BGDB Face and Ear - Late Embryo: Difference between revisions

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| [[File:Streeter1906 fig04.jpg|400px]]
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Growth and stages of differentiation of the human membranous labyrinth.
Embryonic development of the human membranous labyrinth.
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{{Med Prac additional Information}}
{{Med Prac additional Information}}


===External Auditory Meatus Timeline===


{| class="pretty table"
[[File:Streeter1906 fig04.jpg400px]]
|-bgcolor="CEDFF2"
 
| width=150px|'''Time'''
Growth and stages of differentiation of the human membranous labyrinth.
| '''EAM Appearance'''
|-
| Embryonic period
| Ectodermal cells proliferate and fill the entire lumen forming a meatal plug
|-
| 10 weeks
| Meatal plug extends in a disc-like fashion. In the horizontal plane the meatus is boot-shaped with a narrow neck and the sole of the meatal plug spreading widely to form the future tympanic membrane medially. Proximal portion of the neck starts to be resorbed.
|-
| 13 weeks
| Disc-like plug innermost surface in contact with the primordial malleus, contributes to the formation of the tympanic membrane.
|-
| 16.5 week
| Meatus is fully patent throughout its length, lumen is still narrow and curved.
|-
| 18 week
| Meatus is already fully expanded to its complete form.
|}


Based on data from PMID 1441991






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Revision as of 11:59, 16 May 2016

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Practical 6: Trilaminar Embryo | Early Embryo | Late Embryo | Fetal | Postnatal | Abnormalities


Week 6

Primary Palate

  • Beginning week 6 there is fusion of the upper lip.
  • Formed by the maxillary prominences of of the first pharyngeal arch and the frontonasal prominence.
  • Failure of this embryonic process leads to cleft lip.
  • Week 6 (stage 16)

    Week 6 (stage 16)

  • Week 6 (stage 17)

    Week 6 (stage 17)

  • Week 7 (stage 18)

    Week 7 (stage 18)

  • Week 7 (stage 19)

    Week 7 (stage 19)


Stage16-18 face.jpgBailey140.jpg

Above images show face development through week 6 to week 7 (1mm scale markings).

The animation shows the early fusion of the primary palate in the human embryo between stage 17 and 18, going from an epithelial seam to the mesenchymal bridge.

Face animation.gifFace Development Movie | MP4 movie

This animation shows a ventral view of development of the human face from approximately week 5 through to neonate.


The separate embryonic components that contribute to the face have been colour coded.

  • Frontonasal Prominence - frontal central (white)
  • Frontonasal Prominence - Lateral nasal (purple)
  • Frontonasal Prominence - Medial nasal (green)
  • Pharyngeal Arch 1 - Maxillary prominence (yellow)
  • Pharyngeal Arch 1 - Mandibular prominence (orange)
  • Stomodeum (black)

Week 8

  • Oral Cavity (stage 23)
  • Floor

    Floor

  • Floor (labeled)

    Floor (labeled)

  • Roof

    Roof

  • Roof (labeled)

    Roof (labeled)

Stage 22 image 159.jpg Stage 22 image 103.jpg

Stage 22 image 159.jpg Selected Head Images: B4 - Choroid Plexus | B5 - Cochlea | B6 - Cochlea


Palate

Stage 22 image 219.jpg The dark "pear-shaped" central structure at the top is the developing tongue. The two pale regions either side are the palatal shelves, note that they have not yet fused in the midline (failure of this process is cleft palate).

Hearing

Stage 22 image 219.jpg Behind that a pale cartilagenous region (that later ossifies) encloses the structuctures of the inner ear, beside which middle ear bones are forming. On the righthand side of the head the external ear is visible. The lower half of the image shows the developing brainstem with a large ventricular space occupied in part by an extensive choroid plexus (manufacturer of cerebrospinal fluid).
Stage 22 - Oral Cavity and Inner Ear

Stage 22 image 011.jpg

 ‎‎Mobile | Desktop | Original

Stage 22 | Embryo Slides
Streeter1906 plate01.jpg

Embryonic development of the human membranous labyrinth.

Streeter1906 plate02.jpg

Membranous labyrinth and acoustic complex model reconstructed from week 8 human embryo (CRL 30 mm). Note that by the end of the embryonic period the adult external structure has been achieved, internal development continues through the fetal period.

Embryonic External Ear

Shown below are the changes in external ear development between week 5 to week 8. Development changes from a series of 6 hillocks on arch 1 and arch 2 (week 5) to a structure resembling the adult ear (week 8).

External ear stages-14-23-adult.jpg


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Practical 6: Trilaminar Embryo | Early Embryo | Late Embryo | Fetal | Postnatal | Abnormalities


Additional Information

Additional Information - Content shown under this heading is not part of the material covered in this class. It is provided for those students who would like to know about some concepts or current research in topics related to the current class page.


File:Streeter1906 fig04.jpg400px

Growth and stages of differentiation of the human membranous labyrinth.



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BGDB: Lecture - Gastrointestinal System | Practical - Gastrointestinal System | Lecture - Face and Ear | Practical - Face and Ear | Lecture - Endocrine | Lecture - Sexual Differentiation | Practical - Sexual Differentiation | Tutorial


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Cite this page: Hill, M.A. (2024, April 16) Embryology BGDB Face and Ear - Late Embryo. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/BGDB_Face_and_Ear_-_Late_Embryo

What Links Here?
© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G
Retrieved from ‘https://embryology.med.unsw.edu.au/embryology/index.php?title=BGDB_Face_and_Ear_-_Late_Embryo&oldid=229017’
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