Term of the Day

Blood-Testes Barrier: This refers to the ability of the sustentacular (Sertoli) cells of the seminiferous tubules to prevent potentially toxic or harmful substances from entering or leaving the tubules. Many proteins, ions, hormones, and drugs are blocked from access to the developing spermatids. This works the other way, too. The barrier prevents the sperm in the tubules from diffusing into the bloodstream. This is a good thing, because sperm are immunogenic. That is, they are not recognized by cells of the immune system, so that if they entered the blood, they would be treated as foreign antigens and antibodies against them would be formed. This could lead to sterility.