佝偻病维生素d缺乏（Rickets of vitamin D deficiency）ppt课件.pptVIP

Rickets of vitamin D deficiency;Rickets;Vitamin D;Ergosterol 麦角甾醇;1-alpha-hydroxylase ↑ ;Vitamin D ;Each of the forms of vitamin D is hydrophobic, and is transported in blood bound to carrier proteins, mainly vitamin D-binding protein. The halflife of 25-hydroxycholecalciferol is several weeks, while that of 1,25-dihydroxycholecalciferol is only a few hours. ;1,25-dihydroxycholecalciferol ;The Vitamin D Receptor and Mechanism of Action; ??????????????????????????????????????????????? ;Effects of Vitamin D on intestine ;Effects of Vitamin D on bone;vitamin D receptors are present in most if not all cells in the body. potent effects on the growth and differentiation of many types of cells in vitro. physiologic effects much broader other than mineral homeostasis and mineralization of bone This is an active area of research and a much better understanding of this area will likely be available in the near future. ;Parathyroid hormone;Calcitonin;Causes of vitamin D deficiency;Bone metabolism;Bone growth ;Vitamin D–deficient rickets can be conceptualized as the bodys attempt to maintain normal serum calcium levels，which results in halted bone mineralization ; ;mechanism of bone deformities; Line tests in rats (proximal end of the tibia) (calcified tissue stained with silver appears black). A, Active rickets. The light broad zone between the epiphysis and the shaft represents the rachitic metaphysis (R.M.佝偻病骨骺) C = cartilage; O = osteoid. B, Healing rickets. The line of preparatory calcification (L.P.C.) between the zone of cartilage (C) and the osteoid (O). C, Healed rickets. Cartilaginous disc (C) between the epiphysis and the normal shaft. ;Clinical manifestation;Bone deformities;Palpable enlargement of the costochondral junctions (rachitic rosary) in a young infant ;Deformities in rickets, showing the curvature of the limbs, potbelly, and Harrison groove. ;Diagnosis;Radiography of bone;A: Active rickets; cupping and fraying of the distal end