 In this practical, we will learn about the reproductive system of vertebrates. First of all, we will see the vertebrates consist of testis. And in this vertebrates, excretive system and reproductive system both combine and form the urinogenital system. In some vertebrates, for example, lizard and snakes and chicken. If we talk about the reproductive system in this, the most important part is the testis. And in its testis, there are semi-ferrous tubules that are present in the reproductive system of invertebrates in many numbers. And in this, the structure of the kidneys and its tubes are completely separate. And the reproductive organs, the testis and the tubes are completely separate. And if we talk about the reproductive system, the chicken's reproductive system, then in a single time, chicken 3 to 5 million of sperms are released. And along with the testis, androgyne glands are also present, which not only help in sperm formation, but also help in determining the secondary sexual characteristics of the chicken. Now, what are those characteristics? For example, the formation of com, which is present on the head region of the hen. Apart from this, the size of the testis and the number of the sperm is decided in androgyne glands. If we compare it, in invertebrates, there are accessory glands, and in the reproductive glands, there is an advanced version of it, which is called androgyne glands. If we look at the structure of it, what is present? First of all, the male chicken is present on both the sides of the testis, and both the testis are functional. That means both the sperm cells are producing at a time. And in this, there are a lot of tubules, like in invertebrates, which are called salmonepharynx tubules. And the tubules of salmonepharynx tubules have sperm formation. And those sperms form from there, and go to another small tube, which is called apididmus. Apididmus is a long tube, which is called vas deferens. And here, the vas deferens, the testis are present in front of the kidneys, but it is a separate system, reproductive system and excretive system. Here, you have vas deferens, where the sperms move, and they come into a globule-like structure in the chicken, which is called papilla. And papilla is open in the clioca, and clioca is open in the vent. So, the sperms first come into the papilla, and they go through the vent through the clioca, they are removed, and they go into female chicken. If we look here, which parts are present in female chicken, then the reproductive system of female chicken is a little complex as compared to male chicken, because there are not only eggs in it, but external structures are also developed. If we look here, the chicken has a single left ovary, which is functional, whereas in male chicken, both the testis, both the sides of the vertebral column are functional. The ovaries lead in the oviduct, and the ovaries lead in the oviduct. Now, the oviduct is a duct that is accepted for receiving of eggs. As soon as the eggs, which are called follicles, which are mature follicles, are released from the ovaries, then it goes into the oviduct. Now, in female chicken, there are different parts of the oviduct in hen, and each part has its own separate function. Here, we can see that the first infundibulum is the region where female and reproductive cells are to be fissioned. After that, you have the second part of the oviduct, where there is a magnum, when the fission is done, and a zygote is formed, and it will be present in the yolk. In the yolk, there are other structures in the egg, which make different parts of the oviduct. Here, what the magnum will do? It will make an albumin, which is the whitish part of the egg. After that, it goes into the isthmus, and in the isthmus, the outer and inner shell membranes of the egg are formed. After that, the white calcium carbonate shell, which we can see, is formed in the egg. In the uterus's shell glands, there are many shell glands present here. Apart from that, there is an external structure, outside the shell, which is called cuticle, which is for protection. The pores of the egg that are present in the egg are sealed, so that any bacteria or soil particles do not go into the egg, and the egg does not get damaged. When the egg is formed, it comes into the vagina, and if there is any cuticle in the vagina, which is not formed in the uterus, then it is formed in the vagina, and after the vagina, the egg is taken out of a fully-dwelled form, through the clioca. The egg in the hen, which is also used as a food source, is present in the fertilized form. This is all about the excretory structure of vertebrates. Similarly, in humans and reptiles, the main excretory structures are here. If we talk about females, there are ovaries in them, and there are oviducts, uterus and vagina. If we talk about males, there are testes, there is vas deferens, and after that there is penis, through which sperm is transferred. The overall structure, general structure of any system is similar to all the classes of vertebrates. So, students, in this practical study, we studied the reproductive structure of vertebrates, and in this, we studied the structure of chicken, male chicken and female chicken. The reproductive structure of male chicken is to make just sperm cells, and transfer them into the female body. The female chicken is the work of follicles or mature eggs, which we call as fusions in the oviduct, and the different parts of the eggs, such as shell, outer membrane, inner membrane, and cuticle, are all in the oviduct, and they come out of the follicles. All the structures are similar, so you can understand all the vertebrates. Thank you very much. Good luck.