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Human Body Study

Bone Tissue

The hard connective tissue that bones are made of — living tissue, despite its rigid appearance.

The skeleton A stylised whole-body skeleton showing the axial portion (skull, spine, ribs, sternum) and the appendicular portion (girdles and limbs). A separate joint-cross-section inset gathers the tissue-level subsystems — bone tissue, cartilage and ligaments — as they meet at a joint. Each label links to the article for that part. joint cross-section Axial skeleton Appendicular skeleton Joints Bone tissue Cartilage Ligaments The skeleton — axial vs appendicular bones, with a joint cross-section showing bone, cartilage and ligaments.

Two forms

Section titled “Two forms”
  • Compact (cortical) bone — the dense outer shell.
  • Spongy (trabecular) bone — the light, lattice-like interior, often housing marrow.

Composition

Section titled “Composition”

A mineral component (mostly calcium phosphate) gives hardness; a protein component (collagen) gives flexibility and resistance to shattering.

Cells

Section titled “Cells”
  • Osteoblasts — build bone.
  • Osteocytes — mature cells that maintain it.
  • Osteoclasts — break bone down.

Key idea

Section titled “Key idea”

Bone is constantly remodeled — osteoclasts removing and osteoblasts replacing — so the skeleton continually renews itself and adapts to the loads placed on it.