Random question about the exhaust

[Jeff4runner]

This probably seems like a dumb question, but I never really figured it out. On the exhaust pipes, you have the muffler (I have the magnaflow), the cat, then these bulges right on the exhaust headers, then one on the very back tailpipe. Are these additional mufflers/cats? Or really wierd design things by toyota?

 

[fourwd1]

I think you're talking about the flex joints. They compensate for movement between the engine/exhaust/frame.

 

[Burt]

I think the two "bulges" front are the CATS and the one in very rear is a "resonator".