Other Hormones and Their Effects

• Pineal Gland: A small pine cone-shaped endocrine gland situated in the mid-region of the brain, composed of masses of neuroglia and secretes melatonin, an amine-derivative hormone of serotonin.
• Melatonin: Controls the body’s biological clock and regulates the sleep-wake cycle, secreted in darkness to promote sleepiness.
• Thymus: A prominent hormone, thymosin, contributes to the maturation of T cells or T lymphocytes, a type of white blood cells that destroy microbes and foreign substances, and can also destroy infected or cancerous cells, retard the process of aging, and occur early in development, but gradually become smaller and less important as a person matures.
• Gonads: Gamete-producing organs, testes for males and ovaries for females, that produce sperm cells and oocytes, and are mixed-function organs.
• Ovaries: Paired, oval-shaped structures located in the pelvic region, that secrete estrogen and progesterone.
• Interaction of the ovaries with the FSH and LH of the APG and the GnRH of the hypothalamus: Regulate the menstrual cycle, maintain pregnancy, and prepare the mammary glands for lactation.
• Estrogen hormone types: Estradiol, the primary estrogen produced during a female’s reproductive years, Estriol with a more prominent role during pregnancy, and Estrone with a more prominent role after a woman undergoes menopause.
• Estrogens contribute to the development of secondary sex characteristics in females, the promotion of follicles during the menstrual cycle, the release of secondary oocyte during ovulation, and the initiation and promotion of the growth of breasts and uterus.
• Progesterone maintains the lining of the uterus for a possible pregnancy, promoting fat use for energy, regulating blood sugar levels, normalizing blood clotting, and has antidepressant functions.
• Testes: Oval glands in males that are housed within the scrotum, that secrete testosterone, the male sex hormone, which descends outside of the body before birth because the abdominal temperature is not optimal for sperm production, regulates the production of sperm cells, and stimulates the development and maintenance of male secondary sex characteristics, such as beard growth and deepening of the voice.