Vitiligo Definition and Overview. Vitiligo is an autoimmune skin disease in which there is a progressive destruction of the skinâs pigment-producing cells (melanocytes), resulting in areas of otherwise normal white skin devoid of melanin pigment. It is not unusual for hairs growing in areas of vitiligo to lose their normal color.
Sperm Cycle. Old sperm cells die off and new cells are created at a rate of about one percent each day. This means the entire sperm cycle requires approximately 100 days. The final 75 days represent a period of maturation for the sperm cell. This final step of sperm maturation, called spermiogenesis, puts the fuel into the tank and completes the development of the sperm cell (spermatozoon).
The male reproductive organs include the testes, the epididymis, the vas deferens, seminal vesicles, prostate, bulbourethral glands, scrotum and penis.Nearby structures are the bladder and rectum. Sperm are produced in the testes and move into the epididymis where they mature over a period of 10 to 14 days.Sperm are stored here and in the vas deferens where they can remain viable for several months.earby structures are the bladder and rectum. Sperm are produced in the testes and move into the epididymis where they mature over a period of 10 to 14 days. Sperm are stored here and in the vas deferens where they can remain viable for several months.