Conjunctive Fabric

The conjunctive fabrics ( TC ) are fabrics of which cell S is separated by extracellular matrix , contrary to the epithelium S where the cells are jointed. These fabrics, completely absent in the most primitive animals constitute the majority of the mass of the body of the advanced organizations (2/3 of total volume at the man). They are implied in the functions of support, protection, movement, immunizing response and growth…

Components

All the conjunctive fabrics are formed by an association of three elements: cellular elements, fundamental substances and fibers.

Cellular elements

Indigenous cells: the Fibroblast S, have an aspect in faisseau with many prolongations. They are rich in organoids because they have an important role of synthesis. It is them which work out the two other components of this fabrics. One also finds in conjunctive fabrics of the cells in transit. They belong mainly to the immune system of the organization: (Macrophage, Granulocyte, Lymphocyte, etc)

Fundamental substances

The Fibroblastes produce endogenous substances: proteins associated with glucidic chains: the Protéoglycane S. These protéoglycanes is associated with a Acide to form a trap with water. The nutritive role is ensured by water, rock salt and Protéines which one finds in abundant quantity. These substances also contribute to the shock protection and the compactions which could undergo the bodies.

Fibers

One finds in conjunctive fabrics three types of fibers:

fibers of Collagenous (1 to 12 micrometer)

It is a substance made up of a basic molecule: the Collagenous, those can agglomerate between them and gives long and sinuous collagen fibers having a great resistance without elasticity.

fibers of Réticuline (0,2 to 2 micrometer)

Element fibrillary which can be forked and be anastomosed, dense inextensible and flexible (high content in cement: Glycoprotéine) or one finds elementary collagen fibrillae of the type III.

elastic fibers (0,2 to 1 micrometer)

They offer a capacity of extension and contraction (120% to 150%), while preserving a great resistance. Two components are observed:

an amorphous component: elastin, scleroprotein, polymer insoluble, hydrophobic, precursor of the tropoèlastine.
like that a component fribrillaire: fibers oxytalanes, containing collagen IV and lipoproteins.

Classification

The conjunctive fabrics consist of cells and extracellular matrix, which is itself made up of fibers (Collagène, Réticuline or elastin) and of fundamental Substance. One classifies conjunctive fabrics according to the prevalence of one of these three components:

Loose conjunctive fabrics

These fabrics are with prevalence cellular and are interesting because containing properties of excretion of substance coming from collagen fibers. Example: fabric palléal of the center

Dense conjunctive fabrics

These fabrics are with prevalence fibraires and ensure a mechanical role.

prevalence of collagen: fibrous conjunctive fabrics.

not directed. Example: deep Derm
directed
unitendu. Example: tendon S
bitendu. Example: Cornea
semi-directed, i.e. mixing with the fibrous dense conjunctive fabric zones directed and with the fibrous dense conjunctive fabric zones not directed. Example: the derm.

prevalence of réticuline: reticular conjunctive fabrics. Example: bodies hematopoietic
prevalence of elastin: elastic conjunctive fabrics. Example: Cartilage of the Ear, the épiglotte

Œdémateux conjunctive fabrics

These fabrics are with prevalence of fundamental substance. The Gelée of Wharton in is an example.

Fat conjunctive fabrics

It consists of nombeuses adipocytes containing an enormous lipidic vacuole. One finds it in the Derme or the Mésentère. He plays 3 parts:

thermal protection (the lipids are good insulators against the cold)
mechanical protection (shock absorbers of the shocks)
energy reserve

Principal conjunctive fabrics

These fabrics include/understand:

the Mésenchyme S or conjunctive fabrics of support. As their name indicates it, these fabrics are purely of support. Their characteristic cell is the Fibroblaste, thus named because it secret the greatest part of the extracellular Matrice existing in the organization. These fabrics constitute large membranes, rich in fibers of Collagène and limited by a layer of the epithelial type on each face (the Mésothélium). They separate the various compartments from the Cœlome of the animals and also have a function of support: they are rolled up around the bodies and maintain them in place.
the muscular fabric is made of Syncitium (cell resulting from the fusion of several cells and comprising several cores). The matrix is particularly reduced there, but each cell in spite of is very surrounded by it (it is thus well conjunctive). These cells are contractile and are implied in all the movements which can occur there. In the animals diploblastic which do not have the conjunctive ones, their function is dealt with by specialized epithelial cells of the Ectoderme.
the Cartilage is a conjunctive fabric rich in collagenous II. Because of its solidity, it is used as skeleton at the primitive Vertébré S (Poisson S Chondrichtyen S).
the Os has an extracellular matrix contains in particular collagenous I which guarantees its cohesion and of the crystals of Hydroxyapatite which guarantee its solidity. It constitutes the Squelette light and very resistant which characterizes the majority of vertebrate and is certainly in very great part responsible for their evolutionary success. It has also like function to constitute a calcium reserve (fundamental Ion for cellular operation), which explains the dynamic operation (with destruction and perpetual rebuilding) of the bone at the vertebrate ones.
the Sang is a liquid conjunctive fabric. It circulates inside the blood-vessels and makes it possible to bring the various molecules of the organization of the place where they are available towards that where they are used.

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