Embedded in cartilage lacunae, the lacunae are called cartilage lacunae

Peripheral cartilage cells are immature, with small cell bodies, oblate shape, long axis parallel to the cartilage surface, and are distributed individually.

The closer to the middle of the cartilage, the more mature the cells are and the larger they are.

Mature chondrocytes have weakly basophilic cytoplasm and abundant rough endoplasmic reticulum and Golgi complex, indicating their strong ability to produce cartilage matrix.

Cells proliferate and divide into relatively concentrated groups of cells. Since they are all proliferated from the same immature cartilage cells, they are called homologous cell groups.

The main components are proteoglycans and water. Proteoglycans are similar to those in connective tissue and can also form molecular sieves with good permeability.

Material exchange within tissues with surrounding tissues through osmosis

The proteoglycan content in the tissue is higher than that of general connective tissue, thus making the cartilage matrix form a stronger gel.

Aminoglycans are unevenly distributed in the tissue, and there is more chondroitin sulfate in the area close to the cartilage lacunae, so it is highly basophilic. In HE stained sections, it looks like a capsule surrounding the chondrocytes, so it is called a cartilage capsule.

Including costal cartilage, articular cartilage, respiratory cartilage

It has strong pressure resistance, but is more susceptible to fracture than other types of cartilage under external force.

The main component is collagen fibrils composed of type II collagen, interwoven into a three-dimensional mesh.

Because the fiber is extremely thin, with a diameter of only 10-20nm, the refractive index is similar to that of the matrix, and the moisture content in the matrix is ​​high, so it is translucent.

Distributed in the auricle, throat, and epiglottis

The structure is similar to hyaline cartilage, but the fiber component is elastic fiber, so it has good elasticity

Due to the rich elastic fibers and a certain degree of acidity in the matrix, only the cartilage capsule is obviously basophilic, so it appears red and blue under a light microscope.

Distributed in intervertebral discs, articular discs and pubic symphysis, etc., with an opaque milky white color

A large number of thick collagen fibers are arranged in parallel/crisscross, so they have strong toughness

Chondrocytes are few and small, scattered, in pairs, arranged in single rows and between fiber bundles, with little amorphous matrix and weak basophilic properties.

Mesenchymal cells gather and proliferate at the site where cartilage is about to form, differentiate into osteoprogenitor cells, which then differentiate into chondroblasts, further differentiate into chondrocytes, and the surrounding mesenchyme differentiates into perichondrium.

1. Additive growth (subperichondrium growth): Osteoprogenitor cells deep in the perichondrium proliferate and differentiate into chondroblasts, and then differentiate into chondrocytes and add to the surface of cartilage tissue.

2. Interstitial growth (endochondral growth): Proliferation of existing chondrocytes to produce more chondrocytes

Including organic ingredients and inorganic ingredients, containing very little water

The extracellular matrix of new bone tissue has no bone salt deposition, which is called osteoid. A large amount of bone salt is regularly deposited and transformed into hard bone. This process is called calcification/mineralization.

Transformation from woven bone to lamellar bone

osteoprogenitor cells

osteoblast

bone cells

Osteoclasts

ring bone plate

bone unit

interosseous plate

Distributed on the medial surface of the diaphysis and the middle of the epiphysis, it is composed of a large number of trabeculae (also lamellar bone, but only a few layers)

Epiosseous membrane

endosteum