Ejaculate and cervical mucus. Animation showing ejaculate (seminal fluid or semen) forming a puddle at the base of the cervix (the neck and entrance to the uterus). The ejaculate has pooled here after passing down the vaginal canal after ejaculation in the vagina. The animation shows mucus emerging from the cervix. Cervical mucus, depending on its composition and the stage of the menstrual cycle, can aid or impede the sperm in the ejaculate from passing upwards into the uterus and onwards to the Fallopian tubes. Those sperm that encounter an ovum (egg cell, female sex cell) will attempt to fertilise it as part of the process of sexual reproduction.