Hello students, there is a lot of misinformation about how reproductive systems work out there, so I'm here to set the record straight. Today's lesson is on the Female reproductive system, since this is the more complex system, and has the most misconceptions floating about.
Myth 1: period blood is "waste blood"
Truth: in Mammals offspring grow inside of a living female, and tap into her blood supply for nutrients. The baby does not pass blood back and forth with the mother, rather an organ called the placenta "roots" itself into local veins and arteries, and the waste and nutrients are diffused across the umbilical cord between the baby and the placenta.
In mammals with long pregnancies, this experience is extremely energy costive and many mammals have developed ways of terminating weak offspring that would likely be unable of surviving outside of the body, and be a waste of energy.
In humans, we have developed menstrual periods. Although time frames vary from person to person, the average time frame it takes for a healthy zygote (a fertilized egg) to "root" to a local artery after implantation is 3-4 days.
Generally, it takes 10 days for an egg to be released, (a process called ovulation) to be fertilized, and to implant. This is why most women have their period 14 days after ovulation.
If an egg has been fertilized, but the zygote is weak and has not rooted to a vein yet, the pregnancy will likely be a large waste of energy to the woman, without producing an offspring capable of survival outside of the womb.
During the first half of the menstrual cycle, the woman's body is building up thick uterine tissue to give the fertilized egg a place to implant. If no placental vein has rooted within 14 days of ovulation the women's body sends hormones to break up the thick uterine tissue, causing it to leave the body with any unfertilized eggs, or eggs that were fertilized but could not properly implant.
As the lining of the uterus is shed, some blood will escape with it. This is not waste blood. It is not full of toxins no matter what your local priest or anorexic vegan has told you. This is normal blood, entering the uterus as all organs need blood to survive. The blood escapes through the openings left by the shed lining.
I sure hope this lesson has been educational for you, I will be here to answer any additional follow up questions.
but that makes it waste by definition. heres a lesson in logic for you: