 The hypothalamus is one of the most versatile structures in the human brain. It's responsible for the regulation of a wide range of bodily functions and for the synthesis of some of the body's most important hormones. Now if you haven't done much studying of the hypothalamus for step one, I think you'll actually be surprised at how specific some of the exam questions about the hypothalamus can be. You should be able to correlate the neuroanatomy of the various nuclei of the hypothalamus with their specific functions. You can see in this sagittal plane here where the hypothalamus is located within the brain. The prefix hypo, meaning beneath or below, means that the hypothalamus is located here, below the hypothalamus. You should also note that there's a direct connection with the pituitary gland. In fact, certain neurotransmitters and hormones travel directly via axons or venous blood directly to the pituitary to carry out their functions. There are a number of key functions that the hypothalamus performs that you should be aware of. These functions include hunger, thirst, the sleep cycle, body temperature, sex drive, and regulation of the autonomic nervous system. This is to say that it regulates the sympathetic and parasympathetic nervous systems. In addition to regulating homeostasis and bodily functions, the hypothalamus is also an important endocrine organ. You should also be familiar with the suite of hormones that are produced and released by the hypothalamus. These hormones are starting with thyrotropin-releasing hormone, or TRH, which in turn stimulates the release of TSH, thyroid-stimulating hormone, from the pituitary gland. Thyroid-stimulating hormone, as you might remember, will then act on the thyroid gland to release T3 and T4. The next hormone released by the hypothalamus is growth hormone-releasing hormone, or GHRH, which, as its name suggests, stimulates the release of growth hormone from the pituitary gland. The hypothalamus also releases gonadotropin-releasing hormone, also known as GNRH. Gonadotropin-releasing hormone is released by the hypothalamus and stimulates the release of gonadotropins, which are follicle-stimulating hormone, FSH, and luteinizing hormone, LH, which in turn will lead to the release of estrogens and androgens from the gonads. You also need to know that the hypothalamus synthesizes and releases somatostatin. Somatostatin is also known as growth hormone inhibiting hormone, and it acts to antagonize growth hormone. It also functions to inhibit the secretion of pancreatic exocrine hormones and gastric acid secretion. The hypothalamus also synthesizes and releases corticotropin-releasing hormone, or CRH. CRH acts on the pituitary to stimulate the release of adrenocorticotropic-releasing hormone, or ACTH. ACTH acts on the adrenoclans to stimulate the production of glucocorticoids like cortisol. The hypothalamus is also responsible for synthesizing oxytocin. Oxytocin has numerous functions, but it's best known for its role during childbirth and breastfeeding. Oxytocin is synthesized and released during childbirth in response to the baby's head coming in contact with the cervix. Oxytocin causes the uterus to contract and help to birth the baby. In fact, we often administer exogenous oxytocin to patients in order to stimulate or augment labor. It's also released in response to stimulation of the nipple gene breastfeeding and leads to expression of milk by the memory glands. Anti-diuretic hormone, also known as ADH, or vasopressin, is a hormone that acts on the collecting duct of the kidney to increase the absorption of free water, thus increasing intravascular volume, making urine more concentrated and blood more dilute. It's released in response to increase serum osmolarity in decreased intravascular volume. Oxytocin and ADH are two hormones in particular that are produced in the hypothalamus and released in the posterior pituitary, as opposed to being synthesized and produced in the hypothalamus itself. So as you can see, the hypothalamus and pituitary gland are responsible for many of the endocrine functions of the body. If this feels like a lot, or you felt like we rushed through the descriptions of these hormones, don't worry, we'll have a separate video just about the hypothalamic pituitary axis and the neuroendocrine system. Thanks again for tuning in, we really hope you enjoyed the video. Make sure you subscribe to our channel so you don't miss part two about the specific hypothalamic nuclei. That'll be coming soon.