Bird, testis (LM, Low)

Structure List Adrenal Epididymis Spermatogonium Spermatocyte Interstitial cells High Magnification View

TESTES OF THE BIRD. Unlike mammals, the testes of birds are located within the abdominal cavity. They are surrounded by abdominal air sacks, but this does not change the temperature, which is the same as the surrounding tissues (104o F). The major portion of the testes is the seminiferous tubules. The cells lining the tubules divide and undergo maturation to form spermatozoa. The spermatozoa develop in clusters with their heads embedded in the cytoplasm of the sustentacular cells (Sertoli cells). The tails protrude into the lumen. Once mature, spermatozoa are released into the lumen of seminiferous tubules and pass into the efferent ductules and then to the epididymis. From there they are taken by the ductus deferens to the cloaca. Note that the cloaca is identical for both male and female.