File:Pohlman1911 plate3E.jpg

From Embryology

Original file(1,988 × 1,895 pixels, file size: 198 KB, MIME type: image/jpeg)

Plate 3E

Model E. {No. 19; Mall no. 221; 12.0 mm.) This stage shows the cloaca about half divided along the furrow line indicated in Model A. The cloacal membrane has thickened but mostly through addition of ectodermal cells, and has been displaced through development of the ' precloacal mesoderm' from its primitive position parallel to the dorsal line of the cloaca to one more nearly at right angles to it. In so far as it was possible to ascertain, this downward displacement of the cloacal membrane in no way affects its caudal limit. The dorsal segment has retained the original proportions while the ventral segment has widened - most marked again at the level of the Wolffian orifices. The further development of the kidney and ureter will be noted and the gradual approach of the ureteral orifice to the cloaca proper is evident. The ureter shows signs of shifting from its primitive dorsal position on the Wolffian duct to a more lateral one. The peritoneum has descended to the level of the ducts while the cloacal division is relatively far advanced. The model agrees with Keibel's model of an 11.5 mm. embryo.


No. 19 (Mall 221; 12.0 mm.; = ; 20; Good). Model E x 100. All traces of tail gut lost. Cloacal membrane somewhat depressed from surface. Cloacal segment of Wolffian duct shortened and opening of ureter and duct common into ventral cloacal segment. Beginning formation of genital eminence and lengthening of the ventral cloacal wall. Cloacal membrane intact. Carnegie stage 16


Stage 16 Links: Week 6 | Head | Lecture - Limb | Lecture - Gastrointestinal | Lecture - Head Development | Science Practical - Gastrointestinal | Science Practical - Head | Carnegie Embryos | Category:Carnegie Stage 16 | Week 6 | Next Stage 17
  Historic Papers: 1906 | 1908 | 1948 stages 15-18


Week: 1 2 3 4 5 6 7 8
Carnegie stage: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23


Key to Lettering

A., Allantois

K., Kidney

A.M., Position of anal membrane

P.T., Precloacal mesodermic tissue

C., Cloaca

R.B., Renal bud

CM., Cloacal membrane

T.G., Tail cut

C.S., Cloacal segment of Wolffian duct

U., Ureter

G.E., Genital eminence

U.G., Urogenital sinus

H.G., Hind gut

U.M., Position of urogenital membrane

* Probable position of point where allantois joins cloaca.

All drawings represent 100 diameters enlargement except of Model F which is 50 diameters.

Links: plate 1 | 1 A | 1 B | plate 2 | plate 2C | plate 2D | plate 3 | plate 3E | plate 3F | Pohlman 1911

Reference

Pohlman AG. The development of the cloaca in human embryos. (1911) Amer. J Anat. 12: 1-26.


Cite this page: Hill, M.A. (2024, February 27) Embryology Pohlman1911 plate3E.jpg. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/File:Pohlman1911_plate3E.jpg

What Links Here?
© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G

File history

Click on a date/time to view the file as it appeared at that time.

Date/TimeThumbnailDimensionsUserComment
current15:55, 15 June 2016Thumbnail for version as of 15:55, 15 June 20161,988 × 1,895 (198 KB)Z8600021 (talk | contribs)==Plate 3E== {{Pohlman1911 figures}}

The following page uses this file:

Metadata