Tracheal System In Insects

Question 1

Ways in which respiratory gases move in and out of the tracheal system

Answer 1

• O2 diffuses from the spiracle towards respiring tissues
• CO2 diffuses from respiring cells to spiracles
• (abdominal pumping) - contraction of muscles - air sacs
• muscle cells respiring anaerobically
• lactic acid is produced
• water potential lowers in the muscle cells
• water exits ends of tracheole via osmosis

Question 2

Limitations of the tracheal system in insects

Answer 2

Length of diffusion pathway limits the size of that insects can attain

Question 3

How us an insect’s tracheal system adopted for efficient gas exchange?

Answer 3

• large numbers of tracheoles so short diffusion distance to cells
• fluid in the end of tracheoles that moves out (into tissues) during exercise so faster diffusion through the air to the gas exchange surface
• abdominal pumping

Question 4

In insects, why does the trachea not collapse?

Answer 4

They are supported by strengthened rings made of collagen

Question 5

Differences between the trachea and tracheoles

Answer 5

• tracheoles are much smaller dead end tubes which the trachea divides into
• tracheoles are much smaller - end in respiring tissue

Question 6

Differences between the stomata and spiracles

Answer 6

• stomata is the opening between guard cells, whereas spiracles are the opening of the trachea
• the stomata are found in plants whereas spiracles are found in insects
• the stomata are usually found on the leaves of plants, whereas the spiracles are usually found on the abdomen of insects