In the human body there are several different kinds of tissue.They all play a role in our life.One of the most important is the connective tissue.Its share is about 50% by weight of a person.It represents a link that connects together all the tissues of our body.From its state depends on many of the functions of the human body.The following discusses various types of connective tissue.
General
connective tissue structure and function of which have been studied for centuries, responsible for the operation of many organs and systems.Its specific gravity is from 60 to 90% of their weight.It generates a reference frame called stroma and integument bodies called the dermis.The main features of connective tissue:
- common origin from the mesenchyme;
- structural similarity;
- perform support functions.
main part of a solid connective tissue refers to the fibrous type.It consists of elastin and collagen fibers.Together with the epithelial connective tissue is an integral part of the skin.At the same time it unites it with the muscle fibers.
Connective tissue is very different from others in that it is presented in the body of 4 different states:
- fiber (ligaments, tendons, fascia);
- hard (bone);
- gel (cartilage, joints);
- fluid (lymph, blood, intercellular, synovial, cerebrospinal fluid).
also representatives of this type of fabric are: sarcolemma, fat, extracellular matrix, iris, sclera, microglia.
structure of connective tissue
It includes fixed cells (fibroblasts, fibroblasts) comprising a basic substance.It is also a fibrous formation.They represent the intercellular substance.Furthermore, it contains various free cells (fat, wandering, obese and others.).Connective tissue is composed of the extracellular matrix (base).Jelly-like consistency of the substance due to its composition.Matrix is a highly hydrated gel formed by high-molecular compounds.They make up about 30% of the weight of the intercellular substance.At the same time the remaining 70% is water.
Classification of connective tissue
classification of this type of tissue is complicated by their diversity.Thus, its main types are classified, in turn, has several separate groups.There are such types:
- Actually connective tissue, which is isolated from the fiber and specific, different special features.The first is divided into: loose and dense (non-discharge and clearance), and the second - in the fat, reticular, mucous, pigment.
- skeletal, which is divided into cartilage and bone.
- trophic to which the blood and lymph.
Any connective tissue determines the functional and morphological integrity of the body.She has such characteristic features:
- tissue specialization;
- versatility;
- multifunctionality;
- ability to adapt;
- polymorphism and multicomponent.
General functions of connective tissue
Different types of connective tissue following functions:
- structural;
- ensure water-salt balance;
- trophic;
- mechanical protection of the bone of the skull;
- formative (for example, the shape of the eye is determined by the sclera);
- ensure continuity of tissue permeability;
- musculoskeletal mechanical (cartilage and bone, aponeuroses and tendons);
- protective (immunology and phagocytosis);
- plastic (adaptation to new environmental conditions, wound healing);
- homeostatic (participate in this important process of the body).
In general terms, the function of the connective tissue:
- giving the human body shape, stability, strength;
- protection covering internal organs and the connection between them.
main function contained in the intercellular substance connective tissue support.It provides a basis for normal metabolism.Nervous and connective tissue and provides the interaction of various body systems and their regulation.
structure of various kinds of fabrics
structure of connective tissue varies depending on its type.It consists of various cells and the intercellular substances.A distinctive feature of this fabric - high regenerative capacity.It is characterized by ductility and good adaptation to changing conditions.Any kind of connective tissue grow and develop at the expense of reproduction and transformation of young undifferentiated cells.They are derived from mesenchyme that are embryonic tissue formed from the mesoderm (middle germ layer).
intercellular substance called extracellular matrix, contains many different compounds (inorganic and organic).It is on their composition and amount and depends on the consistency of the connective tissue.Such substances as blood and lymph contain in its composition intercellular substance in liquid form, called plasma.Cartilage matrix has the form of a gel.Intercellular substance bone and tendon fibers are solid insoluble materials.
extracellular matrix is represented by proteins such as elastin and collagen, proteoglycans and glycoproteins, glycosaminoglycans (GAGs).Its members may include structural proteins laminin and fibronectin.
Loose and dense connective tissue
These types of connective tissue contain in the structure cell and extracellular matrix.In their loose much more than dense.The latter is dominated by the various fibers.The functions of these tissues and cells are defined by the ratio of the intercellular substance.Loosely-connective tissue performs mainly trophic function.She also participates in supporting mechanical activity.Cartilage, bone and hard-fibrous connective tissue in the body perform musculoskeletal mechanical function.The rest - trophic and protective.
loose fibrous connective tissue unformed
Loose fibrous connective tissue, structure and function are determined by its cells, it is found in all organs.In many of them it forms the base (stroma).It is composed of collagen and elastic fibers, fibroblasts, macrophages, plasma cells.This fabric is accompanied by the vessels of the circulatory system.Through its loose fibers occurs metabolism of blood cells, in which a transition occurs nutrients from it in the tissue.
The intercellular substance is 3 kinds of fiber:
- Collagen that go in different directions.These fibers have the form of straight and wavy strands (banners).Their thickness is 1-4 microns.
- Elastic that is slightly thicker collagen fibers.They are connected (anastomose) with each other, forming shirokopletistuyu network.
- Reticular characterized by their thinness.They are intertwined in the mesh.
cellular elements of the loose fibrous tissue are:
- fibroblasts, which are the most numerous.They have a spindle shape.Many of these are equipped with spikes.Fibroblasts are able to reproduce.They take part in the formation of the main substance of this type of fabric, as the basis of its fibers.These cells produce collagen and elastin, as well as other substances of the extracellular matrix.Inactive fibroblasts called fibrocytes.Fibroklasty - are cells that can digest and absorb extracellular matrix.They are mature fibroblasts.
- Macrophages, which can be round, elongated and irregular shape.These cells can consume and digest pathogens and necrotic tissue, neutralize toxins.They are directly involved in the formation of immunity.They are divided into gistotsity (being at rest) and free (vagus) cells.Macrophages are distinguished by their ability to amoeboid movements.According to their origin they are blood monocytes.
- fat cells can accumulate in the cytoplasm of the buffer stock in the form of drops.They are spherical in shape and can displace other structural units tissues.This forms a dense fatty connective tissue.It protects the body from heat loss.In humans, the adipose tissue is mostly under the skin between the internal organs in the gland.It is divided into white and brown.
- plasma cells found in the tissues of the intestine, bone marrow and lymph nodes.These small structural units are distinguished by their round or oval shape.They play an important role in the defense system.For example, in the synthesis of antibodies.Plasma cells produce globulins blood plays an important role in the normal functioning of the body.
- mast cells, tissue basophils are often called, are characterized by their grit.In their cytoplasm contains special granules.They come in different shapes.These cells are located in tissues of all organs, with a layer of loose connective tissue unformed.They include substances such as heparin, hyaluronic acid, histamine.Their direct purpose - the secretion of these substances and the regulation of the microcirculation in the tissues.They are considered immune cells of the type of tissue and are responsible for any inflammatory and allergic reactions.Tissue basophils concentrated around blood vessels and lymph nodes under the skin to red bone marrow, spleen.
- pigment cells (melanocytes) that are highly branched form.They contain melanin.These cells are found in the skin and iris.By origin distinguish ectodermal cells, as well as derivatives of the so-called neural crest.
- Adveptitsialnye cells, which are located along blood vessels (capillaries).They differ in their elongated shape and have a central core.These structural units can proliferate and be converted to other forms.It comes at their expense replenish the dead cells of the tissue.
dense fibrous connective tissue
By the connective tissue is the fabric:
- Thick unformed, which consists of a large number of closely spaced fibers.It also includes a small number of cells disposed therebetween.
- Thick decorated with a distinct arrangement of connective tissue fibers.It is the basic building blocks of ligaments and other structures in the body.For example, tendon formed by closely spaced parallel puchochkami collagen fibers, the space between which is filled with a basic substance and a thin elastic network.Tightly-fibrous connective tissue of this type contains only cells fibrocytes.
recovered from it yet elastic fiber that makes up some bundles (voice).Of these, the shell formed round vessel wall trachea and bronchi.They flattened or rounded thick elastic fibers are parallel, and many of them have ramifications.The space between them takes a loose irregular connective tissue.
Cartilage tissue
connecting cartilage cells and formed a large amount of intercellular substance.It is designed to perform a mechanical function.There are 2 types of cells that form this tissue:
- Chondrocytes having an oval shape and the core.They are found in capsules, which are spread around the intercellular substance.
- chondroblasts, which are flattened young cells.They are on the periphery of the cartilage.
cartilage Experts divide into 3 types:
- hyaline, occurring in various organs, such as ribs, joints and airways.Intercellular substance of the cartilage translucent.It has a uniform consistency.Covered with hyaline cartilage perichondrium.It has bluish-white hue.Because it is the skeleton of the fetus.
- elastic, which is the building material of the larynx, the epiglottis, the external walls of the ear canal, the cartilaginous part of the ear, the small bronchi.Its intercellular substance is developed elastic fibers.This cartilage no calcium.
- collagen, which is the basis of the intervertebral discs, menisci, the symphysis pubis, and the sternoclavicular joint.Its extracellular matrix comprises a dense fibrous connective tissue, consisting of parallel puchochkov collagen fibers.
This type of connective tissue, regardless of location in the body has the same cover.It is called the perichondrium.It is composed of dense fibrous tissue composed of collagen and elastic fibers.It has a large number of nerves and blood vessels.Cartilage is growing thanks to the transformation of the structural elements of the perichondrium.At the same time they are able to quickly transform.These structural elements are transformed into cartilage cells.This fabric has its own peculiarities.Thus, the extracellular matrix of mature cartilage has no blood vessels, therefore power is supplied by diffusion of substances from the perichondrium.This fabric is characterized by its flexibility, it is resistant to pressure and has a sufficient softness.
connective tissue connecting bones
bone is particularly hardness.This is due to calcification of its intercellular substance.The main function of the connecting bone - musculoskeletal manual.From it built all the bones of the skeleton.The main structural elements of the fabric:
- Osteocytes (bone cells), which have a complex form of process.They have a compact nucleus darker.These cells are found in bone cavities, follow the contours of osteocytes.Between them is the intercellular substance.These cells are unable to reproduce.
- osteoblasts are the building blocks of bone.They have a rounded shape.Some of them have multiple cores.Osteoblasts are the periosteum.
- Osteoclasts, which are large multinucleated cells involved in the destruction of calcified bone and cartilage.Throughout a person's life changes the structure of the tissue.At the same time the process of disintegration carried the formation of new elements, resulting in the destruction of the site and in the periosteum.In this complex involved the replacement of cells, osteoclasts and osteoblasts.
Bone tissue contains intercellular substance consisting of primary amorphous.There are osseinovye fiber that are not found in other organs.It is the connective tissue fabric:
- coarse-fibered, presented in embryos;
- plate, available in children and adults.
This type of fabric consists of a structural unit as a bone plate.It is produced by cells located in special capsules.Between them there is a fine-fibered intercellular substance, which contains calcium salts.Osseinovye fibers having a considerable thickness, in the bone plate foredeck parallel to each other.They lie in a certain direction.In the neighboring bone plates fibers are perpendicular to the direction of the other elements.This ensures high strength of this tissue.
bony plates located in different parts of the body are arranged in a certain order.They are the building blocks of flat, tubular and mixed bones.In each of these records are the basis for complex systems.For example, the tubular bone consists of three layers:
- Outdoor, which on the surface of the plate overlap next data layer structural units.However, they do not form a complete ring.
- Middle formed osteons in which the bone plates are formed around the blood vessels.However, they are arranged concentrically.
- house, in which a layer of bony plates restricts the space where the bone marrow.
