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.
Development of the embryo begins at Stage 1 when a sperm fertilizes an oocyte and together they form a zygote.. [England, Marjorie A. Life Before Birth. 2nd ed. England: Mosby-Wolfe, 1996, p.31] Human development begins after the union of male and female gametes or germ cells during a process known as fertilization (conception). Fertilization is a sequence of events that begins with the contact of a sperm (spermatozoon) with a secondary oocyte (ovum) and ends with the fusion of their pronuclei (the haploid nuclei of the sperm and ovum) and the mingling of their chromosomes to form a new cell.