Ureteric bud--metanephros or mesonephros?

[ChessMaster3000]

FA14 p. 522 says the ureteric bud is derived from the caudal end of the mesonephric duct. This is simple enough. However, I encountered a couple random questions that implied the bud, while still being derived from the mesonephric duct, is considered part of the metanephros. Basically, another name for ureteric but is the meTANEPHRIC diverticulum. This is so backwards--its called the metanephric diverticulum yet it is derived from the mesonephris.

Further, in FA, the ureteric bud is listed UNDER metanephros even though it is described as derived from mesonephros, which seems counter intuitive as well.

So my question is this--even though we know it is part of the mesonephric duct, is it still considered part of the mesonephros?

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[ulikedaggers]

The ureteric bud develops from the mesonephric duct. From the ureteric bud comes the metanephric blastema. The metanephric blastema and ureteric bud combined are the metanephros.

My understanding is that any permanent renal structure, including the ureters, is derived from the metanephros.

The mesonephros persists functionally only in the males. In females the mesonephric duct becomes the duct of gartner, and the mesonephric tubules become the paraoophoron and epoophoron.

 

[ChessMaster3000]

The ureteric bud develops from the mesonephric duct. From the ureteric bud comes the metanephric blastema. The metanephric blastema and ureteric bud combined are the metanephros.

My understanding is that any permanent renal structure, including the ureters, is derived from the metanephros.

The mesonephros persists functionally only in the males. In females the mesonephric duct becomes the duct of gartner, and the mesonephric tubules become the paraoophoron and epoophoron.

Don't you see the contradiction? You said the bud comes from the mesonphric duct, which is correct. Then you said metanephric blastema and ureteric bud comprise the metanephros. I think I am coming to understand that the metanephros is not a duct structure in the same way the mesonephros or even the pronephros is. It is a conglomerate of the metanephric mesenchyme (what you referred to as blastema, same thing), and the ureteric bud. While that make sense to me, if asked on the test what the ureteric bud is derived from, I'd have to say mesonephros. But if asked a different way, like what is the ureteric bud part of or something vague like that, then I am not sure what I would put.

 

[ulikedaggers]

Don't you see the contradiction? You said the bud comes from the mesonphric duct, which is correct. Then you said metanephric blastema and ureteric bud comprise the metanephros. I think I am coming to understand that the metanephros is not a duct structure in the same way the mesonephros or even the pronephros is. It is a conglomerate of the metanephric mesenchyme (what you referred to as blastema, same thing), and the ureteric bud. While that make sense to me, if asked on the test what the ureteric bud is derived from, I'd have to say mesonephros. But if asked a different way, like what is the ureteric bud part of or something vague like that, then I am not sure what I would put.

I can kind of see where you're coming from, but I don't think it's a contradiction. It's just another one of those name changes that crazy scientists like to do. The mesonephric duct gives rise to the ureteric bud so that the ureteric bud can contribute to the metanephros.

From where is the ureteric bud derived? Mesonephric duct.
What embryonic structure does the ureteric bud contribute to? Metanephros.
The embryonic precursor to the renal tubules is induced by what structure? Ureteric bud.