Eustachian tube - endoderm or mesoderm?

[Phloston]

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A bit confused here because p. 126 of FA lists it as mesoderm, but p. 137 lists it as a POUCH derivative, which refers to endoderm. And of course Googling tells me nothing. Does anyone know? Unless the tube itself is mesoderm but the LINING is endoderm? Regardless, it would be nice to have a clear answer.

And a side note:

Is the bladder endoderm, except the trigone is mesoderm?

P. 126 lists bladder as mesoderm, but I had thought the above statement.

Thanks,

 

[MedPR]

What kind of schedule are you on that you're taking Step 1 in December? Typical for MD/PhD students?

 

[dancingDO14]

From FA errata:

(1) The bladder, urethra, lower 2/3 of the vagina, and the eustachian tube are derived from endoderm, not mesoderm.
(2) Only the upper 1/3 of the vagina is derived from mesoderm.

 

[image187]

From FA errata:

(1) The bladder, urethra, lower 2/3 of the vagina, and the eustachian tube are derived from endoderm, not mesoderm.
(2) Only the upper 1/3 of the vagina is derived from mesoderm.

are you sure thats not supposed to say "Fallopian tube"? why the hell would they be talking about the eustachian tubes given the context of the rest of the sentence? Thats gotta be a typo... but who knows, definitely double check that

 

[Zzmed]

All first pouch derivatives (middle ear cavity, eustachian tube, mastoid air cells) derives from endoderm. Period.
BUT first aid in pg 137 says that ''1st pouch contributes to endoderm-LINED structures of the ear''. Ok.. I want to believe that they mean the above...
But eustachian tube is, for sure, from endoderm.

As far as the bladder is concerned... definitely endoderm.
!BUT note that this is correct only if we speak for the transitional epithelium of the bladder. The muscles of the bladder (detrusor and sphincter) derive from mesoderm as all muscles (smooth, cardiac, skeletal)! ----> So, what Phloston says, about the lining of some organ parts it is kinda true if you give it some thought...

 

[dancingDO14]

are you sure thats not supposed to say "Fallopian tube"? why the hell would they be talking about the eustachian tubes given the context of the rest of the sentence? Thats gotta be a typo... but who knows, definitely double check that

Not a typo. Genitals develop from mesoderm. The errata is only fixing one sentence of the Endoderm section, which reads, with the correction, "Gut tube epithelium (including anal canal above the pectinate line) and derivatives (e.g., lungs, liver, pancreas, thymus, parathyroid, thyroid follicular cells), lower 2/3 vagina, bladder, eustachian tube."

Zzmed, I think you are spot on. 👍