The vagina is an organ located between a woman's uterus and vulva that is responsible for producing sexual fluids during sexual intercourse. It also has a mucosal lining that secretes a lubricating fluid to help facilitate intercourse and keep it from becoming painful. This mucosa is made up of epithelial cells that secrete glycoproteins such as mucin, which act as natural antibiotics to help fight off any bacteria or viruses that may enter the body through this area. The amount of secretion varies depending on factors such as age, menstruation cycle, stress level, and hormones.
During ovulation, when a woman's ovaries release an egg into her fallopian tubes, they secrete more estrogen than usual. Estrogen stimulates the production of cervical mucus, a clear and slippery substance that helps sperm swim towards their target. If there are no sperm present in the vaginal canal, this secretion will become thicker, sticky, and white due to its composition of electrolytes like potassium and sodium chloride. After ovulation occurs, the levels of progesterone rise; this hormone causes the thickness of the mucus to decrease but increases its acidity level. This combination creates a hostile environment for sperm and prevents them from surviving long enough to fertilize the egg.
When women experience sexual arousal, blood flows to the genitals, causing increased lubrication and wetness. This process is called vasocongestion, which leads to increased permeability (allowing things to pass through) and changes in pH balance. These changes prepare the vagina for intercourse by providing adequate moisture while also making it less hospitable for pathogens. Additionally, during orgasm, muscles contract around the uterus, increasing pressure inside the pelvic cavity and expelling any remaining semen or vaginal fluids. The vagina can produce up to 100ml of fluid per minute!
In addition to protecting against infections, the vagina's mucous membrane plays an important role in reproduction by creating an ideal environment for sperm cells to enter the body and reach the egg. It does so by producing cervical mucus with proteins that promote motility - movement. Without these secretions, sperm would not be able to travel upward into the fallopian tubes where they can meet their target!