What is the difference between spiracles and trachea

Tracheae open to the outside through small holes called spiracles. In the grasshopper, the first and third segments of the thorax have a spiracle on each side. Another 8 pairs of spiracles are arranged in a line on either side of the abdomen.

Spiracles open into large tracheal tubes. These, in turn, lead to ever-finer branches. The branches penetrate to every part of the body. Every cell in the insect's body is adjacent to, or very close to, the end of a tracheole.

In some of the flight muscles of Drosophila the tracheoles even penetrate their T-tubules bringing oxygen right next to the mitochondria that power the muscle. This photomicrograph show how the walls of the tracheal tubes are stiffened with bands of chitin.

Even so, there is a limit to the pressure they can withstand without collapsing. This may be one reason why insects are relatively small. The increased weight of the tissues of an animal the size of a rabbit, for example, would crush tracheal tubes filled only with air. In general, the size of the tracheal system increases with age in order to support the increased gas exchange needs of the larger insect.

Major changes in tracheal structure, including changes in spiracle number and tracheal system organization, can occur at each molt and during the pupal period for endopterygote insects. The organization of the tracheal system varies dramatically among insects, with spiracle number ranging from 0 to 20 and with tracheal branching patterns varying widely across species, between body regions, and during the developmental stages of holometabolous insects.

Tracheal System. N2 - This chapter describes tracheal system of insects. AB - This chapter describes tracheal system of insects. Overview Fingerprint. Abstract This chapter describes tracheal system of insects. Access to Document Link to publication in Scopus. Fingerprint Dive into the research topics of 'Tracheal System'.

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