Final answer:
Oxytocin and vasopressin are synthesized in the hypothalamus, stored in the posterior pituitary gland, and released into the circulatory system.
Step-by-step explanation:
The synthesis of oxytocin and vasopressin (also known as Anti-diuretic Hormone or ADH) occurs in the hypothalamus. These hormones are produced by specific neurons in the hypothalamus, with oxytocin produced by neurons in the paraventricular nuclei, and vasopressin produced by neurons in the supraoptic nuclei. After their synthesis, these hormones are transported down the axons and along the infundibulum to the posterior pituitary gland, where they are stored and later released into the circulatory system. It's important to note that the posterior pituitary does not produce these hormones; it only stores and releases hormones produced by the hypothalamus.