But also through endocrine system, using substances called hormones. Hormones are generally carried to target site through blood. Posterior pituitary (which is essentially extension of hypothalamus) excites anterior pituitary to release hormones. Called neuroendocrine because cells of hypothalamus and anterior pituitary are neuronal in nature. One of the most active source of hormones. Autocrine signalling: cell release hormones and have receptor for those hormones. Each step is a potential point of regulation. Synthesis of the hormones by endocrine or neuroendocrine cells. Release of the hormones by the endocrine or neuroendocrine cells. Transport of the hormones to target site through blood. Detection of the hormones by specific receptors on target cells. Receptor can be on cell surface or even within cell (steroid receptors, glucocoticoid receptor) Removal of the hormone through physical removal, break down or short half-life. Brain: hypothalamus (posterior pituitary) + anterior pituitary gland. Parathyroid: not part of the thyroid or same.