Sexual Intercourse

• Penis fills with blood and becomes erect
• Vagina walls secrete a lubricant.
• Rubbing of the glans (end of penis) against the vagina wall sets of a reflex action, causes sperm to be released from the testes, and is transported by peristalsis along sperm ducts and urethra, where seminal fluid is added to make semen.
• The exit of semen from the penis is called ejaculation.
• Sperm then swim through the cervix and oviducts to the first third of the oviduct (from the ovary) where one combines with the egg.