Template:Human embryo Hertwig G31 table

From Embryology
Human Embryo G31
Collection of Prof. O. Hertwig, Anat-biol. Institute, Berlin.Carnegie stage 14
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
14 Human embryo G 31. N.T. Fig. VIII. Text-fig. 12a-12p. Gr. L. = nape-breech length, 4.9 mm. vertex-breech length 4.7 mm. Greatest diameter of yolk sack 0.58 mm Supposed to be 4 weeks. Between Figs. 6 and 7 of His' Normentafel, nearer Fig. 7. Vanished up to the tail bud. 35 pairs of primitive segments, the most anterior quite rudimentary. The anterior end terminates close to the hypophysis. Very thin chord sheath. Infundibulum. Roof of the 4th ventricle thin. 7 distinct neuromeres in 4th ventricle region. No dorsal columns in spinal cord as yet. Neuroenteric cord. Transition from optic vesicle to otic cup. Lens represented by thickened area of ectoderm,. Scattered mesenchyme cells between lens and otic vesicle. Auditory vesicle just constricted off. The point of constriction still visible at the ectoderm. Ductus endolymphaticus just formed. Distinct convex olfactory areas. Very broad hypophyseal pouch. No remains of pharyngeal membrane. Tuberculum impar. Stomach anlage already slightly twisted. Tail gut. Abundant trabeculae in liver anlage. Gall-bladder formed. Distinct anlage of dorsal pancreas. Early anlage of ventral pancreas. (Jankelowitz 1895 describes 2 ventral pancreas anlagen. Itis doubtful if there are really two; it seemed to us that there was only one.) 4 branchial pouches reach the ectoderm. The solid, two-lobed anlage of the median thyreoid is connected with the floor of the Trachea constricted off. Undivided bronchial buds. Wolffian duct interrupted cranially, free glomeruli right and left ("pronephric remains"). In the mesonephros anlage of glomeruli, caudally segmental vesicles, partly with rudimentary nephrostomes. Wolffian ducts have reached the cloaca, but do not yet open into it. Very early anlagen of the metanephric buds as enlargements of the Wolffian ducts. Nephrogenic cord. Cloaca with bladder and intestinal bay. Primitive germ cells. Atrial and ventricular septum formed, also the right valvular venous. Primary origin of the aa. umbilicales. The aa. omphalo- mesentericse form a ring around the in- testine. Vv. om- phalo-mesenteri- cae connected by an anastomosis dorsal to the intestine. Upper extremity plate-like, lower one like a swelling. Numerous fresh mitoses.
Remarks - Fixation: (according to Herr, 1893) sublimate- acetic acid ; (according to Jankelowitz, 1895 picric-sublimate-acetic acid. Stain: Borax carmine- aurantia. Sections: 10 μ, trans. The embryo was modelled by Dr. Ingalls, compare Irgalls (1907). Literature: Herr, Beitrag zur Entwicklungageschichte des menschl. Auges. Dissert. Berlin, 1893. Jankelowitz, Zur Entwicklung der Bauch- speicheldruse. Dissert. Berlin, 1895. Also, Ein junger menschlichen Embryo, etc. Arch, f mikr. Anat., Vol. 46, 1895.—O.Hertwig, , LehrbuchderEntwicklungsgeschichte. Also, Elemente der Entwick- lungslehre, 3rd ed., 1907. —Ingalls, N. W., Beschreibung eines menschl.

Embryo, etc., Arch. f. mikr. Anat., Vol. 70. 1907. Bursa omentalis, with foramen of Winslow, is formed.

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

Ingalls NW. Description of a human embryo of 4.9 mm (Beschreibung eines menschlichen Embryos von 4.9 mm). (1907) Arch. f. mik. Anat., 70: 506-576.

1908 Embryo Tables: Klb (stage 10) | Pfannenstiel III (stage 11) | Meyer 300 (stage 12) | Strahl 4mm (stage 13) | Hertwig G31 (stage 14)