Template:Human embryo Meyer 300 table
From Embryology
Human Embryo No. 300 | ||||||||||||||||||||||
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Collection of Professor R. Meyer, Berlin. Carnegie stage 12 | ||||||||||||||||||||||
Desig. | Size | Age | Body form | Primitive streak | Primitive segments | Chorda | Nervous system | Eye | Ear | Nose | Hypophysis | Mouth | Digestive trac, liver and pancreas | Branchial pouches, threoid thymus, trachea and lungs | Urogenital system | Heart and vessels | Integument | Skeleton | Extremities | Amnion | Allantois | Remarks |
7 N.T. Fig. VI 1, VI r ind VI v. |
Gr. L. 2.5 mm. | Remains of primitive streak. Cloacal membrane. | 23 pairs of primitive segments. | Chorda separated from entoderm, | Anterior neuropore closed. but its position still recognizable. Medullary canal stili wide open for a stretch caudally. Roof of 4th vent, beginning to thin out. Neuromeres. Trigeminus and acustico-facialis ganglia distinct. | Optic vesicles. Mesoderm between ectoderm and optic vesicle, | Auditory vesicle almost closed (open through 4 or 5 sections of 5μ). Ductus endolymphaticus not yet visible. | Anlage doubtful. | Pharyngeal membrane just torn, still abundant remains of it. | Intestine still communicates widely with the yolk sack. Liver a thick-walled sack from which the trabeculse are beginning to bud. | The 3 anterior branchial pouches reacts the ectoderm; the 4th, though formed, does not. Thyreoidea mediana formed. Pulmotracheal groove. The paired condition of the pulmonary anlage already indicated. | Rudimentary "pronephric anlage" | Heart S-shaped. | Allantoic duct | The embryo was obtained by operation. | |||||||
Remarks
Abundant mitoses in the embryo. Fixation: ? Stain: Borax carmine. Sections: 5 μ. The embryo was modelled by Dr. Peter Thompson (1907) Also see Meyer (1904) | ||||||||||||||||||||||
Reference: Keibel F. and Elze C. Normal Plates of the Development of the Human Embryo (Homo sapiens). (1908) Vol. 8 in series by Keibel F. Normal plates of the development of vertebrates (Normentafeln zur Entwicklungsgeschichte der Wirbelthiere) Fisher, Jena., Germany. Cited in: 1912 Human Embryology and Thompson P. Description of a human embryo of twenty-three paired somites. (1907) J Anat Physiol, 41(3):159-71. PMID 17232726; Meyer, Rob., Ueber die Beziehung der Umierenkanalchen zum Coelomepithel, etc., Anat. Anz., Vol. 25, 1904 | ||||||||||||||||||||||
1908 Embryo Tables: Klb (stage 10) | Pfannenstiel III (stage 11) | Meyer 300 (stage 12) | Strahl 4mm (stage 13) | Hertwig G31 (stage 14) |