[munificent]

Assuming we can ignore your septum and the roof of your mouth, your respiratory system is basically just an indentation in your head. From a topology perspective, it doesn't really exist. Your lungs are on the outside.

[apr]

But that's the thing, you cannot ignore those parts in topology. Even if they look small compared to the rest of the body.

[munificent]

Sure, but you could still be a functioning human without them. You'd be a mouth breather, but you could survive.