How is sperm loss caused?

Azoospermia generally has two reasons, one is primary, the other is secondary, that is, divided into congenital azoospermia and acquired azoospermia. Congenital azoospermia is mainly due to testicular and no sperm production, if the testis is like a factory and does not produce sperm, so in the whole testicular puncture and ejaculation process are seminal fluid or prostatic fluid, and no sperm, so called primary azoospermia. On the other hand, it belongs to secondary azoospermia, that is, due to vas deferens obstruction and stenosis after ligation, the sperm produced in the testicles cannot enter the seminal vesicles through the vas deferens, so when the seminal vesicles contract, they pass through the ejaculatory duct, prostate gland, urethra and are discharged from the body. No sperm is found during ejaculation, which indicates that sperm is blocked during the journey. Therefore, there is no smooth ejection, which is called secondary azoospermia, that is, acquired.