The Reproductive System
Reproduction is accomplished by the union of male sperm and the female ovum. In coitus, the male organ ejaculates more than 250 million sperm into the vagina, from which some make their way to the uterus. Ovulation, the release of an egg into the uterus, occurs approximately every 28 days; during the same period the uterus is prepared for the implantation of a fertilized ovum by the action of estrogens. If a male cell fails to unite with a female cell, other hormones cause the uterine wall to slough off during menstruation. From puberty to menopause, the process of ovulation, and preparation, and menstruation is repeated monthly except for periods of pregnancy.
- reproduction [ˌri:prəˈdʌkʃən] n.繁殖, 生殖
- accomplish [əˈkɔmpliʃ] v.完成
- sperm [spə:m] n.精子
- ovum [ˈəuvəm] n.卵子
- coitus [ˈkəuitəs] n.性交
- ejaculate [iˈdʒækjuleit] v. 射精
- vagina [vəˈdʒainə] n.阴道
- uterus [ˈju:tərəs] n.子宫
- ovulation [ˌɔvjuˈleiʃən] n.排卵
- egg [eɡ] n.卵
- implantation [ˌimplɑ:nˈteiʃən] n. 胚胎植入
- fertilized [ˈfə:tilaizid] adj. 已受精的
- estrogen [ˈestrədʒən] n.雌激素
- slough off [slau - ɔf] v. 脱落
- menstruation [ˌmenstruˈeiʃən] n. 月经期间
- puberty [ˈpju:bəti] n.青春期
- menopause [ˈmenəpɔ:z] n.经绝期
- pregnancy [ˈpreɡnənsi] n.怀孕
