few

Gel-like (semi-solid)

Protein polysaccharides and water

Cavity-cartilage

No blood vessels, strong permeability

Different cartilage content and types are different

Single, paired or arranged in a single row

Distributed between fiber bundles

Substrate

fiber

Substrate

fiber

fiber

Amorphous matrix

Outer layer

Inner layer

The surface & inside of the backbone

External ring bone plate

Inner ring bone plate

Pass through pipe

Central management

Bone unit bone plate

Bone tubules

Main: Osteoprogenitor cells

Large cell body, columnar or elliptical, strong basophilic cytoplasm, round nucleus, mostly located at the free end of the cell

Rich coarse endoplasmic net

Gorgi complex

Large size, many cytoplasm, eosinophilic, and many nuclei

There are lysosomes in the cytoplasm with fold margins (microvilli) on the side of the bone

There are few cell organelles around the fold edges and low electron density, forming bright areas

The bright area forms a carriage-like shape, which facilitates osteoclasts to function in a closed environment

Release of water alkali enzymes and organic acids

Small, flat and oval, located in the bone trap (containing tissue fluid)

Elongated, located within the bone tubules (meet each other, link the gap)

Also known as bone glue fiber

Chemical composition

Also known as bone salt

Calcium and phosphorus

Electron microscope

Cancellous bone

Tight bone