[Music] in this video we're going to discuss the sexual development of males and females so at the onset of puberty is when the changes really begin to occur in particular the hypothalamus begins to release pulses of gonadotropin releasing hormones and this is going to have different effects on males and females so first of all in males the hypothalamus when it secretes gnrh these pulses have a constant frequency so secreted at a constant frequency the nanotropic releasing hormone is going to act on the anterior pituitary gland of males to cause the release of luteinizing hormone as well as follicle stimulating hormone fsh and lh now lh and fsh are going to act on the testes and this is going to result in spermatogenesis the production of sperm cells it's also going to result in the release of testosterone and this is also going to result in secondary sex characteristics of males so during puberty is when males start to undergo these changes these include the growth of body hairs in different regions of the body enlargement of the larynx which results in a deepening of the voice the broadening of the shoulders and many other changes that are all secondary sex characteristics of males now another thing to know about these results of lh and fsh acting on the testes is testosterone itself is a hormone right it's a hormone important in producing these secondary sex characteristics but testosterone also has other actions in particular testosterone inhibits the hypothalamus and anterior pituitary this is a type of negative feedback so essentially testosterone when it is released it itself is going to inhibit the hypothalamus from releasing gnrh and also inhibit the antiretroviral pituitary gland from releasing fsh and lh okay so this is males so now let's take a look at females so in females we have the same start at the onset of puberty the hypothalamus is going to start releasing pulses of gnrh the difference between males and females is in males the gr pulses are at a constant frequency throughout their life for females the frequency of the pulses varies depending on the menstrual cycle so that means that some periods of the menstrual cycle there are going to be a higher frequency of gnrh pulses in other periods where there is a lower frequency of gnrh pulses gonadotropin-releasing hormone is similarly going to act on the anterior pituitary to cause the release of lh as well as fsh lh and fsh are going to act on the ovaries to stimulate folliculogenesis this is the maturation of the follicle so the gamete produced by the ovaries are in follicles the follicles initially are very small but with lh and fsh they're going to mature and develop into larger structures which we're going to discuss in more details in subsequent videos in addition the ovaries lh and fsh and leading to maturation of the follicle is going to result in the release of estrogen as well as progesterone now estrogen is also important because it's going to result in the development of the secondary sex characteristics of females so similar to males at the onset of puberty they're going to be changes that occur specifically in females so this would also include the development of hair in different parts of the body the growth of breasts the widening of the hips and additional changes now estrogen and progesterone they're going to have very important functions in the menstrual cycle and pregnancy which we'll discuss again in subsequent videos but similar to testosterone estrogen and progesterone also have an inhibitory function on the anterior pituitary as well as the hypothalamus so again this is a form of negative feedback where the release of estrogen and progesterone actually inhibits the release of gnrh from the hypothalamus and lh and fsh from the anterior pituitary now for females it's a little bit more complicated because again this process undergoes changes during the menstrual cycle so in subsequent videos we're going to discuss how the secretion of fsh lh estrogen and progesterone varies during the female reproductive cycle