Talk:Renal System - Carnegie Stage 13

Shown below is a set of cross-section slice extracts of the lefthand urogenital system in rostro-caudal sequence. Clicking on each image will open full serial section, below this panel is a description and link to individual images.

[../wwwpig/pigg/G6L.htm G6,G7]: Cranial and caudal extent of mesonephros (the mesonephros is never so well-developed in equivalent human embryos). Youngest mesonephric tubules at caudal end. Mesonephric duct in G7.

Stage 13/14 Embryo

[../wwwpig/pigd/D6L.htm D6]: Mesonephric tubule at medial wall of inferior cardinal vein. Broad urogenital ridge. Paired dorsal aortae.

[../wwwpig/pigd/D7L.htm D7-E1]: Glomeruli. In E1, note form of urogenital (UG) ridge and urogenital "mesentery". In the UG ridge, identify the subcardinal vein and the mesonephric (Wolffian) duct. Dorsal aortae fuse.

[../wwwpig/pige/E4L.htm E4]: Afferent glomerular arteriole from dorsal aorta. In UG ridge, note medial location of glomeruli and lateral location of convoluted tubules and mesonephric duct.

[../wwwpig/pige/E5L.htm E5-F4]: Note further lateral displacement of mesonephric duct in UG ridge. Note medial thickening of coelomic epithelium of the UG ridge (gonad precursor - prominent in F2).

[../wwwpig/pigf/F7L.htm F7]: Afferent arteriole. Mesonephric duct.

[../wwwpig/pigg/G1L.htm G1-G4]: Lumbar region of mesonephros. Mesonephric ducts. Dorsal aorta. Intraembryonic coelom. In G3, note many tubules are cut in LS.

[../wwwpig/pigd/D5L.htm D5-G4]: Section passes dorsally to the mesonephros. Return to G4 and then follow the caudal route of the mesonephric duct into the sacral region.

[../wwwpig/pigg/G3L.htm G3-Fl]: Sacral mesonephric ducts, located laterally in the UG ridge. Mesonephric structures smaller in more caudal regions. Division of dorsal aorta. In Fl, note rectum, urogenital sinus, allantois and intra-embryonic coelom.

[../wwwpig/pige/E7L.htm E7]: Most caudal extent of mesonephros, with mesonephric ducts (lateral). Rectum and urogenital sinus with urorectal septum in between. Umbilical artery (L side). note shape of Intraembryonic coelom on L. Site of caudal attachment of connecting stalk to body wall.

[../wwwpig/pige/E6L.htm E6]: Lateral branch of dorsal aorta forming common iliac artery. Umbilical artery. Lower limb bud (damaged on R side). Junction of rectum and urogenital sinus. Urorectal septum continues laterally as two crests. Detached connecting stalk.

[../wwwpig/pige/E5L.htm E5]: Near caudal limit of I-E coleom. Umbilical artery sweeps lateral to the coelom, which in turn, lies lateral to the mesonephric duct.

[../wwwpig/pige/E4L.htm E4]: Mesonephric duct. Dark mass of mesenchyme (medial) is the metanephrogenic cap = precursor of the definitive kidney. Note lateral extensions of urogenital sinus - the terminal

mesonephric ducts. The two crests between the rectum and each mesonephric duct are still the lateral extensions of the urorectal septum.

[E3,E2]: Mesonephric ducts joining to urogenital sinus. Urorectal septum. Metanephrogenic caps. Cloacal membrane.

Stage 13/14 Embryo - Genital System

[E1-F4]: Urogenital ridge with broad attachment to dorsal abdominal wall. Medial thickening of coelomic epithelium of UG ridge is site of gonad development (prominent in F2). Mesonephric duct.

[F4-G4]: Follow the caudal course of the mesonephric ducts.

[G2-F2]: Follow further the caudal course of the mesonephric ducts up into the sacral region of the embryo. In F2 note colon and mesocolon attaching to dorsal body wall; also allantois, umbilical artery, umbilical vein. (Limb etc. missing on one side - artefact). F1: Umbilical vessels. Allantois joining to urogenital sinus. Mesonephric ducts. note coelom joining of ventral and dorsal body walls with rectum in between, and urogenital sinus in ventral body wall. Urorectal (UR) septum in tissue between hindgut and UG sinus. Site of attachment of umbilical cord (connecting stalk component) to the ventral body wall. Note shape of coelom.

[E6]: Junction of hindgut and urogenital sinus. UR septum continues laterally and caudally ("upwards") as two crests or flanges. Small coelom. Umbilical artery near junction to iliac artery, aorta. Mesonephric duct.

[E5]: Umbilical artery arcs to side of the coelom. Mesonephric duct. E4: Increase in caliber of mesonephric duct at site where ureteric bud arises. Definitive kidney to medial side. Lateral extensions of UF sinus.

[E3-E2]: Mesonephric ducts joining urogenital sinus. Hindgut. Cloacal membrane.