Related to Precordial pain: costochondritis, Pulsus paradoxus, retrosternal pain. unpleasant or hurtful sensation resulting from stimulation of nerve endings. The stimulus is carried by nerve fibers to the spinal cord and then to the brain, where the nerve impulse is interpreted as pain.
Full transcript. The sperm race begins Ejaculation The race resumes A man's penis releases around 20 million sperm into the woman's vagina, where they then begin their journey.Around 2,000 sperm then travel up to the top of the vagina and through the cervix.aiting for the egg When the sperm are awakened they travel to egg and the race resumes. Time to be born The mother's Muscles contract to push the baby out. The amnion sack breaks ('water' breaks). The head moves into the entrance of the vagina.
While women are born with all of the eggs they'll ever need, men aren't born with ready-made sperm. They have to be produced on a regular basis, and from start to finish it takes 64 to 72 days for new sperm cells to develop. The average sperm lives only a few weeks in a man's body, and about 250 million are released with each ejaculation.