Regeneration. Physiological regeneration, its significance. What is regeneration

Ticket No. 53 Regeneration as a process of maintaining the integrity of biological systems. Physiological regeneration, its meaning. Phases, mechanisms of regulation. The importance of regeneration for biology and medicine.

Ticket number 52 The concept of homeostasis. General patterns of homeostasis in living systems. Genetic, cellular and systemic basis of homeostatic reactions of the body. The role of the endocrine and nervous systems in ensuring homeostasis and adaptive reactions.

HOMEOSTASIS is the property of a living organism to maintain relative dynamic constancy internal environment. Homeostasis is expressed in relative constancy chemical composition, osmotic pressure, stability of the main physiological functions. Homeostasis is specific and determined by genotype.

GENERAL REGULARITIES OF HOMEOSTASIS

1. The ability to maintain homeostasis is a property of a living system that is in a state of dynamic equilibrium with environmental conditions.

2. The molecular genetic level of homeostasis is ensured by the processes of DNA replication and repair at the cellular level - compensatory restoration of a number of organelles with increased function.

3. Control over genetic constancy is carried out by the immune system.

4. In the systemic mechanisms of homeostasis, cybernetic principles of negative feedback: with any disturbing influence - the influence of nervous and endocrine mechanisms.

5. Normalization physiological indicators carried out on the basis of the property of irritability, in higher organisms- instincts, conditioned reflexes, elements of rational activity, abstract thinking.

6. Each age period is characterized specific features metabolism, energy, homeostasis mechanisms:

Juvenile period - homeostasis mechanisms have not matured - disruption physiological processes, disease processes;

Mature - improvement metabolic processes. The homeostasis restoration system provides compensation;

Senile - the reliability of the mechanism for maintaining homeostasis is weakened.

7. The body’s adaptive reactions to environmental conditions are aimed at maintaining homeostasis

8. Biorhythms - rhythmic processes of life.

endocrine system coordinates and regulates the activity of almost all organs and systems of the body, ensures its adaptation to constantly changing conditions of the external and internal environment, maintaining the constancy of the internal environment necessary to maintain the normal functioning of a given individual. The secretion of some hormones, such as thyroxine, is very tightly regulated. However, the concentrations of most other hormones can vary widely to maintain the constancy of a number of physiological parameters with continuous changes in the immediate needs of the body. For example, the secretion rates of insulin and glucagon fluctuate greatly to keep blood glucose concentrations within acceptable limits. Changes in aldosterone (see Table 4.1 above) and vasopressin levels reflect the need to maintain a constant blood volume by regulating water-salt balance. Concentrations of epinephrine and norepinephrine depend on the degree of general activity of the body and may vary in different local vascular networks. This allows them to regulate the strength and frequency of heart contractions, and selectively act on blood vessels to ensure blood flow to specific organ systems according to need.

Especially important has a constancy of the internal environment for the activities of the central nervous system: even minor chemical and physicochemical changes occurring in the cerebrospinal fluid, glia and pericellular spaces can cause sharp violation the course of life processes in individual neurons or in their ensembles. A complex homeostatic system, including various neurohumoral, biochemical, hemodynamic and other regulatory mechanisms, is the system for ensuring the optimal level blood pressure. Wherein upper limit blood pressure level is determined by the functionality of baroreceptors vascular system body, and the lower limit is the body's needs for blood supply.

Regeneration- the process of the body restoring lost or damaged structures. Regeneration maintains the structure and functions of the body, its integrity. There are: physiological, reparative and pathological

Physiological regeneration- restoration of organs, tissues, cells or intracellular structures after their destruction during the life of the body.

Reparative regeneration

Physiological regeneration is a process of updating the functioning structures of the body. Structural homeostasis is maintained, ensuring the ability of organs to constantly perform their functions. Is a manifestation of the properties of life, like self-renewal (renewal of the epidermis of the skin, epithelium of the intestinal mucosa). There are two phases in physiological regeneration: destructive and restorative. It is believed that the breakdown products of some cells stimulate the proliferation of others. Hormones play a major role in the regulation of cellular renewal. Physiological regeneration is inherent in organisms of all species, but it occurs especially intensively in warm-blooded vertebrates, since they generally have a very high intensity of functioning of all organs compared to other animals.

This process is allotted great value in the restoration of damaged tissues and organs (the phenomenon of restorative regeneration). In other words, without regeneration, healing is impossible.

The meaning of regeneration in biology is, first of all, an integral process of tissue renewal; cells that are aging and are not capable of normal functioning and maintaining higher biological levels are renewed. This is the process of regeneration.

Ticket No. 54 Reparative regeneration. Methods; mechanisms (molecular genetic, cellular and systemic). Regulation of regeneration. Features of recovery processes in humans.

Reparative regeneration- restoration of structures after injury or other damaging factors. During regeneration, processes such as determination, differentiation, growth, integration, etc. occur, similar to the processes that take place in embryonic development.

There are several methods (varieties) of reparative regeneration. These include epimorphosis, morphallaxis, hypertrophy. Hypertrophy and hyperplasia of cells of organs and tissues, as well as the occurrence and growth of tumors overgrowth and proliferation of cells, tissues and organs.

Hypertrophy is an increase in the size of an organ or tissue due to an increase in the size of each cell, a weakening of function, and ultimately, when the adaptive mechanisms are exhausted, decompensation of the organ occurs.

In animals, there are two main methods of regeneration: epimorphosis and morphallaxis.

Epimorphosis consists of the growth of a new organ from the amputated surface. In epimorphic regeneration, the lost body part is restored due to the activity of undifferentiated embryonic-like cells. Regeneration by blastema formation is widespread in invertebrates and also plays an important role in the regeneration of amphibian organs.

Morphallaxis is regeneration by restructuring the regenerating site. With morphallaxis, other tissues of the body or organ are transformed into the structures of the missing part. In hydroid polyps, regeneration occurs mainly through morphallaxis, while in planaria, both epimorphosis and morphallaxis occur simultaneously.

Numerous factors of endo- and exogenous nature are involved in the regulation of regeneration processes. The influence of hormones has been the most studied. Regulation of cell mitotic activity various organs carried out by hormones of the adrenal cortex, thyroid gland, gonads, etc.

Ticket No. 55 Population gene pool; genetic heterogeneity; genetic unity, dynamic balance. Allele and genotype frequencies. Hardy-Weinberg law.

The gene pool of a population is the totality of all genes in a population

Genetic heterogeneity is a collection various types genes

Genetic unity is a set of genes characteristic of a given population, traceable in each organism included in its composition.

The tendency of populations to maintain internal stability through their own regulatory mechanisms is called homeostasis, and fluctuations in population numbers within a certain average size- their dynamic balance. The ability of a population or system of organisms to maintain stable dynamic equilibrium under environmental conditions that change is called homeostasis.

Regeneration is the process of formation of new tissue in place of dead or dead tissue. In normal healthy body physiological cell regeneration occurs all the time, the dead stratum corneum of the epidermis is constantly peeled off; instead, new cells multiply in inner layer skin. Similar desquamation cover epithelium It also happens on mucous membranes.

Time factor

Red blood cells in blood vessels typically live between sixty and one hundred and twenty days. Thus, within approximately two months, their complete renewal occurs. Leukocytes and other blood cells are also systematically replenished as they die or die.

In various pathological processes, cells and tissues can be destroyed in more than normal.

This process is of great importance in the restoration of damaged tissues and organs (the phenomenon of restorative regeneration). In other words, without regeneration, healing is impossible.

What is the regenerative process

The term " regenerative process“It is customary to call the restoration of destroyed tissue during inflammation and after its completion. In case of proliferation (inflammation), new cells are formed. The formation of granulation tissue during inflammation and especially at the very end is called regeneration connective tissue.

How does bone tissue regenerate?

The bone heals after a fracture also thanks to the regeneration of bone tissue. The newly formed tissue grows and is larger in size than the dead tissue; because of this, the granulation tissue extends beyond the boundaries of the former inflammatory area and protrudes from wound surface. So when bones heal, more bone tissue forms at the fracture site than was present before the fracture occurred. Therefore, in this place the bone is thicker, and the formation of a bone callus is diagnosed.

The more complex the structure of the tissue, the more differentiated its function, the less its ability to regenerate. Recovery muscle tissue possible within very limited limits. The most difficult thing is the restoration of striated muscles.

Previously, it was suggested that nervous tissue, which consists of nerve cells, should be considered the most complex in its structure. Experts believed that after the death nerve cells absolutely not restored. But it has now been established that regenerative processes are also possible in these tissues.

What does regeneration depend on?

The implementation of recovery processes largely depends on the stability and age of the body. In a healthy, young, strong person recovery process proceeds more successfully than in the weakened and old.

regeneration

Regeneration (in pathology) is the restoration of the integrity of tissues damaged by any painful process or external traumatic influence. Recovery occurs due to the proliferation of neighboring cells, filling the defect with young cells and their subsequent transformation into mature tissue. This form is called reparative (compensatory) regeneration. In this case, two options for regeneration are possible: 1) the loss is compensated by tissue of the same type as the one that died (complete regeneration); 2) the loss is replaced by young connective (granulation) tissue, which turns into scar tissue (incomplete regeneration), which is not regeneration in the proper sense, but the healing of a tissue defect.

Regeneration is preceded by the release of this area from dead cells by enzymatic melting and absorption into the lymph or blood or by phagocytosis (see). Melting products are one of the stimulators of the proliferation of neighboring cells. In many organs and systems there are areas whose cells are a source of cell proliferation during regeneration. For example, in skeletal system such a source is the periosteum, the cells of which, when multiplying, first form osteoid tissue, which later turns into bone; in the mucous membranes - cells of deep-lying glands (crypts). Regeneration of blood cells occurs in the bone marrow and outside it in the system of reticular tissue and its derivatives ( lymph nodes, spleen).

Not all tissues have the ability to regenerate, and not to the same extent. Thus, the muscle cells of the heart are not capable of reproduction, culminating in the formation of mature muscle fibers, therefore, any defect in the myocardial muscles is replaced by a scar (in particular, after a heart attack). When brain tissue dies (after hemorrhage, arteriosclerotic softening), the defect is not replaced nerve tissue, and a kyota is formed.

Sometimes the tissue that appears during regeneration differs in structure from the original (atypical regeneration) or its volume exceeds the volume of dead tissue (hyperregeneration). This course of the regeneration process can lead to tumor growth.

Regeneration (Latin regenerate - revival, restoration) - restoration of the anatomical integrity of an organ or tissue after the death of structural elements.

IN physiological conditions regeneration processes occur continuously with varying intensity in different organs and tissues, according to the intensity of the survival of the cellular elements of a given organ or tissue and their replacement with newly formed ones. Formed elements of blood, cells of the integumentary epithelium of the skin, mucous membranes of the gastrointestinal tract, respiratory tract. Cyclic processes in the female reproductive system lead to rhythmic rejection and renewal of the endometrium through its regeneration.

All these processes are the physiological prototype of pathological regeneration (it is also called reparative). Features of the development, course and outcome of reparative regeneration are determined by the extent of tissue death and the nature of pathogenic influences. The last circumstance must be especially borne in mind, since the conditions and causes of tissue death are essential for the regeneration process and its outcomes. For example, scars after skin burns have a special character, different from scars of other origins; syphilitic scars are rough, lead to deep retractions and disfigurement of the organ, etc. d. Unlike physiological regeneration, reparative regeneration covers wide circle processes leading to compensation of the defect caused by the loss of tissue due to its damage. A distinction is made between complete reparative regeneration - restitution (replacement of the defect with tissue of the same type and the same structure as the dead one) and incomplete reparative regeneration (filling the defect with tissue that has greater plastic properties than the dead one, i.e. ordinary granulation tissue and connective tissue with further turning it into scar tissue). Thus, in pathology, regeneration often means healing.

The concept of regeneration is also associated with the concept of organization, since both processes are based on the general laws of new tissue formation and the concept of substitution, i.e. displacement and replacement of pre-existing tissue by newly formed tissue (for example, substitution of a blood clot with fibrous tissue).

The degree of completeness of regeneration is determined by two main factors: 1) the regenerative potential of a given tissue; 2) the volume of the defect and the same or heterogeneous species of dead tissue.

The first factor is often associated with the degree of differentiation of a given tissue. However, the very concept of differentiation and the content of this concept are very relative, and comparison of tissues on this basis with the establishment of a quantitative gradation of differentiation in functional and morphological terms is impossible. Along with tissues that have a high regenerative potential (for example, liver tissue, mucous membranes of the gastrointestinal tract, hematopoietic organs, etc.), there are organs with negligible potential for regeneration, in which regeneration is never completed full restoration lost tissue (eg, myocardium, central nervous system). Connective tissue, wall elements of the smallest blood vessels and lymphatic vessels, peripheral nerves, reticular tissue and its derivatives. Therefore, plastic irritation, which is trauma in the broad sense of the word (that is, all its forms), first and foremost stimulates the growth of these tissues.

The volume of dead tissue is essential for the completeness of regeneration, and the quantitative limits of tissue loss for each organ, which determine the degree of restoration, are more or less known empirically. It is believed that for the completeness of regeneration, not only volume as a purely quantitative category is important, but also the complex diversity of dead tissues (this especially applies to tissue death caused by toxic-infectious influences). To explain this fact, one should apparently turn to general patterns stimulation of plastic processes in pathological conditions: the stimulators are the products of tissue death themselves (hypothetical “necrohormones”, “mitogenetic rays”, “trephons”, etc.). Some of them are specific stimulators for cells of a certain type, others are nonspecific, stimulating the most plastic tissues. Nonspecific stimulants include products of the breakdown and vital activity of leukocytes. Their presence during reactive inflammation, which always develops with the death of not only parenchymal elements, but also the vascular stroma, promotes the proliferation of the most plastic elements - connective tissue, i.e., the eventual development of a scar.

Exists general scheme sequence of regeneration processes regardless of the area where it occurs. In pathological conditions, regeneration processes in the narrow sense of the word and healing processes have different character. This difference is determined by the nature of tissue death and the selective direction of action of the pathogenic factor. Pure forms of regeneration, i.e. restoration of tissue identical to the lost one, are observed in cases where, under the influence pathogenic effects Only specific parenchymal elements of the organ die, provided they have a high regenerative potency. An example of this is the regeneration of renal tubular epithelium that has been selectively damaged by toxic exposure; regeneration of the epithelium of the mucous membranes during desquamation; regeneration of lung alveolocytes in desquamative catarrh; regeneration of skin epithelium; endothelial regeneration blood vessels and endocardium, etc. In these cases, the source of regeneration is the remaining cellular elements, the reproduction, maturation and differentiation of which leads to complete replacement of the lost parenchymal elements. When complex structural complexes die, restoration of lost tissue occurs from special areas of the organ, which are unique regeneration centers. In the intestinal mucosa, in the endometrium, such centers are glandular crypts. Their multiplying cells cover the defect first with one layer of undifferentiated cells, from which glands then differentiate and the structure of the mucosa is restored. In the skeletal system, such a regeneration center is the periosteum, in the integumentary squamous epithelium - the Malpighian layer, in the blood system - bone marrow and extramedullary derivatives of reticular tissue.

The general law of regeneration is the law of development, according to which, in the process of neoplasm, young undifferentiated cellular derivatives arise, which subsequently undergo stages of morphological and functional differentiation up to the formation of mature tissue.

The death of areas of an organ consisting of a complex of various tissues causes reactive inflammation (see) along the periphery. This is an adaptive act, since the inflammatory reaction is accompanied by hyperemia and increased tissue metabolism, which promotes the growth of newly formed cells. In addition, inflammatory cellular elements from the group of histophagocytes are plastic material for the formation of connective tissue.

In pathology, anatomical healing is often achieved with the help of granulation tissue (see) - the stage of new formation of a fibrous scar. Granulation tissue develops during almost any reparative regeneration, but the degree of its development and final outcomes vary within very wide limits. Sometimes it is difficult to distinguish when microscopic examination tender areas of fibrous tissue, sometimes coarse dense strands of hyalinized bradytrophic scar tissue, often subject to calcification (see) and ossification.

In addition to the regenerative potential of a given tissue, the nature of its damage, its volume, general factors are important in the regeneration process. These include the age of the subject, the nature and characteristics of nutrition, and the general reactivity of the body. In case of innervation disorders or vitamin deficiencies, the usual course of reparative regeneration is distorted, which is most often expressed in a slowdown in the regeneration process and sluggishness of cellular reactions. There is also the concept of fibroplastic diathesis as a constitutional feature of the body to respond to various pathogenic irritations with increased formation of fibrous tissue, which is manifested by the formation of keloid (see), adhesive disease. IN clinical practice it is important to consider general factors to create optimal conditions completeness of the regeneration process and healing.

Regeneration is one of the most important adaptive processes that ensure the restoration of health and continuation of life under emergency circumstances created by the disease. However, like any adaptive process, regeneration at a certain stage and along certain paths of development can lose its adaptive significance and itself create new forms of pathology. Disfiguring scars that deform an organ and sharply disrupt its function (for example, cicatricial transformation of heart valves as a result of endocarditis) often create severe chronic pathology, requiring special therapeutic measures. Sometimes the newly formed tissue quantitatively exceeds the volume of the dead tissue (super-regeneration). In addition, in every regenerate there are elements of atypia, the sharp severity of which is a stage of tumor development (see). Regeneration individual organs and tissues - see the relevant articles on organs and tissues.

Regeneration

Regeneration(restoration) - the ability of living organisms to restore damaged tissues, and sometimes entire lost organs, over time. Regeneration is also called the restoration of a whole organism from its artificially separated fragment (for example, the restoration of a hydra from a small fragment of the body or dissociated cells). In protists, regeneration can manifest itself in the restoration of lost organelles or cell parts.

Regeneration is the restoration by the body of lost parts at one or another stage of the life cycle. Regeneration that occurs in the event of damage or loss of any organ or part of the body is called reparative. Regeneration in the process of normal functioning of the body, usually not associated with damage or loss, is called physiological.

Physiological regeneration

In every organism, throughout its life, processes of restoration and renewal constantly occur. In humans, for example, the outer layer of skin is constantly renewed. Birds periodically shed their feathers and grow new ones, and mammals change their fur. Deciduous trees lose leaves every year and are replaced with fresh ones. Such processes are called physiological regeneration.

Reparative regeneration

Reparative is the regeneration that occurs after damage or loss of any part of the body. There are typical and atypical reparative regeneration.

In typical regeneration, the lost part is replaced by the development of exactly the same part. The reason for the loss may be external influence(for example, amputation), or the animal deliberately tears off part of its body (autotomy), like a lizard breaking off part of its tail to escape from an enemy.

With atypical regeneration, the lost part is replaced by a structure that differs from the original quantitatively or qualitatively. The regenerated limb of a tadpole may have fewer toes than the original one, and a shrimp may grow an antenna instead of an amputated eye.

Regeneration in animals

Chameleon

The ability to regenerate is widespread among animals. Lower animals, as a rule, are more often capable of regeneration than more complex, highly organized forms. Thus, among invertebrates there are many more species capable of restoring lost organs than among vertebrates, but only in some of them is it possible to regenerate an entire individual from a small fragment. Nevertheless general rule the decrease in the ability to regenerate with increasing complexity of the organism cannot be considered absolute. Such primitive animals as roundworms and rotifers are practically incapable of regeneration, but in much more complex crustaceans and amphibians this ability is well expressed; Other exceptions are known. Some relatively closely related animals differ greatly in this respect. Thus, in many species of earthworms, only a new individual can completely regenerate from the front half of the body, while leeches are not able to restore even individual lost organs. In tailed amphibians, a new limb is formed in place of the amputated limb, but in the frog, the stump simply heals and no new growth occurs. There is also no clear connection between the nature of embryonic development and the ability to regenerate. Thus, in some animals with strictly determined development (comb jellies, polychaetes) in adulthood, regeneration is well developed (in crawling ctenophores and some polychaetes, a whole individual can recover from small area bodies), and in some animals with regulatory development (sea urchins, mammals) - quite weakly.

Many invertebrates are capable of regenerating large parts of their body. Most species of sponges, hydroid polyps, many species of flatworms, tapeworms and annelids, bryozoans, echinoderms and tunicates can regenerate from a small fragment of the body whole organism. Particularly noteworthy is the ability to regenerate in sponges. If the body of an adult sponge is pressed through mesh fabric, then all the cells will separate from each other, as if sifted through a sieve. If you then place all these individual cells in water and carefully, thoroughly mix, completely destroying all the connections between them, then after some time they begin to gradually come closer together and reunite, forming a whole sponge, similar to the previous one. This involves a kind of “recognition” at the cellular level, as evidenced by the following experiment: three different types of sponges were divided into individual cells in the described manner and mixed thoroughly. At the same time, it was discovered that the cells of each species are able to “recognize” the cells of their own species in the total mass and reunite only with them, so that as a result, not one, but three new sponges were formed, similar to the original three. Of other animals, only hydra is capable of restoring a whole organism from a suspension of cells.

Regeneration in humans

In humans, the epidermis regenerates well; its derivatives, such as hair and nails, are also capable of regeneration. Also has the ability to regenerate bone(bones heal after fractures). With the loss of part of the liver (up to 75%), the remaining fragments begin to rapidly divide and restore the original size of the organ. Under certain conditions, fingertips can regenerate. In connection with the detection of weak electrical voltages on regenerating tissues, it can be assumed that weak electrophoresis currents accelerate regeneration.

Notes

Literature

Dolmatov I. Yu., Mashanov V. S. Regeneration in holothurians. - Vladivostok: Dalnauka, 2007. - 208 p.
Tanaka E.M. Cell differentiation and cell fate during urodele tail and limb regeneration. Curr Opin Genet Dev. 2003 Oct;13(5):497-501. PMID 14550415
Nye HL, Cameron JA, Chernoff EA, Stocum DL. Regeneration of the urodele limb: a review. Dev Dyn. 2003 Feb;226(2):280-94. PMID 12557206
Gardiner DM, Blumberg B, Komine Y, Bryant SV. Regulation of HoxA expression in developing and regenerating axolotl limbs. Development. 1995 Jun;121(6):1731-41. PMID 7600989
Putta S, Smith JJ, Walker JA, Rondet M, Weisrock DW, Monaghan J, Samuels AK, Kump K, King DC, Maness NJ, Habermann B, Tanaka E, Bryant SV, Gardiner DM, Parichy DM, Voss SR, From biomedicine to natural history research: EST resources for ambystomatid salamanders. BMC Genomics. 2004 Aug 13;5(1):54. PMID 15310388
Andrews, Wyatt. Medicine's Cutting Edge: Re-Growing Organs, Sunday Morning, CBS News(March 23, 2008).

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Synonyms:

Proverb
Galkin, Alexander Abramovich

See what “Regeneration” is in other dictionaries:

REGENERATION- REGENERATION, the process of formation of a new organ or tissue in place of a part of the body that was removed in one way or another. Very often R. is defined as the process of restoring what has been lost, that is, the formation of an organ similar to the removed one. This... ... Great Medical Encyclopedia

REGENERATION- (late lat., from lat. re again, again, and genus, eris genus, generation). Revival, renewal, restoration of what was destroyed. In a figurative sense: a change for the better. Dictionary foreign words, included in the Russian language.... ... Dictionary of foreign words of the Russian language

REGENERATION- REGENERATION, in biology, the body’s ability to replace one of the lost parts. The term regeneration also refers to a form of Asexual Reproduction in which a new individual arises from a separated part of the mother's body... Scientific and technical encyclopedic dictionary

regeneration- restoration, recovery; compensation, regeneration, renewal, heteromorphosis, pettencoferation, revival, morphallaxis Dictionary of Russian synonyms. regeneration noun, number of synonyms: 11 compensation (20) ... Synonym dictionary

Regeneration- 1) restoration, using certain physicochemical processes, of the original composition and properties of waste products for their reuse. In military affairs, air regeneration has become widespread (especially on underwater... ... Marine Dictionary

Regeneration- – returning the used product to its original properties. [ Terminological dictionary on concrete and reinforced concrete. FSUE "Research Center "Construction" NIIZHB named after. A. A. Gvozdeva, Moscow, 2007, 110 pp.] Regeneration - restoration of waste... ... Encyclopedia of terms, definitions and explanations of building materials

REGENERATION- (1) restoration of the original properties and composition of waste materials (water, air, oils, rubber, etc.) for their reuse. It is carried out with the help of certain physical chem. processes in special regenerator devices. Wide... ... Big Polytechnic Encyclopedia

REGENERATION- (from Late Lat. regeneratio rebirth renewal), in biology, the restoration by the body of lost or damaged organs and tissues, as well as the restoration of the whole organism from its part. Mostly characteristic of plants and invertebrates... ...

REGENERATION- in technology, 1) returning the spent product to its original qualities, for example. restoration of the properties of spent molding sand in foundries, purification of used lubricating oil, transformation of worn rubber products into plastic... ... Big Encyclopedic Dictionary

28Apr

What is Cell Regeneration

Cell regeneration is the act of renewal, growth or repair of cells involved in wound healing, tissue repair and similar biological functions. This biological feature is inherent in all living organisms, from bacteria to plants and from amphibians to mammals.

In humans, unfortunately, cellular regeneration has limited opportunities compared to some representatives of life on our planet. For example, representatives of extreme regeneration can be:

Starfish and lizards are able to regrow broken or severed limbs.
Flatworms can completely clone their entire body structure for the purpose of reproduction.

Cell regeneration as a process of reproduction.

Although all organisms, including bacteria, fungi and yeast, have the biological ability to regenerate cells, this process manifests itself differently in each individual organism. Maintaining the biological integrity of the body is the main goal cellular regeneration. Some organisms also use cell regeneration as a form of asexual reproduction. For example, yeast reproduces through an asexual process of cell regeneration known as budding. The new cell grows as a separate piece attached to the old cell. It collects DNA information to produce an exact copy of the cell. After reaching maturity, the new cell separates and becomes independent of the host cell, allowing yeast and similar fungi to reproduce and grow.

Complex regeneration.

Some reptiles and amphibians have the ability to undergo complex cellular regeneration. This feature allows tissue structures to recover from damage through a process known as autotomy.

When injury occurs or such creatures are in danger, adult cells in tails, fins and other appendages can detach from the main body, leaving the appendage behind. As part of a natural biochemical process, cells at the edges of such lesions morph back into stem cells. This allows the cell regeneration process to grow a new appendage to replace the lost one.

Cell regeneration in humans.

In humans, cell regeneration is a slightly different process. Stem cells, like building blocks, allow the embryo to form organs, tissues and appendages, only in the process of formation. Once the cells develop, they cannot revert back to stem cells, as is seen in some reptiles and amphibians.

Daily on human body Billions of cells die due to necrosis or apoptosis.

Apoptosis is a form of programmed cell death that allows cells to fragment or otherwise die as part of the normal biochemical process associated with development, growth and aging. Without some form of cell regeneration, necrosis and apoptosis will eventually lead to the destruction of entire organs and tissues. But through cellular regeneration, our body grows new cells to replace dead ones.