Step I Cochlea - ectoderm?

[Phloston]

Hey, my exam's in 5 days. I'm not trying to be pedantic, but I am trying to iron out wrinkles.

P. 126 of FA2012 says "sensory organs of ear" for surface ectoderm.

What is that referring to exactly: the cochlea?

What about the ossicles? I know their arch #s, but would they be neural crest?

 

[Zzmed]

Yes, you 're right.

Pharyngeal arch skeletal and connective tissue components, all derive from cranial neural crest cells. Same goes for the ossicles.

''Sensory organs of the ear'' refers to everything that derives from the utricular and saccular portion of the otic placode, which derives from surface ectoderm. E.g. utricle, saccule, semicircular ducts, organ of Corti, vestibular and spiral ganglions of CNVIII etc.

 

[Phloston]

Thanks, bro.