MATURATION OF THE BLADDER After cloacal septation is complete, the primitive urogenital sinus contains three major parts. The most caudal part is known as the definitive urogenital sinus, and it…
FATE OF THE MESONEPHRIC DUCTS By the end of the exstrophy process, the mesonephric ducts terminate in the bladder medial and inferior to the future ureteric orifices. Although it was…
The metanephroi begin to produce urine at 9 weeks of gestation, even as active nephrogenesis is ongoing. Such urination becomes essential for maintaining a normal volume of amniotic fluid. The…
METANEPHROS The paired metanephroi are the precursors of the definitive adult kidneys. They begin to form around the twenty-eighth day of gestation, shortly after the mesonephric ducts have fused with…
OUTER AND INNER MEDULLARY COLLECTING DUCT The outer medullary collecting duct (OMCD) consists of principal cells and a smaller population of type A intercalated cells. Both appear taller and less…
Unlike in the ureter, the lamina propria occasionally contains a muscularis mucosae, which appears discontinuous and contains a haphazard arrangement of wispy, thin bundles of smooth muscle cells. In some…
DISTAL CONVOLUTED TUBULE At some distance after the macula densa, there is an abrupt transition from the low cuboidal cells of the TAL to the taller cuboidal cells of the…
The extraglomerular mesangial cells are continuous with and resemble normal mesangial cells. They are linked to the granular cells via gap junctions, and they share a basement membrane and interstitium…
PROXIMAL TUBULE The proximal tubule receives urine from Bowman’s space. It plays a major role in the transport of material from the urine back into the blood (reabsorption) and vice…
