UNSW Embryology

Development of the Kidney and Reproduction Systems - Selected Stage 22

© Dr Mark Hill (2009)

Acknowledgements

Introduction

The links below are to selected images from the Carnegie stage 22 embryo. The first image in each set is a low power image of the entire embryo cross-section, followed by the selected (red box) region showing specific features that relate to urogenital development. Beneath these links are links to related histology images.

Mesonephric duct (ductus deferens) and Paramesonephric duct (degenerating) in relation to the mesonephric kidney (degenerating) and testes (developing). Inset (lower left) shows whole embryo section.

Kidney (stage 22)

F4,F5: Kidneys. Ureters. In F5, note the great volume of renal interstitium and the younger nephrons at the periphery of the kidney and the older nephrons closer to the hilus. Renal capsule, corpuscle, tubules. Note extensions of the ureteric tree - the collecting tubule system, derived from the ureteric bud. The strands across the lumen of the large, calyx-like structure are degenerating partitions. Similarly, the junction of the collecting tubule and nephron tubule at top-right of screen. Note comma-like shapes of young nephrons.

F6: Renal corpuscles with glomeruli inside Bowman's space. Narrow renal tubules and collecting ducts. Interstitium. Proximal and distal tubules defined by cell height. Macula densa region developing at the most central glomerulus.

G1: Aorta. Inferior vena cava. Ureters with spiral smooth muscle (cf. thick muscularis of adult ureter).

G2: Mesonephros with tubules and remnants of glomeruli. Mesonephric duct. paramesonephric duct.

G3: Testis. Degenerating mesonephric glomeruli and tubules (precursors of outflow ducts of testis).

G6,G7: Bladder with ureters entering laterally (ureters also descending retroperitoneally beside rectum). Fusion of paramesonephric ducts in midline, with mesonephric ducts laterally.

Genital (stage 22)

F7,G2: Paramesonephric duct (regressing in male). Mesonephric duct. Mesonephric tubules. Mesorchium. Urogenital mesentery.

G3: Testis with radiating cell sheets becoming cords (defines the gonad as the testis).

Mesonephric tubules (ductuli efferentes). Mesonephric glomeruli. Mesonephric duct and, more laterally the thickened coelomic epithelium of the paramesonephric groove. Narrow mesorchium and pale external layer of tunica albuginea. Definitive kidney.

G4: Cell plates of testis (becoming cords) containing the germ cells. interstitial cells. large cells with dark nuclei and distinct halo of unstained cytoplasm are the germ cells (spermatogonia).

G5-G7: Fusion of paramesonephric ducts (forming prostatis utriculus in male; uterus and part of vagina in female). Mesonephric ducts. Ureters. Bladder. Umbilical arteries.

UNSW Histology Slides

The following slides are from the UNSW, Department of Anatomy, Histology Slide Set 2003. Slides are numbered according to the Histology Set number. The tissues listed relate to this developing system. Note that most slides are from mature tissues (unless otherwise indicated, see also all slides).

UNSW Dept of Anatomy- Histology Page

UNSW Histology Slides
Slide	Tissue	Animal	Stain
84 85 92A 94 94A 95 95A 86 87A 93 92 92A 93 91 90 90A 89 91A 86 86A 87 87A 83 83A 84 85 93 94 94A 95 95A 96 97 97A 88	Bladder, urinary (relaxed) Bladder, urinary (distended/relaxed) Ovary, corpus luteum Cervix (LS) Cervix (LS) Endometrium (secretory) Endometrium (late proliferative) Testis (LS) Testis, Epididymis Uterine tube (oviduct) Ovary Ovary, corpus luteum Uterine tube (oviduct) Penis, neonatal (TS) Prostate Prostate Seminal vesicle Spermatozoa Testis (LS) Testis Testis Testis, Epididymis Ureter Ureter Bladder, urinary (relaxed) Bladder, urinary (distended/relaxed) Uterine tube (oviduct) Cervix (LS) Cervix (LS) Endometrium (secretory) Endometrium (late proliferative) Uterus, Placenta Vagina Vagina (lateral wall smear) Vas deferens	human monkey human human human human human cat monkey human cat (kitten) human human human chimp dog ox human cat cat human monkey human chimp human monkey human human human human human human human human human	Masson's Trichrome H & E H & E H & E PAS, Haematoxylin H & E H & E Masson's Trichrome H & E H & E H & E H & E H & E Masson's Trichrome H & E H & Van Gieson Heidenhain's Azan & Masson's Trichrome Iron Haematoxylin Masson's Trichrome Gomori's Trichrome H & E H & E H & E H & Van Gieson Masson's Trichrome H & E H & E H & E PAS, Haematoxylin H & E H & E H & E H & E Shorr (modified) H & E

Glossary of Terms

A |B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W |X | Y | Z

Quick Links

Urogenital Pages:

Abnormalities | References | OMIM | Questions | Medline | Pig (stage13/14) | Human (Stage22) | Selected Human highpower
Text only page | WWW Links

Development Notes ----------------- Menstrual Cycle Week 1 Week 2 Week 3 Week 4 Placenta Serial Images Genes/DNA Molecular Dev Abnormal Dev Postnatal Dev Notes Index

System Notes ----------------- Heart/Cardiovascular Respiratory Coelomic cavity Gastrointestinal Tract Head and Neck Neural Neural Crest Eye Ear Nose Endocrine Urogenital Musculoskeletal Integumentary

Movies ----------------- Embryo Growth Ultrasound Week 1 Week 2 Week 3 Week 4 Stage 13/14 Stage 22 Neural Head and Neck Heart Vasculature Gastrointestinal Urogenital Other Embryos Larsen Internet

Other Embryos ----------------- Chicken Fly Frog Mouse Rabbit Rat Worm Zebrafish Guinea Pig

UNSW Embryology ISBN: 978 0 7334 2609 4

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