Biology — Vitamin D Activation

{
  "elements":[
    {"data":{"id":"skin","label":"Skin (7-DHC)"}},
    {"data":{"id":"d3","label":"Vitamin D3"}},
    {"data":{"id":"liver","label":"Liver: 25-OH-D"}},
    {"data":{"id":"kidney","label":"Kidney: 1,25-(OH)2-D"}},
    {"data":{"id":"ca","label":"Calcium absorption"}},
    {"data":{"source":"skin","target":"d3","label":"UVB"}},
    {"data":{"source":"d3","target":"liver"}},
    {"data":{"source":"liver","target":"kidney"}},
    {"data":{"source":"kidney","target":"ca","label":"active form"}}
  ],
  "layout":{"name":"breadthfirst","directed":true}
}