what is the meaning of the following expressio?

[john3_10]

spiracle barrier

i have heard it from bleach episode 24

[pyoung]

spiracle barrier

i have heard it from bleach episode 24

Dear john 3:10:

A spiracle is an air hole, such as a whale has in the top of its head. Other species possess this mechanism as well.

One reference explains that:

The spiracle of Ixodes ricinus (L.) (Ixodidae: Metastigmata: Acarina): a passive diffusion barrier for water vapour.

I hope this is helpful.

Petra