Term
| What happens during the third week of development? |
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Definition
-Inner ear: auditory placode and auditory pit form
ME: Tubotympanic recess begins to develop
-OE: auricle starts to develop from 1 and 2nd arches |
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Term
| What happens in the 4th week of development? |
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Definition
IE: Auditory otocyst develops into utricular-saccule area & tubular extension known as endolymphatic ducts then the auditory otocyst is becoming future vestibular part of labyrinth & skinny part of otocyst begins to get longer & will become the cochlea
-ME: 4th wk: 5 branchial grooves or “gill slits” are on head & pharyngeal pouches develop inside of embryo
-OE: tissue thickening begins to form |
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Term
| What happens in the 5th week? |
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Definition
| ME: Primary auditory meatus begins |
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Term
| Whats happens during the 6th week? |
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Definition
IE: utricle and saccule present and the semicircular canals begin
ME: nothing
OE: The six hillocks are evident and the cartilage begins to form |
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Term
| What happens during the 7th week? |
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Definition
IE: one cochlear coil is present, otic labyrinth keeps developing,
epithelial thickenings develop into sensory cells & supporting cells at one end
-ME: nothing
-OE: The auricle starts to develop but won't finish until week 20 |
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Term
| What happens during the 8th week? |
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Definition
-IE: The ductus reuniens are present and the sensory cells in the SC are still forming
-ME: Incus and malleus are present in cartilage and the lower half of the tympanic cavity is formed
-OE: Outer 1/3 cartilaginous portion of external canal is formed |
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Term
| What happens during the 9th week? |
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Definition
| ME: three tissue layers (inner circular, fibrous middle layer, and outer radial fiber layer) become TM |
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Term
| What happens during the 11th week? |
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Definition
| IE: 2.5 cochlear turns are present and the 8th nerve attaches to cochlear duct |
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Term
| What happens during the 12th week? |
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Definition
| IE: Sensory cells in cochlea are developing, the membraneous labyrinth is complete, and the otic capsule begins to ossify |
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Term
| What happens during the 15th week? |
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Definition
| ME: Cartilagionus stapes formed |
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Term
| What happens during the 16th week? |
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Definition
| ME: Ossification of malleus and incus begins |
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Term
| What happens during the 18th week? |
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Definition
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Term
| What happens during the 20th week? |
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Definition
IE: maturation of IE-the IE is adult size
ME: nothing
OE: auricle is adult shape but continues to grow until age 9 |
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Term
| What happens in the 21st week? |
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Definition
| ME: meatal plug disintegrates, exposing TM |
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Term
| What happens during the 30th week? |
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Definition
ME: pneumatization of tympanum
OE: external auditory canal continues to mature until age 7 |
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Term
| What happens in the 32nd week? |
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Definition
| ME: malleus and incus complete ossification |
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Term
| What happens in the 34th week? |
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Definition
| ME: mastoid air cells develop |
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Term
| What happens in the 35th week? |
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Definition
| ME: antrum is penumatized |
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Term
| What happens in the 37th week? |
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Definition
| ME: epitympanum is pneumatized, stapes continues to develop until adulthood, and TM changes relative to position during first 2 years of life |
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Term
| develop outer skin layers, nervous system, & sense organs |
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Definition
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Term
| develop skeletal & circulation structures, kidneys, reproductive organs |
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Definition
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Term
| develop digestive & respiratory organs |
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Definition
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Term
-Middle ear ossicles & bone around inner ear develop from ___
-Outer & inner parts of ear develop from ___ |
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Definition
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Term
| Early development: cells differentiate into __ superimposed germ layers. At first, cells on all layers are the ___, but ___ changes make distinct layers |
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Definition
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Term
Growth of Embryo Week 2:
-cellular disc has __ germ layers
-primitive streak splits embryonic disc, which leads to primitive ___ (lined with ectoderm) & primitive ___ |
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Definition
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Term
Growth of Embryo Week 2:
-Primitive groove deepens into primitive pit that becomes
the neural ___ & neural ___
-Neural folds come together to close off ___ ___ (a.k.a.
neural tube a.k.a structure that forms the brain and spinal
cord)
-Primitive knot (at end of primitive streak) becomes the ___ |
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Definition
| groove; fold; neural groove; head |
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Term
IE:
-The inner ear is derived from a pair of ___ ___ that appear in human development during week 4 in the head region lying behind the ___ pharyngeal arch.
-These otic placodes fold ___ forming initially a depression, then pinch off entirely from the surface forming an ___ surrounding a fluid-filled sac or vesicle (otic vesicle, otocyst, auditory vesicle). The vesicle ___ into the head mesenchyme some of which closely surrounds the otocyst forming the otic capsule.
-The otocyst finally lies close to the early developing ___ and the developing ___-___-___ ganglion complex.
-The otocyst epithelium then undergoes a series of morphological changes, forming the primitive membranous ___. During the human fetal period this will differentiate into the inner ear components for hearing (___) and balance (___ ___). |
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Definition
| otic placodes; second; inwards; epithelium; sinks; hindbrain; vestibulo-cochlear-facial; labyrinth; cochlea; semi-circular canals |
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Term
| What happens in the IE at the end of the 6th week? |
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Definition
| arch-like pouches will become semi-circular canals, utricle & saccule become 2 different areas |
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Term
ME:
-3rd week: ME ___ starts to develop while auditory pit is
becoming ___ ___
-1st pharyngeal pouch (lined with endoderm) gets longer & becomes the ___ ___ & the ___ ___ (which becomes Eustachian tube later)
-Tubotympanic recess: elongated part of the ___ pharyngeal puch |
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Definition
| cavity; auditory vesicle; tympanic cavity; auditory tube; first |
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Term
4th week of ME development:
-grooves & pouches are “___”
-one of the gill pouches perforates, makes channel from pharynx to outside of head that becomes ______ and ___ ___
-___ ___ forms |
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Definition
| arches; EAC & eustachian tube ; TM |
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Term
ME development:
-8th week: ___ ___ is present in future middle ear,
upper ½ is filled with mesenchyme
-8.5 wks: ___ and ___ reach adult form, stapes develops
until week ___ |
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Definition
| tympanic cavity; incus & malleus; 15 |
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Term
-The external ear is derived from __ surface hillocks,
three on each of pharyngeal arch 1 and 2
-The external auditory meatus is derived from the ___ pharyngeal cleft |
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Definition
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Term
OE and TM:
-3rd-4th week: auricle develops from __ and __ branchial arches
-auricle is mostly from ___ branchial arch (forms when auditory vesicle forms in inner ear)
-4th-5th wk: _______ develops from 1st branchial groove
-Ectoderm of 1st branchial groove touches ___ of 1st pharyngeal pouch & ___ grows between 2 layers to separate pharyngeal pouch from branchial groove |
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Definition
| 1st & 2nd; 2nd; External auditory meatus; endoderm; mesoderm |
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Term
Meatal plug keep EAC closed until wk __, then disintegrates
& forms canal; EAC develops until age __ years |
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Definition
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Term
| is a tubercle seen along the upper, posterior portion of the helix |
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Definition
Darwin's Tubericle
[image] |
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Term
Associated with Fetal Alcohol Syndrome, the curve at the top part of the outer ear is underdeveloped and folded over parallel to curve beneath
[image] |
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Definition
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