Gas Exchange: Insects Flashcards
What is the most common gas exchange arrangement in insects?
Tracheal systems.
What is the relationship between the size of an organism and the surface area : volume ratio?
The smaller an object is, the greater the SA : V ratio.
A single celled organism such as paramecium gains oxygen and removes carbon dioxide through what process?
Simple diffusion.
Why cannot insects use simple diffusion to gain oxygen and lose carbon dioxide?
Due to the waxy exoskeleton.
How does air move into the tracheae?
Through pores on the surface called spiracles.
What are tracheae?
They are microscopic air-filled pipes used for gas exchange.
How do insects move air in and out of the spiracles?
Through rhythmic abdominal movements.
What are the three main features of the tracheal system?
Trachea, Tracheoles and Spiracles.
Explain the results of the insect flying on respiration:
The muscle cells start to respire anaerobically producing lactate. This lowers the water potential of the cells and therefore water moves from the tracheoles into cells by osmosis. This decreases volumes of tracheoles and more atmospheric air is drawn in.
What minimises water loss from an insect?
The waxy cuticle as it is impermeable to water.
What is the downside of having a waxy cuticle in terms of gas exchange?
It is also virtually impermeable to gases as well as water.
What system do insects use to exchange gases?
The tracheal system.
What are spiracles?
Holes in the cuticle that allow air in and out of the body.
What causes changes in the opening of spiracles?
Carbon dioxide levels.
If a high carbon dioxide level is detected, what will happen?
The spiracles are open.
What molecule lines the tracheoles?
Nothing, they are unlined.
What do the trachea lead to?
The tracheoles.
What is the name for the first tubes which the spiracles lead into?
Trachae.
The walls of the trachea are lined with Chitin, what is the function of this?
Supports them and makes them impermeable to gases.
Where does gas exchange occur?
Tracheoles.
How does the trachea allow the respiratory system to work independently of the circulatory system?
The blood has no direct role in transporting respiratory gases.
The walls of the trachea are lined with what?
Chitin, which supports them and makes them impermeable to gases.
How does air move down the tracheal system?
In smaller or more inactive insects gases use simple diffusion. In larger or more active insects air can be actively pumped by the thorax or abdomen.
What stimulates spiracles to open?
High levels of carbon dioxide.
