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Langman 14-2

Vest>giai pronephric system

Mesonephric excretor units

Mesonephric

dud

g Ureteric bud

Three kidney systems are formed, pronephros, mesonephros, &

metanephros. 1** is nonfunctional, 2^nd may functional in fetus. 3^rd becomes permanent kidney.

■ i. ■    . _r .    - Viteltme

Lateral end of nephnc duet

Segmented mtermediate mesoderm (pronephric system)

Unsegmented mtermediate mesoderm (mesonephric system)

BtoAca

Allantots

Mesonephnc duet

Unsegmented mesoderm (meianephric system)

tubuies grow caudaliy to form a iongitudinai collecting duet - the

mesonephric (wolffian) duet. It empties into the eioaea (urogenital sinus).

Mesonephros buiges into coelomic cavity forming urogenital ridge or fold.

Observe the ureteric bud off the mesonephric duet entering the unsegmented mesoderm that will form metanephros.