 Hey everybody, Dr. O. This video we're going to talk about the gonads and talk about the sex hormones. So it all begins so puberty when a boy starts developing a man and a girl starts developing a woman is going to be triggered by gonadotropin releasing hormone, which is one of the regulatory hormones from the hypothalamus. So it actually, as you can see here on the right hand side, the gonadotropin releasing hormone starts to increase around the age of eight, but you see that as estrogen and testosterone are produced, there's massive amounts of negative feedback that keep a child at the age of eight, in most cases anyways, from developing too much estrogen and too much testosterone. So the system is basically in check. But then once a kid reaches puberty that you start to see less sensitivity there and the numbers will start to climb up and then puberty will kick in. So that's where it all begins with gonadotropin releasing hormone. Gonadotropin releasing hormone will tell the anterior pituitary gland to produce and release the gonadotropins, which will be follicle stimulating hormone and luteinizing hormone. So the two, the two are going to have an impact on both men and women. Let's go ahead and just read number three here, luteinizing hormone and follicle stimulating hormone trigger testosterone production in the testes and estrogen production in the ovaries. So it's a little more nuanced than that. So let's kind of walk through this. So follicle stimulating hormone in the female is going to lead to the development of the follicle. And the follicle is going to be where the egg is. So follicle stimulating hormone is going to lead to the production of the egg, the oocyte. But the follicle will also then release estrogen. So that's why follicle stimulating hormone leads to estrogen production in females. In males, follicle stimulating hormone is going to lead to spermatogenesis or the production and maturation of sperm. So that's follicle stimulating hormone. Luteinizing hormone in females is going to lead to the spike in luteinizing hormone is going to lead to ovulation. And it's also going to lead to the production of the progesterones, which are very important for successful pregnancy and maintaining pregnancy. So luteinizing hormones role in females is primarily to increase progesterone levels. And I remember that in females is that F comes before L, follicle stimulating hormone comes before luteinizing hormone, E estrogen comes before P progesterone. In males, luteinizing hormone is going to tell the testicles to produce more testosterone. So just think follicle stimulating hormone, think the gametes, the sex cells are being produced. Luteinizing hormone think hormones primarily. All right, let's go ahead and look at the effects. This is what I wanted to talk about really in this video because we've kind of covered that part already before. But we talk about testosterone leading to male secondary sexual characteristics and estrogen leading to female secondary sexual characteristics. First of all, why are they secondary? Well, the primary sexual characteristics are a male would have a penis. And really the testicles would be the key, the gonads. And in estrogen, the primary sexual characteristic would be the ovaries. So everyone has gonads. It's just whether or not they would be considered the male or female gonads. But the secondary sexual characteristics, let's go ahead and read through the list. So the male secondary sexual characteristics, penis and scrotum growth, facial hair is going to grow in a male pattern. The larynx is going to elongate, which makes the vocal cords longer and that's going to lower the voice, a broadening of the shoulders, body armpit and pubic hair growth, and musculature increase, so increase in bone density, increase in muscle mass. Female secondary sexual characteristics are going to be the breast will start to develop and mature, the hips will broaden, so the female pelvis is broader to make way for the birth canal for the baby. And then pubic hair growth, so you're going to see different secondary sexual characteristics. Now, of course, we've got a spectrum here and there's different growth patterns, so some men are going to have a lot more body hair than other men and the same thing with women, et cetera. But that's going to be the secondary sexual characteristics that develop because of these sex hormones. All right, a couple more to cover here. So we talked about testosterone being that primary male hormone. The other two that we haven't talked about, and we also talked about estrogen quite a bit, but remember progesterone plays a big role in the menstrual cycle. We'll cover that when we talk about the femur reproductive system. It's very important to maintain the pregnancy, but what I want to talk about here is the placenta. So the placenta becomes this temporary endocrine organ and it produces lots of different things, but the main one we care about is human, chorionic and atotropin. So we won't go through all this, but after ovulation, you do see this temporary increase in progesterone, and if it doesn't stay elevated, then there won't be a pregnancy. And that's why the placenta's role is to keep progesterone levels elevated. The other important function of human, chorionic and atotropin is that it does play a role in suppressing mom's immune function. So if we think about it being pregnant is an immunosuppressive disorder. Reason that's important is because the baby's only half you. So if your immune system is firing on all eight cylinders, then it will recognize the baby is abnormal. So your immune system is suppressed while you're pregnant. This is why lots of women that have autoimmune diseases see an improvement in their symptoms while they're pregnant. So the placenta produces this important hormone, human, chorionic and atotropin. We'll talk about the other things that the placenta does when we talk about the female reproductive system, but it does. It produces the hormone relaxin, which allows for a relaxation of the soft tissue so the baby can make its way out of the birth canal. What is it? Human placental lactogen, which plays a big role in milk production, but that's beyond the scope of this early introductory chapter. So, all right, so these are the hormones involved in the male and female reproductive systems. I hope this helps. Have a wonderful day. Be blessed.