Exchange in Insects Flashcards
How do single celled organisms obtain substances?
through diffusion across their surface
Why do single celled organisms not require an exchange surface?
they have a large surface area:volume
What effect does a cell wall have on the diffusion of gasses in a single celled organism?
no effect
What is the internal network of tubes in an insect called?
tracheae and tracheoles
How are tracheae supported to prevent collapse?
they have strengthened rings around them
How do tracheoles ensure a short diffusion pathway?
athey bring air directly to the respiring tissues
State 3 ways that respiratory gases move in and out of the tracheal system
diffusion along a gradient
mass transport
water in the ends of tracheoles
Describe how a diffusion gradient in created in the tracheoles
oxygen diffuses into the respiring cells resulting in a lower concentration than in the air
How do insects use mass transport to move air
they contract muscles that squeezes the trachea
What happens in the cells around tracheoles during major activity?
anaerobic respiration produces lactate
What does lactate production do to the water potential in the muscle cells
reduces it
What happens to water movement in tracheoles during major activity in insects?
it moves by osmosis from high water potential in tracheoles to lower water potential in cells
How does movement of water from tracheoles to cells affect gas exchange?
lower pressure draws air further in which then diffuses more rapidly into cells
Name the point of air entry into an insect
spiracles
How do insects reduce water loss through spiracles?
they close them using a valve
