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Developmental Anatomy

Stage 14: Summary

External view Internal view

External: Invagination of the lens disc but with an open lens pit; a well-defined endolymphatic appendage; elongated and tapering upper limb buds.

Internal: The ventral pancreas (if not detectable earlier) is distinguishable at stages 14 and 15; right and left lung sacs grow dorsad; the ureteric bud acquires a metanephrogenic cap; future cerebral hemispheres and cerebellar plates begin to be visible.

Lab Manual - Horizon 14 (CC#6848)

First view

  • Length: 5 - 7 mm.
  • Invagination of optic lens.
  • Ear vesicle has well-defined endolymphatic appendages.
  • Mandibular and hyoid bars have acquired ascendancy over third or gloss pharyngeal bar.
  • Arm buds elongating and curved toward body.
  • Leg buds are fin-like.
  • Ovulation age: 31 - 35 days.

Stage 14: Animation

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Developmental Stages in Human Embryos by Ronan O'Rahilly and Fabiola Müller.
Published by Carnegie Institution of Washington, Publication 637. 1987.

Stage 14 (PDF 1 MB)

 

QUESTION: What structure becomes well defined in the ear vesicle?