The kidneys of human embryos and fetuses aging from 5 to 40 weeks were investigated with a light microscope to study the development of glomerulus.,
The results were as follows;
1. The metanephros developed from metanephric blastema and ureteric bud.
The glomeruli of the stage I, 11, 111 on the criteria of Vernier and Birch-Andersen (1962) appeared in the embryo of 8 weeks and formation of new glomerulus ceased after 34 weeks.
2. The initial development of glomerulus appeared at subcapsular area of kidney and course of sequential development was metanephric tissue cells, metanephric tissue cap, cell mass, renal vesicles S-shaped body, and fusion with the terminal branch of the ampulla.
3. The capillaries appeared in the metanephric mesenchymal tissue of 7 weeks prior to the appearance of ;glomerulus. Capillaries, RBCs, and surrounding mesenchymal cells.were observed at the site of the invagination of the first cleft.
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