Assertion: endosteum's osteoblast | /r/LocatedNear | the ecm
Facets:
Source sentences:
text: osteoblasts are surrounded by the ECM that they secrete to become osteocytes; small cavities that are filled with extracellular fluid located between lamellae; about 20,000-30,000 osteocytes and lacunae are found in each cubic millimeter of bone