Back to Mesoderm…!
Development After lateral folding… of under coelomic epithelium Urogenital Systems Lengthwise column Urinary system : ANHB 2212 – 2008 Nephric tubules Avinash Bharadwaj Open in the coelomic cavity, later…
Draining duct
The Kidney Story… Pronephros
8 to 10 “segments” – cervical Developmental and evolutionary Cell groups… Successive parts of intermediate mesoderm craniocaudal sequence
Begins high up Disappear completely Three sets of “kidneys” Do not function as kidneys (only some species of fishes) First, middle and ‘other’ (final).
Pronephros, mesonephros and metanephros
Mesonephros Step-by-step …
Thoracolumbar region Sectional view… Tubules
Duct : mesonephric duct (Wolffian) Aorta Mesonephric duct Caudal end :
Cloaca Æ urogenital part nd 2 month events Functional for a short period Paramesonephric duct
1 Mesonephros disappears Metanephros
Tubules regress Caudal end of nephrogenic cord Duct persists… …put to some use! Duct : diverticulum from mesonephric duct Æ Ureteric bud
Migrates cranially
Metanephros Collecting System Pelvis Major calyces Minor calyces
Major calyces Metanephric cap Pelvis Æ Urine-forming part Pelvis Major and minor calyces Ureteric bud Major calyces Collecting ducts Æ Collecting system Metanephric cap Æ tubules
The Nephron The Nephron…
Cell clusters around blind ends Glomerulus of tubules Parts of the tubule PCT Hollow DCT Thin part Æ Bowman’s capsule Proximal convoluted
Rest Æ tubule Loop of Henle Loop Distal convoluted
Communication essential !
2 Ascent of Kidney Reproductive Organs
Blood vessels : Gametogenic cells… successive sources Gonadal ridge
Fused kidneys : Mesonephric and Arrested by IMA x paramesonephric ducts
Gonads descend
Common plan… M Differentiation P
Male System Female System
“Gubernaculum” M Paramesonephric duct
Mesonephric duct Fusion : caudal part P Æ Uterus
Cranial : Tube
Uterine abnormalities.
Female System Final Picture Uterine tube Descent stops in the Müllerian duct Ligament pelvis * of ovary* Gubernaculum Æ Fibrous cords Ovary Ligaments : Round Uterus : ligament Fused Müllerian Of ovary of uterus ducts Round ligament of uterus Vagina
3 Implications of Descent
Blood supply
Veins
Nerves
Lymphatics
Inguinal canal and its contents
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