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).
A male (â) organism is the physiological sex that produces sperm. Each spermatozoon can fuse with a larger female gamete, or ovum, in the process of fertilization.A male cannot reproduce sexually without access to at least one ovum from a female, but some organisms can reproduce both sexually and asexually. male (â) organism is the physiological sex that produces sperm. Each spermatozoon can fuse with a larger female gamete, or ovum, in the process of fertilization.