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).
Best Answer: Sperm are thought to retain fertilizing capability for up to 48 hours once they have entered the female genital tract, but it's possible their lifespan is even longer. Sperm production by the testicle takes about 90 days; the immature sperm are then deposited in a receptacle called the epididymis.est Answer: Sperm are thought to retain fertilizing capability for up to 48 hours once they have entered the female genital tract, but it's possible their lifespan is even longer. Sperm production by the testicle takes about 90 days; the immature sperm are then deposited in a receptacle called the epididymis.