EM Initrogenous-hormone secreting cell feature /granules: contain calcitonin function secret calcitonin/ to promote activity of osteoblast and suppressing the absorption of Catt in gastrointestinal tract and renal tubule secret calcitonin gene related peptide CGRP(act upon heart and small Bv) and somatostatinEM: /nitrogenous-hormone secreting cell feature /granules: contain calcitonin ---function: i. secret calcitonin to promote activity of osteoblast and suppressing the absorption of Ca++ in gastrointestinal tract and renal tubule ii. secret calcitonin gene related peptide, CGRP(act upon heart and small BV) and somatostatin