Mesonephric tubules are genital ridges that are next to the

mesonephros The mesonephros () is one of three excretory system, excretory organs that develop in vertebrates. It serves as the main excretory organ of aquatic vertebrates and as a temporary kidney in reptiles, birds, and mammals. The mesonephros is included ...

. In males, some of the mesonephric kidney tubules, instead of being used to filter blood like the rest, "grow" over to the developing

testes A testicle or testis ( testes) is the gonad in all male bilaterians, including humans, and is homologous to the ovary in females. Its primary functions are the production of sperm and the secretion of androgens, primarily testosterone. The ...

, penetrate them, and become connected to the

seminiferous tubules Seminiferous tubules are located within the testicles, and are the specific location of meiosis, and the subsequent creation of male gametes, namely spermatozoa. Structure The epithelium of the tubule consists of a type of sustentacular cells ...

of the testes. They also form the

paradidymis The term paradidymis (: paradidymides; organ of Giraldés) is applied to a small collection of convoluted tubules, situated in front of the lower part of the spermatic cord, above the head of the epididymis. These tubes are lined with columnar c ...

. The

sperm Sperm (: sperm or sperms) is the male reproductive Cell (biology), cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm ...

differentiate inside the seminiferous tubules, then swim down these tubes, then through these special mesonephric tubules, and go down inside

Wolffian duct The mesonephric duct, also known as the Wolffian duct, archinephric duct, Leydig's duct or nephric duct, is a paired organ that develops in the early stages of embryonic development in humans and other mammals. It is an important structure that p ...

, to the

coelom The coelom (or celom) is the main body cavity in many animals and is positioned inside the body to surround and contain the digestive tract and other organs. In some animals, it is lined with mesothelium. In other animals, such as molluscs, i ...

and finally to the organ the animal uses to transport sperm into females. In females, the structure gives rise to the paroöphoron.

References

External links

* * http://www.uoguelph.ca/zoology/devobio/210labs/kidney2.html Embryology of urogenital system {{Developmental-biology-stub