Male and female reproductive system

Created April 2020, Offline version here
Video by Paul Anderson, also on his website Bozeman Science.

    Whereas some organisms reproduce , humans and most animals reproduce by sexual reproduction. The main benefit of sexual reproduction is that it generates genetic . This is important for the fitness of a species. Sexual reproduction involves the combining of two , the sperm cell and the egg cell. This is made possible by the specialized reproductive cells in males and females. In males, sperm cells are formed in the , which also secrete sex hormones such as testosterone. Sperm cells develop and mature as they are transported through the . The sperm are then transported from the epididymis to the ejaculatory ducts through a tube called the in preparation for . Along the way, secretions are collected from secondary sex glands such as the seminal vesicles, , and the Cowper’s gland. These secretions act to provide nutrients and neutralize the pH inside the . Ultimately, they create an optimal environment for the sperm to the egg. In the female reproductive system, the release an egg,also called an . This occurs through the process of ovulation. Ovulation is controlled by two hormones, FSH and . These hormones are secreted by the . Once a month, one of the eggs develops into a . The follicles mature and grow, releasing the egg at the point of . These processes are controlled by the actions of hormones. The levels of the hormone estrogen rise slightly prior to ovulation. The hormones FSH and LH peak at the point of ovulation. Following ovulation, levels increase. Estrogen and progesterone induce the of the endometrium lining. After the egg is released, it travels down the . If no fertilization takes place, the lining of the uterus is during the process of menstruation. If the egg is fertilized, by a sperm cell, it in the uterus. The zygote then undergoes multiple cell divisions, eventually forming a mass of cells called a ,which then forms a gastrula. A gastrula has three layers of cells: the endoderm, the , and the ectoderm.