Gas Exchange In Insects Flashcards
Why do insects not have lungs
Because they are so small and have a large surface area to volume ratio
What do insects have instead of lungs
Spiracles
What are spiracles
Small holes that cover an insects entire body - besides the head
What is the process of gases exchange in insects
Air enters through the spiracles
It travels down the tracheal tubes
The tubes branch off into tracheoles
The tracheoles lead to individual cells
How do insects overcome not having a circulatory system
The oxygen in the air moves down the concentration gradient and diffuses straight into cells so that they can do respiration
How else can insects move air in and out of the spiracles
Through rhythmic abdominal movements
How does rhythmic abdominal movement work
The contacting of muscles in different segments of the body allows gases to be pumped in and out of the body
Can insects choose to open or close particular spiracles? What can this do?
Yes, they can choose to open and close particular spiracles, this can effectively suck air in one end and let it out the other
What can closing spiracles help with? What is this similar to
Not losing as much water, this is similar to the stomata in plants
When do spiracles close? Give an example
When the insect is inactive
Eg when stood still or when sleeping some spiracles close
How is the body surface of a single celled organism adapted for gas exchange
It has a thin, flat shape and a large SA:Vol ratio
It has a short diffusion distance to all parts of the cell so diffusion of O2 and CO2 is quick
What do insects have to adapt for gas exchange
Tracheoles have thin walls
High numbers of highly branched tracheoles
Tracheae provide tubes full of air
Contraction of abdominal muscles
Fluid in ends of tracheoles
How does thin tracheole walls help as an adaptation for gas exchange
Means the diffusion distance to cells is small
How does high numbers of highly branched tracheoles help as an adaptation for gas exchange
Gives a short diffusion distance to cells
Gives a large surface area for diffusion
How does tracheae providing tubes full of air help as an adaptation for gas exchange
Helps with fast diffusion
How does contraction of abdominal muscle help as an adaptation for gas exchange
The contraction changes the pressure in the body, causing air to move in or out
This maintains a concentration gradient for diffusion
How does fluid in the end of tracheoles help as an adaptation for gas exchange? How is it drawn in to the end of the tracheoles
Fluid is drawn into tissues by osmosis during exercise - lactate produced in anaerobic respiration lowers the water potential of cells
As fluid is removed, air fills the tracheoles so the rate of diffusion to gas exchange surface increases as diffusion is faster through air
Why are some structural and functional compromises in terrestrial insects that allow efficient gas exchange whilst limiting water loss
Thick waxy cuticle/exoskeleton
Spiracles can open and close
Hairs around spiracles
How does a thick waxy cuticle in a terrestrial insects allow for efficient gas exchange while limiting water loss
Increases the diffusion distance, so less water is lost through evaporation
How do spiracles in a terrestrial insects allow for efficient gas exchange while limiting water loss
They can open to allow gas exchange and close to reduce water loss through evaporation
How does a hairs around the spiracles in terrestrial insects allow for efficient gas exchange while limiting water loss
The hairs trap moist air, reducing the water potential gradient so there is less water loss by evaporation
