Insect and Fish Gas Exchange Flashcards
(30 cards)
What is the name for the outer structure of an insect?
Exoskeleton
What biomolecule is the the outer surface of an insect made from?
Why?
Lipids. Prevent water loss.
Name the gas exchange system used in insects.
Tracheal
What are spiracles?
Holes in the insects exoskeleton that enables them to respire. Allows for entry of air.
What are trachea?
Tubes that make up the insect respiratory system.
Why are the trachea lined with chitin?
To prevent them from collapsing
What are tracheoles?
Sub divisions of smaller tubes off of the trachea. They extend throughout the insect to tissues and cells. They do not contain chitin.
How is a steep diffusion gradient maintained for O2 in insect gas exchange?
O2 used up by body cells so the concentration gradient in tracheoles falls. The low concentration of O2 here allows more to diffuse in.
How is a steep diffusion gradient maintained for CO2 in insect gas exchange?
CO2 a product of respiration, so conc is high in the trachea. It diffuses out of the tracheoles , where conc is lower.
What happens to tracheoles when the insect is at rest or when it is flying?
They fill with water.
- INSECT GAS EXCHANGE How do muscle cells in the insect respire when the insect is flying or at rest?
They respire anaerobically.
- INSECT GAS EXCHANGE
What substance is produced during anaerobic respiration in insects?
Lactate
- INSECT GAS EXCHANGE
Does production of lactate causes the water potential of cells to higher or lower?
Lower
- INSECT GAS EXCHANGE
Lower water potential of body cells causes water to move where?
Water moves into tracheoles by osmosis.
- INSECT GAS EXCHANGE
What happens when water starts to decrease in tracheoles?
More air is drawn into them
Which state is the diffusion pathway in in insects?
How does this benefit diffusion?
Gas - This increases the rate of diffusion.
What are the benefits/costs in insect gas exchange?
Rate of airflow is higher but more water is lost.
What are the benefits of having a large number of tracheoles?
They give a large surface area.
What are the benefits of the tracheole walls being thin?
Short diffusion pathway.
In larger insect species, what do they have instead of trachea reinforced with?
Collapsible air sacs, which are inflated by movement of the abdomen.
How can water loss be reduced in insects?
Spiracles can be opened and closed periodically.
What are the issues with the insect gas exchange system?
Relies on diffusion of gases
The length of the diffusion pathway limits the size that insects can attain
Do fish have a small or large SA:Vol ratio and why?
Small SA:Vol ratio due to the large size of the organism.
Name the system that fish have for gas exchange.
Internal gill system.
