Binders

Connective tissueconsists of cells and the intercellular mass in which these cells are embedded.

All connective tissues have a mesenchymal origin, from which the following tissue types are differentiated:
 * Ligament (different types)
 * Cartilage (3 types, chondrocytes, chondroblasts)
 * Bone (osteocytes, osteoblasts)
 * Dentin(tooth, odontoblasts)
 * Cement (tooth, cementoblasts, cementocytes)

Connective cells
Connective cells form different types of cells depending on the type of connective tissue. These include fibroblasts, fibrocytes, odontoblasts, osteoblasts and chondroblasts.

Extracellular matrix (ECM)
ECM is produced by the cells of a given tissue type. It consists of macromolecules that form a complexly organized network. Cells have binding sites, receptors for ECM used to attach cells to ECM and to regulate their activity. The ECM is a colorless, transparent, gel-like substance in which cells and fibers are embedded. We divide the matrix into fibrous component and component amorphous.

Collagen fibers
Collagen fibers are 1–20 μm long. The properties of the collagen fiber include strength and flexibility. They tend to form bundles.They are produced by tissue cells, but also by smooth muscle cells, glial cells, adipocytes and epithelia. About 21 types are known collagen, which differ in sequence and type of amino acid in the chain.

The most well-known types of collagen include:
 * collagen I (75 nm fibrils, bundles of fibers, we can see with the eye, most widespread in the body, occurrence in fibrocartilage)
 * collagen II (thin fibrils 20 nm, separate, without bundles, hyaline and elastic cartilage)
 * collagen III (45 nm fibrils, reticular fibers)
 * collagen IV (in lamina basalis)

Collagen fibers are eosinophilic (acidophilic) and can be stained with eosin, light green, aniline blue, saffron, or picrofuchsin. Collagen synthesis takes place on GER ribosomes. The protein follows a route to the Golgi complex where it is hydroxylated and glycosylated. Here it is also packed in pouches without a membrane, the so-called vesicles and by exocytosis it is then sent out of the cell in the form of a protocolagen molecule (3 polypeptide chains with registration peptides at the ends of the chain that prevent polymerization). It produces protocologen-peptidases and cleaves the registration peptides. A tropocollagen molecule is formed, which can now polymerize and form collagen myofibrils. Collagen fibrils can then form and polymerize into the final collagen fiber.

Reticular fibers
They are made of type III collagen. The fibers are 0.2–2 μm long and are made up of 45 nm fibrils. They form networks in bodies. They are colored by silver impregnation (argyrophilic), PAS reaction (they have a lot of glycoproteins and proteoglycans),Gomori's impregnation.

Elastická vlákna
Elastická vlákna|thumb|150px Elastická vlákna jsou tenčí než kolagenní vlákna. Mají délku 0,5–4 μm. Centrální protein tvoří elastin a okolní mikrofibrily. Jsou elastická, tvoří sítě, anastomózují a větví se. Elasticita je zajištěna díky hydrofóbní vlastnosti. Jsou produkována fibroblasty. Barví se speciálními barvícími metodami, jako je orcein, resorcin-fuchsin a aldehyd-fuchsin.

Amorfní složka ECM
Tvořena převážně vodou a ionty. Najdeme zde také glykosaminoglykany (GAG), které tvoří velké nerozvětvené polysacharidové řetězce. Tyto řetězce jsou složené z disacharidových jednotek a mají negativní náboj. Jedná se o aminocukry N-acetylglukosamin, N-acetylgalaktosamin,které jsou často sulfonované. U mnoha GAG je součástí molekuly druhý cukr, kys. uronová s karboxylovou skupinou. GAG jsou vysoce hydrofilní a udržují architekturu ECM. Zabraňují její deformaci kompresními silami díky: kyselině hyaluronové, chondroitin sulfátu, dermatan sulfátu, heparan sulfátu a heparinu, keratan sulfátu a proteoglykanům. S výjimkou kyseliny hyaluronové se GAG kovalentně váží k proteinu a tvoří proteoglykany − veliké molekuly schopné udržovat vysokou hydrataci ECM. Další část amorfní složky tvoří adhesní proteiny. Jako příklad můžeme uvést fibronektin, který je multifunkční glykoprotein a váže se k receptorům (integriny) na povrchu buněk nebo laminin, který je sulfonovaný glykoprotein v bazální lamině.