Insects Flashcards
What are the 5 features of a good gas exchange system?
- Moist and warm environment
- Large sa:v ratio
- Partially permeable
4.very thin so diffusion distance is short - Movement of environmental medium and internal medium
What is one of the biggest problems for terrestrial animals?
Dehydration so they need to conserve water
What adaption do insects have to reduce water loss?
Outer skeleton is covered with a waterproof cuticle
Why do insects have a low SA: vol ratio?
Minimise the area which water is lost
what are tracheae and what is their role?
Tubes that penetrate inside the body, carrying air into every tissue
What do tracheae branch into?
Smaller tracheoles
What are spiracles?
Openings at the body surface that leads to tracheae that branch into smaller tracheoles
What is the role of spiracles?
Close to prevent water loss, but can be opened to allow gas exchange
What is abdominal pumping?
Body movements or contractions speed up the rate of diffusion of gases from tracheae into body cells.
How is a diffusion gradient maintained by tracheoles?
The oxygen is used at the end of the tracheoles
What adaptations do insects have that allow for efficient gas exchange?
- The wall at the end of each tracheole is only one cell thick which allows for a short diffusion pathway
- tracheoles are highly branched and in large numbers which provides a large surface area for gas exchange and short diffusion pathway
- muscle contraction moves large amounts of air through tracheae and tracheoles which maintains a conc gradient of O2 and co2
- the ends of tracheoles are filled with fluid. Muscle contractions move this fluid into surrounding tissue. This causes air to be drawn into the tracheoles. As diffusion through air is quicker than through liquid this allows faster diffusion into the tissue
what is the main site of gas exchange in insects?
Tracheae
