histological epididymis and testis human cells under microscope.

histological epididymis testis human cells microscope anatomy testicles gynecology tail nucleus duct spermatogonia spermatids magnification scrotum semen sperm cell spermatozoid infertile fertile microscopic science gland tissue biology reproduction healthy structure medicine genetic penis cytoplasm organ male reproductive histology vitro birth control flagella infertility sex gametes fertilization test tube donation spermatozoa donor swimming