Bacterialvaginosis is a disease that's caused by the overgrowth of a type of bacteria that's called Gardnerella vaginalis, Gardnerella vaginalis. And as the name might suggest, this is the most common vaginal infection. Now I wanna put these really big quotes
around the term infection because the thing that's interesting about Gardnerella vaginalis is that it's a bacteriathat's naturally foundthe vagina. Now some may consider this to be a sexually transmitted infection, which is interestingbecause it doesn't cause
any problems until there'stoo much of it there. So when we look to the causes of bacterial vaginosis, they are all things that change the vaginal environment. That can include acts like douching, so douching, or rinsing of the vagina. The other is having newor multiple sex partners.
And finally, another known cause is the use of antibiotics. This could bethe case of somebody that has a throat infection or a pneumonia that's on antibiotics which will then attackthe bacteria that exists within the vagina andallow Gardnerella vaginalis to overgrow and cause bacterial vaginosis.
So we've touched a little bit on it here, but I wanna aw it out. So when we talk about the pathophysiology of a disease, we'retalking about the mechanism by which that disease occurs. Soorder to understandthe pathophysiology of bacterial vaginosis, we need to take a look at a sample of bacteria
that existsthe vagina. So I'll aw out someGardnerella vaginalis bacteria, and so I'll put this upour key. This is the symbol forGardnerella vaginalis. And I'll aw a few of them around here, but I also wanna show that there are a lot of other bacteriathat existthis sample. So if you really look at it here,
The Science of Plan B Emergency Contraception
Contraception, with a variety of methodsavailable many people are able to avoid unintended pregnancies. But what happenswhen things don't go quite as plannedé Thanks to modern science a second chanceis possible. So how does emergency contraception or quot;planbquot; worké And whatexactly is happening inside the female bodyé During the female menstrualcycle many hormones are released beginning a chain reaction. The pituitaryglandthe brain releases FSH which stimulates the growth of folliclesand a premature eggthe ovaries. These follicles then releaseestrogen
which helps prepare the uterus liningand triggers the brain to release leutinizing hormone or LH. LH thentriggers ovulationwhich the egg is released into the fallopian tubes where itwill spend around twelve to twentyfour hours waiting to be fertilized. If theegg isn't fertilizedthis time it begins to dissolve and is shed away withthe uterine lining during menstruation. Though this window of opportunity is briefit's increased by the fact that sperm can live for up to five days. So the keen sperm from days ago show up early to the show anxiously awaiting
ovulation. Birth control pills taken on a regularbasis modify these hormone levels. By increasing progestin levels the bodythinks it's already released an egg or already pregnant. It effectively decreases FSH and LH and the cycle halts. Butthe case of emergency contraception which is onlytaken if regular contraception methods fail, a few different mechanisms take place. The most important thing to understand
is that fertilization doesn't happenimmediately or even within hours after intercourse. Instead the sperm mustundergo a few biological changesthe fallopian tube first which takes time. This is why emergency contraception is still possible the morning after. It can actually work up to five daysafter intercourse. If taken during the first half of the menstrual cycle,emergency contraception works specifically to prevent ovulation. This way the egg is not released eventhough it may be ready and the available
sperm cannot fertilize it. In cases where it's too late to inhibit ovulation emergency contraception is thought toalso thicken cervical mucus trapping sperm. As well, it may directly inhibitfertilization between sperm and egg. al studies show that emergencycontraception prevents pregnancy before fertilization. No studies haveshown an effect from emergency contraception if fertilization hasalready occurred. It does not stop
implantation from happening nor does ithave any effect after implantation has occurred. In this way, its unable to cause an abortion. And while there are some minor side effects tothese ugs, such as nausea and headaches, scientific studies have demonstrated itssafetywomen of all ages and found that the benefits far outweigh any risks. Got of burning question you want answeredé Ask itthe comments or on facebook and twitter, and subscribe for more weekly science tutorials.