Have you ever considered the differences between male and a female appearance? Without even realizing you can simply distinguish between the two, isn’t it. Well we are born with some primary characters such as males are born with penis and female are born with vagina. But on the other hand there are some more characters which are known as secondary sexual characteristics which appear or it starts appearing during the puberty .These characters, they help you in distinguishing between the male and female. So in this lesson we are going to discuss about those secondary sexual character and their cause. Secondary sexual character are those characters, those physical characters which appear during the adolescence which starts appearing during the adolescence and they help you to distinguish between the male and the female. However these characters they are not directly involved in reproduction. So let’s just discuss some of these characters in male. Male, they begin to show a pronounced hair characteristics. So like they grow a beard , they grow moustache and also they show some hair on their chests. They also develop some heavy musculature. Right? While in females, they start developing breasts, they have less pronounced hair on the body and they also have lighter musculature. So all these characters, they are helping it distinguishing between the two. But they have some common characters also. So for example both of them, they start developing hair under their arms on the region above their thigh and also in the pubic region. So all these characters are the secondary sexual character, but what initiate these secondary sexual character? How do they actually appear? These characters, they are initiated by the hormones. Hormones are those chemical substances which are released by the glands. So glands are nothing but simply the organs of your body which are assigned to secrete these chemicals or hormones. Now all these hormones which are linked with the secondary sexual characters, they are released by some special category of glands which are known as endocrine gland. Endocrine glands are those gland which release or secrete. Their secretion of hormones directly into the blood stream. So you do not have any doubts or anything. They simply make the hormones in them and as soon as they prepared this hormone, they directly secrete into the bloodstream. Like as we know, the blood it circulates everything throughout the body. Similarly here also the blood circulates hormones throughout the body, but does these hormones, they act upon the whole body? Well , No. Hormones are assigned to function or to bring changes only on their target site. So whatever gland it is whatever Hormone is producing it has to have a target site. While talking about let’s say the secondary sexual character, you know that males, in males testis is their reproductive organ. Similarly in females, ovary is their reproductive organs. These two are the endocrine glands. So for example we can now say that testis in male, it produces a hormone called as testosterone. Testosterone the male sexual hormone. Similarly in females, the ovaries they produce a hormone called as estrogen. This estrogen is a female sex hormone and both these hormones like testosterone and estrogen, they both helped in occurence or developing those secondary sexual character. Now while talking about these gland, you have just seen that they are bringing all these changes in males and females but similar to our classroom. Like your classroom, it is the whole classroom, it is controlled by a single class teacher, right? Similarly all these glands, all these endocrine glands they are all controlled by a single master gland and the single master gland is what you call pituitary gland. Pituitary gland can also be now called as a master gland. It as, it is controlling all the various gland of your body. So this pituitary gland, it basically secrets some stimulating hormone. Ok the stimulating hormone stimulates or activates the various glands of your body. So this pituitary gland which is present around or which is present very close to the brain, it secretes like I said some stimulating hormone and these hormones they activate the various glands. For example in here is activating testis and ovary. So once it activates the testis, the testis starts producing testosterone in male. Similarly when it activates ovary in females, it starts producing estrogen. Now this testosterone and estrogen they get mixed in the blood and basically circulates throughout the body. But it bring changes only in their specific parts. For example like in male it can bring changes where you want hairs or in let’s say in females it is bringing about change in the breast. So these are the changes which occur with the help of pituitary gland. So students in this lesson you have understood like what are the secondary sexual characteristics, which are nothing but the physical changes which occur or which starts occurring during the adolescence and they help in distinguishing the male and female appearance. Similarly you have learned that hormones are those chemical substances which are released by the glands and these glands are again nothing but the organs which are assigned to produce these hormones. All these glands like we just discussed like testes and ovaries they are all controlled by a master gland called as a pituitary gland Pituitary gland it activates this gland like testes and ovary to produce their hormones like testosterone and estrogen and these hormones they bring about those changes in your body which you call the secondary sexual character.