‘The Vagina’ The vagina is a thin walled-tube, 8 to 10 cm long. It lies between the bladder & the rectum & extends from the cervix to the body exterior. The urethra is embedded in its anterior wall. Often called the birth canal, the vagina provides a passageway for delivery of an infant & for menstrual flow. Since it receives the penis (& semen) during sexual intercourse, it is the female organ of copulation. The highly distensible wall of the vagina …showed first 75 words of 1665 total…

…showed last 75 words of 1665 total…the vagina are incapable of penetrating a oocyte. They must first be capaciated (their membranes must become fragile so that the hydrolytic enzymes in their acrosomes can be released). The sperm that arrive first on the scene help break down the outer layer of the egg, so other sperm can penetrate it; only one sperm is allowed in, after that there is an electrical event called the ”fast block to polyspermy.” Then when the 2 pron