What is the Otic Vesicle
otic vesicle is surface ectoderm that sinks into mesoderm and therefore is the primordium of the saccule and utricle. Extensions from the saccule and utricle form the cochlear duct, semicircular ducts, and endolymphatic ducts.
Congenital atresia of the external acoustic meatus results from...
failure of the meal plug to re-canalize.
Where do hair cells come from?
Surface ectoderm of otic placode
What does the otic placode come from? What kind of tissue?
Surface ectoderm is influenced by mesoderm to form otic placode. This then becomes the otic vesicle
What do the auricles come from?
The auricular hillocks of the first and second pharyngeal arches fuse to form the auricle. Failure to properly fuse are commone
What happens to make the middle ear functional? What kind of hearing loss is induced if this doesn't occur?
Embedded in mesenchyme until the eighth month. Congenital fixation of the stapes causes conductive
What do auricular appendages come from?
Extra auricular hillocks.
What is microtia?
Small or rudimentary auricle
Describe the effects of rubella
Causes congenital deafness during weeks 7 and 8