turner syndrome is a condition in which there is a lack of one or both testes.
a condition in which there is a lack of one or both testes?
turner syndrome
bullet::::- the testes develop relatively normally initially, but are slightly smaller than normal and possess various defects. by 20 weeks, the weights of the testes, epididymis, and vas deferens are significantly decreased relative to those of normal mice. however, there is a severe testicular phenotype with age, such that the testes are completely atrophied by 150 days of age. also, the testes show leydig cell hyperplasia, which is due to the increased levels of lh and intratesticular testosterone. further, there is a greater incidence of cryptorchidism (undescended/retracted testes).
estrogen insensitivity syndrome
the basal condition for mammals is to have internal testes. the testes of the non-boreotherian mammals, such as the monotremes, armadillos, sloths, and elephants, remain within the abdomen. there are also some marsupials with external testes and boreoeutherian mammals with internal testes, such as the rhinoceros. cetaceans such as whales and dolphins also have internal testes. as external testes would increase drag in the water they have internal testes which are kept cool by special circulatory systems that cool the arterial blood going to the testes by placing the arteries near veins bringing cooled venous blood from the skin.
testicle