The connective tissue has the function of supporting, joining and protecting other types of tissues. It has a matrix, a substrate inside which the cellular component is found which is in turn made up of specific cells (erythrocytes, leukocytes, -cysts). It is a renewable connective tissue.
The connective tissue develops from the mesenchyme embryonic tissue characterized by branched cells included in an abundant amorphous intercellular substance. Mesenchyme derives from the intermediate embryonic leaflet, mesoderm, very common in the fetus where it surrounds the developing organs by interpenetrating them. Some connective tissues of the skull derive directly from the neuroectoderm (meningeal fascia). The mesenchyme, in addition to producing all types of connective tissue, also produces other tissues: muscle, blood vessels, epithelium and some glands.
The connective tissue is morphologically characterized by various types of cells (fibroblasts, macrophages, mast cells , plasma cells , leukocytes , undifferentiated cells, fat cells or adipocytes , chondrocytes , osteocytes, myofibroblasts etc.). Immersed in an abundant intercellular material, called MEC (extracellular matrix). ECM (extracellular matrix). Synthesized from the same connective cells. MEC is composed of insoluble protein fibers (collagen, elastic and reticular). Fundamental substance, erroneously defined amorphous, colloidal, formed by soluble complexes of carbohydrates, largely linked to proteins, called acid mucopolysaccharides, glycoproteins, proteoglycans, glucosaminoglycans or GAGs(hyaluronic acid, coindroitinsulfate, keratinsulfate, heparinsulfate etc.) and, to a lesser extent, from specialized proteins , including fibronectin .
Cells and intercellular matrix characterize various types of connective tissue. Connective tissue proper ( connective tissue ), elastic tissue, reticular tissue, mucous tissue, endothelial tissue , adipose tissue , cartilage tissue, bone tissue, blood and lymph. The connective tissues therefore play several important roles. Structural, defensive, trophic and morphogenetic by organizing and influencing the growth and differentiation of the surrounding tissues.
The conditions of the fibrous part and of the fundamental substance of the connective system are partly determined by genetics. Partly by environmental factors (nutrition, exercise etc.). Protein fibers are in fact able to change according to environmental and functional needs. Of their spectrum of structural and functional variability. The integument, the basement membrane, the cartilage, the bone, the ligaments, the tendons are examples etc. The fundamental substance continuously changes its state. Becoming more or less viscous (from fluid to sticky to solid), according to specific organic needs. Found in large quantities such as joint synovial fluid and ocular vitreous humor. It is actually present in all tissues.
The connective tissue varies its structural characteristics through the piezo-electric effect: any mechanical force that creates structural deformation stretches the inter-molecular bonds producing a slight electrical flow (piezoelectric charge). This charge can be detected by the cells and involve biochemical changes: for example, in the bone, osteoclasts cannot “digest” piezoelectrically charged bone.
The extracellular matrix provides the chemical-physical environment for the cells it envelops (thus taking part in the regulation of the acid-base balance, hydro saline metabolism, electrical and osmotic balance ), forming a structure to which they adhere and within which they can move maintaining a suitable hydrated and permeable ionic environment, through which they spread the metabolites. The density of the fibrous matrix and the viscosity of the fundamental substance determine the free flow of chemicals between cells while preventing the penetration of bacteria and inert particles. Presents immune system cells (leukocytes, macrophages, mast cells, plasma cells) and is frequently the place where inflammatory processes take place. It also has great repairing capacity in areas damaged by inflammation and / or trauma, filling the spaces if necessary.
In the adipose tissue. Which constitutes a type of connective tissue. Lipids accumulate, important nutritional reserves while in the loose connective tissue water and electrolytes are preserved (thanks to its high content of acid mucopolysaccharides). About 1/3 of the total plasma proteins are in the intercellular compartment of the connective tissue
By combining a small variety of fibers within a matrix that varies from fluid to sticky to solid. The connective cells respond to the needs for flexibility and stability, diffusion and barrier.
From a mechanical point of view. The MEC (extracellular matrix) was developed to distribute. The tensions of movement and gravity while maintaining the shape of the different components of the body through the whole range of possibilities ranging from the rigidity of a continuous compression structure. To the elasticity of a tensegrity structure. In the tensegrity structure the compression parts (the bones) push out against the traction parts (myofascial) that push inwards. These types of structures have a more elastic stability than those with continuous compression and become more stable the more they are loaded.
All the interconnected elements of a tensegrity structure rearrange themselves in response to local tension. The skeleton itself is actually only apparently a continuous compression structure. As the bones rest on slippery surfaces (articular cartilages) and without myofascial support they are unable to sustain themselves. Therefore, varying the tension of the soft tissues means varying the arrangement of the bones. The minimum structural variation of an organic “angle” is transmitted mechanically and piezoelectrically. Through the tensegrity network. All the remaining body parts.
The connective tissue and muscles constitute. Anatomically and functionally. The myofascial system whose connective tissue is home to numerous sensory receptors. Including exteroceptors and nervous proprioceptors and structures. The muscles, anatomically and functionally, in myofascial chains. Thus assuming a fundamental role in the internal balance and posture system.
It is in the connective tissue network that we record posture and movement patterns through mechanical connective communication. Which affects this more than the reflex mechanisms of the neuromuscular spindles and Golgi tendon organs(proprioceptive sense organs through which the nervous system inquiries about what happens in the myofascial network). It is in fact the myofascial system actually the largest sensory organ of our organism. It is from it that the central nervous system receives mostly afferent (sensory) nerves. The presence of mechanoreceptors, in particular interstitial receptors, capable of causing effects at local and general level. It has been abundantly found in the connective tissue up to the visceral ligaments and in the cephalic and spinal dura mater (Dural sac ).
connective tissue – myofascial systemin the myofascial (muscle-fascial) system of our body. Each muscle, visceral organ, vessel (blood and lymphatic), nerve, bone, joint etc. It is enclosed in its fascial envelope. These envelopes, in turn, form a ubiquitous network of tensegrity. Which envelops and, at the same time, supports and connects all the functional units of the body. Finally, these strong elastic layers also form a surface layer. Which acts as a container and a braking support for the whole body. The surface bands placed under the skin.
The muscle is held in place through connective laminae (aponeurosis or aponeurosis) and is enclosed in the bands like the pulp of an orange. It is in the cell walls that divide it (epimysium, perimysium and endomysium). Local “obstructions”, such as fascial adhesions can result from excessive efforts or lack of exercise. Trauma, inflammatory diseases, adhesion scars etc. In the presence of fascial adhesions in the different fascial layers. There is an increased internal friction that counteracts movement. In particular, muscle stretching. This creates a traction of the adjacent structures which contributes to fatigue and general tensions.
In addition, a muscle that works persistently in shortening. In addition to modifying the quality and quantity (based on the forces acting on it and the available spaces). The connective tissue portion can decrease. The number of sarcomeres (on the contrary, a muscle that works in lengthening tends to increase the connective part and the number of sarcomeres); this creates the formation of a retracted muscle . The elimination of these impediments and therefore the restoration of the correct flow allows the cells concerned to pass from a survival metabolism to a specific physiological one.
The discovery of the presence of connective tissue cells interposed with collagen fibers fascial is with contractile capacities similar to smooth muscles, called myofibroblasts , has demonstrated the ability of the connective tissue to contract in certain situations.
Regular dense connective tissue
The dense (or compact) regular connective tissue can be found above Regular dense (or compact) connective tissue all in the structures subjected to traction. In one direction (tendons, ligaments, aponeurosis and fascia’s) and in the stroma of the cornea. In the tendons and ligaments. The collagen bundles are tightly packed together and all oriented in the direction of traction. The amorphous fundamental substance is very scarce. The only cells present are fibroblasts arranged in long parallel rows in the interstices between the bundles of collagen fibers. Where elastic nets are often interposed. Tendons are made up of smaller tendon bundles joined together by poor loose connective tissue.
In the fasciae and aponeuroses. The collagen fiber bundles have a less regular orientation than that of the tendons.
The connective tissue stroma of the cornea is characteristic. It is made up of several layers of collagen fibers with the fibers of one layer oriented. Approximately perpendicularly to those of the contiguous layer.
Connective tissue proper
- Lasso: The matrix (or fundamental substance) is very fragile and mainly consists of collagen (α-helix trimer). It is mainly used to wrap the organs and separate them from neighboring ones.
- Fibrous: The matrix is much denser and is made up of collagen. Elastin and in greater percentage fibrin (two proteins) which make it resistant and elastic. It is a support and connection structure between bone and musculature (eg Tendons).
- Elastic: In this case, elastin prevails in% which therefore gives this fabric particular elastic properties. (eg. The ligaments).
Supportive connective tissue
- Cartilaginous: The cells that form it are called: chondrocytes. The matrix is semi solid, very viscous but still elastic. The main functions:
- shock-absorbing pads: (joints; intervertebral discs);
- make certain parts of the body elastic (e.g. auricle, nose);
- Skeletal: It is composed of osteocytes. Osteoblasts and osteoclasts (cells capable of dissolving and reconstructing the bone matrix). The matrix contains oxen and is mineral (formed from calcium and magnesium phosphate). The histological structure of the bone tissue is the osteon formed by osteocytes. Surrounded by concentric blades of matrix.
Fluid connective tissue: characterized by a fluid matrix.
- Blood: (matrix: plasma) with the function of connecting all parts of the body. Formed by:
- Red blood cells (erythrocytes) which have the function of transporting oxygen and are rich in hemoglobin.
- White blood cells (leukocytes) that take different names depending on the function they perform. The function is however linked to that of the immune system.
- Platelets (truncated cells) that thanks to thrombin (protein) allow blood clotting. (platelet cap).
- Lymph: has a lipid substance as matrix, through which lipids and white blood cells are distributed.
- Adipose tissue: it has a reduced matrix as it is occupied by adipocytes. It has an insulating, shock absorbing and energy reserve function (triglycerides).
The technical advancement of electron microscopy has shown that the cell is far from a membranous sac containing a solution of molecules, as previously believed. The cell is actually full of filaments, tubes, fibers and trabeculae forming a structure called cytoplasmic matrix or cytoskeleton. There is very little space available to allow the random diffusion of molecules. Moreover very little water is present in the free state being almost totally in the state of solvation. As it happens for the connective tissue.
The cytoskeleton is mostly made up of actin microfilaments. A globular protein, and tubulin microtubules, a tubular protein. Microtubules and microfilaments are spontaneously formed and disintegrated. When particular environmental conditions arise (e.g. presence of Ca2 + and Mg2 +).
Already at the beginning of the eighties the role of the cytoskeleton in the support of the cell was understood. In allowing the movements of the cell itself and of the vesicles and its implication in the processes of cell division. It is show that the extracellular matrix is linked to the cytoskeleton system. So as to keep our body together. Today we know that these bonds affect physiological processes such as embryonic development, blood clotting, wound healing etc.