BGDB Face and Ear - Early Embryo
Practical 6: Trilaminar Embryo | Early Embryo | Late Embryo | Fetal | Postnatal | Abnormalities |
Week 4
During week 4 a number of features appear visible on the embryo surface:
- At the level of the body heart, liver, somite bulges and limb buds appear.
- At the level of the head sensory placodes and pharyngeal arches appear.
Carnegie Stage 12 to 14
Week 4
This is a scanning EM of the embryo superior dorsal view showing the paired otic placodes sinking into the surface at the level of the hindbrain between day 24 and day 25
Week 5
Sensory Placodes
Stage 13
Identify the structure and position of the otic vesicle (otocyst) relative to other head structures.
Stage 13 Movie - Overview of Head, Pharyngeal Arches and Pharynx
Pharyngeal Arches
Stage 13 Pharyngeal Arches
Section Images: A6L A7L B1L B2L B3L B4L B5L B6L
Look through the above cross-sections of the stage 13 embryo observing and identifying structures of the face and ear visible at this stage.
Structures derived from Arches
Arch |
Nerve |
Muscles |
Skeletal |
Artery |
(maxillary/mandibular) |
|
mastication |
Meckel's cartilage |
maxillary(terminal branches) |
(hyoid) |
|
facial expression |
Reichert's cartilage |
stapedial (embryonic) |
|
|
stylopharyngeus |
greater cornu of hyoid, lower part of body of hyoid bone |
common carotid, internal carotid (root) |
|
|
intrinsic muscles of larynx, pharynx; levator palati |
thyroid, cricoid, arytenoid, corniculate and cuneform cartilages |
4 - aortic arch, right subclavian |
Structures derived from Pouches
Pouch |
Overall Structure |
Specific Structures |
|
tubotympanic recess |
tympanic membrane, tympanic cavity, mastoid antrum, auditory tube |
|
intratonsillar cleft |
crypts of palatine tonsil, lymphatic nodules of palatine tonsil |
|
inferior parathyroid gland, thymus gland |
|
|
superior parathyroid gland, ultimobranchial body |
|
|
becomes part of 4th pouch |
Additional Information
|
|
Reference: <pubmed>14523380</pubmed>| Nat Rev Neurosci.
Practical 6: Trilaminar Embryo | Early Embryo | Late Embryo | Fetal | Postnatal | Abnormalities |
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, March 28) Embryology BGDB Face and Ear - Early Embryo. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/BGDB_Face_and_Ear_-_Early_Embryo
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G