Special Senses Flashcards
what does the enoderm into the rhombencephalon form
otic placode
what week does development of the semicircular canal occur
during Week 6
what is the ampulla
dilated end on the semicircular canal
what does the crista ampullae contain
what are these for
sensory cells
balance
what are the fibres of the ampullae
vestibular fibres of cranial nerve 9
when does the spiral of the tubular part occur
6 - 8 weeks
what does the left over cochlear duct do
communicates with the saccualr
what is the lining of the duct called
what is it formed by
neurepitheloium
the organ of corti
what is the function of organ of corti
functional unit of sound
what happens to the organ of corti
whole structure vaculosies into two aras
what happens to the cochlear duct
circular to triangular
what happens to the basement membrane
all uniform - then some start to lengthen and become more columnar then the side attached to the spiral ligament and close to the scala vestibuli are no longer membrane but rather vesticular membrane
what happens to the scala tympani and the scalal vestibuli
these valculise and become hollow chambers
what happens to the spiral ligament
it appear then it becomes larger
what is the modiolus
bony structure it is the part between the scala vestibuli and the scala tympani
what goes into the scala vestibuli and the scala tympani
extracellular fluid ech slightly different
what are the outer ridge and inner ridge of the epithelial part
INNER FORMS A SPIRAL LIMBASE AND CONNECTS TO THE TECTORAL MEMBRANE (black bit)
outer is a hair like structure
what two arches makes the middle ear
first and second
what happens around the auditory ossicles
condensation occurs and the mesnhyme around the cartilgaous precuros will degrade to form a cavity (enodericmal lining)
how is the tympanic membrane formed
invagination of the ectoderm will start to join the endodermal projection
when the mesnehyme goes away what is left
some ligament attach to allow mvoement
how is the metal plug formed
month
epithelial cells proliferate to form the meatal plug
what happens to the plug at month 7
dissolves and contributes to the eardrum
