Labels:text | screenshot | black | black and white OCR: Changes in blood tonicity are recogni ed in the osmotically sensitive cells that are sit circumventricular organs of the ante organ hypothalamus, probably the subforni amina and/or the organum vasculosum of tence of terminalis. There is evidence for the two distinct osmoreceptors: one contr ne vasopressin secretion, principally fro thirst supraoptic nucleus; the other that ser appreciation (Fig. 5.3).