thin and highly permeable
allow gas molecules a quick and easy passage
describe how the exchange surface has a large SA:VOL
allows for efficient diffusion into the cells
describe how the exchange surfaces have a different concentration outside the cell
maintains concentration gradient
describe the exchange surface in the lungs
the alveoli are small structures in the lungs where gaseous exchange. These thin, moist structures have alarge surface area, allowing for effective diffusion with the capillaries
describe the separation of surfaces
this separation ensures the protection of the exchange surfaces and also allows air to be cleaned on its way in.
describe gills
Most fish use gills to transfer gases. In this process, they take water in through their mouth and force it out and over their gills. The water flows over the lamella, structures rich in capillaries.
what are lamella
Are thin structures that are rich in capillaries and separate the water into many small streams, increasing the surface area.
describe skin breathing
Some terrestrial organisms are “skin breathers”, capable of transferring gases directly through their skin. However, due to the nature of exchange surfaces, they must live in damp and coll environments
describe spiracles
The tracheal system in insects relies on spiracles, which are openings at the body surface that lead to tracheae. The tracheae will branch into tracheoles which carry air directly to cells for gas exchange.
