 Well, next topic, that is the human male reproductive system, that is, the human male reproductive system. Well, the main function of the male reproductive system is to produce sperm and male sex hormone for fertilization of the ovum. So, these are the two main, you can say, the functions of the reproductive system. That is, sperm production and certain hormone production. Because of these hormones, you might have observed, as we call it as adolescence, that is, when a person becomes able to reproduce. Now, internally, when a person starts producing the sex hormone, which we call the testosterone, and because of this testosterone, when it comes into the blood, then secondary sex characters develop. Secretary sex characters means that the hoarseness, that sharpness ends in the voice, then changes occur in the throat, and then the body hairs develop, then beard, moustache, and that is undergarments that come here, pubic hair, they start developing. So, these are secondary sexual characters. So, this is all under the control of the testosterone. Now, the male reproductive system, now we will talk about the system, what are its different structures. So, it can be divided into three categories. The first category consists of organs, which are located out to the body. Or the organs which are out to the body, they are the testes, or, there is a present intramitant organ, which we call the penis. We have seen that the testes are oval shaped structures, which are present in the out-pocketing of the skin, which we call the scrotum. In newborn male baby, those scrotals sex, they are empty. But later on, in a few days, or at the time of the birth of the child, these testes, they descend down from inside. Or that becomes then complete the structure, which is the reproductive organs. So, these are produced in the testes, which are housed in the temperature-regulating pocket, the scrotum. Now, what is it called as a temperature-regulating pocket? It is a fact, Radha. It is a fact that the spermatogenesis, the sperm formation, is not at the body temperature. In the suitable temperature, there is about 34 or 35 degrees Celsius. Because our body temperature is 37. So, at a temperature of 3 to 4 degrees less, there is spermatogenesis. There is spermatogenesis. Okay, these are the testes. They are lodged in the out-pocketing of the skin, the scrotum, which may move upward to the body during winter or during that is summer. They tend to move away from the body to maintain the temperature, to maintain so that the spermatogenesis may continue. Then the immature sperm that travels through the epidermis. Now, here, in this diagram, we are seeing that this part is whole, the testes. And here, and this is the epidermis. And this is the capped epidermis. This is the cauda epidermis. And from here, the sperm ducts come out. So, the sperm formation is in this region. And from there, all the maturity of the sperms that occurs in the epidermis. And the sperms mature, then they start moving. And this is the next route that we will talk about. So, the immature sperms travel in the epidermis for development and storage. The testes also produce the male sex hormone, which we call the testosterone. Well, the secondary category, that is, are the structures located around the pelvis. That is lower abdomen, you can say. And in the lower abdomen of the male, they are divided into secondary categories. Now, these structures include fluid-producing glands, which we call bulborithral glands. In addition, seminal vesicles, then prostrate glands, or ductus deferens, which we also call the sperm duct. So, from here, these are the testes, which are present in the scrotal region, that moves inside, that is, lower abdomen. And from there, this is the epidermis. And this is the testes. And after that, this is the puliduct, the sperm duct. This sperm duct comes back in the lower body of the body. That is, it comes back with the uterus. And then it meets the seminal vesicles. And these are the glands. Here, there is the prostrate gland, just means that we meet together to form a single duct, then the bulborithral gland, this is a very small gland. And after that, it comes out through the penis. These are the secondary characters. These are secondary categories. In the secondary category, there are more ducts, which are within the body. And then, these are the urethra, which are coming from the kidneys. So, after that, the third category. The third category are those used for copulation and deposition of semen in vagina. That is the penis and the urethra. This part, this part, and this part. That is out of the body. Whereas the rest, these glands, the glands and the ducts, they are within the body. They are not visible. So, this is all about the male human reproductive system. So, as we mentioned earlier, it can be divided into three categories, three main positions, the testis, in which there is sperm production and then hormone production. We will look at this in detail when we look at its histology. And then there is the secondary category, which is within the body, which is in the pelvis region. And then there is the third category, which is the intromatant organ, which is the penis and along with the urethra. So, this urethra is a common passageway for the removal of the semen. What is semen? It is the secretions of these glands which we discussed earlier. Along with the sperms, these mixtures are so-called semi-solid. It is a thick mixture. That is what we call the semen. This is also given as a reproductive fluid. This is a reproductive fluid. So, this reproductive fluid is then introduced into the female reproductive system through the intromatant organ. So, this is all about the male reproductive system.