Thus, phagocytosis - what is it?Let's try to understand the definition of the term.The word "phagocytosis" arose from two Greek morpheme - phagos (devouring) and kytos (cell).International medical term phagokytosis, unlike Russified is ending osis, which translates from the Greek as "process" or "event".Thus, literally, this definition refers to the process of recognition of a foreign agent specific cells, targeted traffic to it, capture and sequestration followed by cleavage.In this article we will talk about the essence of phagocytosis.We also talk about what are the phagocytes, consider the stage and find the difference between complete and incomplete phagocytosis.
history of the discovery of special motile cells
outstanding Russian scientist - II Mechnikov in 1882 - 1883.conducted experiments on intracellular digestion studying transparent larvae of starfish.Academic wondered whether to stay at the multicellular organisms the ability to capture food distinct cells.And digest it well, as do the protozoa such as amoeba.Mechnikov conducted experiments: to enter into the bodies of larvae powder carmine and watched around these small blood-red grains grew wall cells.They seized and swallowed paint.Then there was a scientist hypothesized that any organism must have a special defense cells, which can absorb and digest other particles harmful to the body.To confirm their hypothesis, the researchers used the pink spikes are introduced into the body of the larvae of the starfish.Some time later, the researchers found that the cells are surrounded by thorns, trying to counter "pests" and push them.These specific protective particles found in the body of the larvae, a scientist called phagocytes.Through this experience revealed Mechnikov phagocytosis.In 1883, he reported his discovery to the seventh congress of Russian scientists.In the future, the scientist continued to work in this direction, it has created a comparative pathology of inflammation, as well as the phagocytic theory of immunity.In 1908, together with the scientist Paul Ehrlich, he received the Nobel Prize for their important biological research.
phagocytosis phenomenon - what is it?
Mechnikov watched and learned the role of phagocytosis in the protective reactions of the human organism and in higher animals.Scientists have found that this process plays a significant role in the healing of various wounds.Biological Encyclopedic Dictionary gives the following definition.Phagocytosis is an active gripping and absorption of foreign objects such as bacteria, microfungi and cell fragments, single-celled organisms or specific cells (phagocytes), available in any multicellular organism.What is the essence of phagocytosis?It is believed that it is the oldest form of protection of a multicellular organism.The functioning of the human immune system and phagocytosis plays a crucial role.He is the first reaction to the introduction of a variety of viruses, bacteria and other foreign agents.Phagocytes constantly circulate throughout the body, searching for "pests".When a foreign agent is identified, the binding it with the receptor.Then phagocyte pest absorbs and destroys it.
two main groups motile cells - "defenders"
phagocytes are always active and ready at any time to deal with the source of infection.They have a certain autonomy, since they can carry out their functions not only inside but also outside the body: on the surface of mucous membranes in areas of damaged tissue.Phagocytes person in terms of their effectiveness, scientists are divided into two groups - the "professional" and "unprofessional."The first is the monocytes, neutrophils, macrophages, mast cells, dendritic cells and tissue.The major mobile phagocytes are white blood cells - white blood cells.They emigrated in the inflammation and implement protective functions.Phagocytosis of leukocytes involves detection, capture and destruction of foreign objects, as well as their own dead or damaged cells.After performing its functions of the white blood cells move into the bloodstream, and continues to circulate in the blood, and the other - to undergo apoptosis or dystrophic changes."Unprofessional" group consists of fibroblasts and reticular endothelial cells, which have low phagocytic activity.
phagocytosis process: the first stage
consider how the process of controlling harmful organisms.Scientists identify four stages of phagocytosis.The first is a rapprochement: phagocyte approaching foreign object.This is either due to accidental collision, or as a result of active directional movement - chemotaxis.There are two types of chemotaxis - positive (towards the phagocytes) and negative (the movement of phagocytes).Typically, positive chemotaxis carried to the site of tissue damage, and also causes the microbes and their food.
Disclaimer phagocytes to foreign agents
After rapprochement kletki "protector" with malicious particle begins the second stage.She is sticking.A macrophage reaches an object, and regards it is attached.For example, white blood cells, arrived in the inflammation and adherent to the vessel wall, not detached from it even though most of the blood flow velocity.The mechanism of adhesion is carried out by surface charge phagocyte.As a rule, it is negative, and the surface of objects phagocyte is positively charged.In this case, a maximum adhesion.Negatively charged particles, for example, tumor, are captured by phagocytes significantly worse.Nevertheless, there is adherence to such particles.It is carried out through the action of the mucopolysaccharides, existing on the surface of the membrane of phagocytes, as well as by reducing the viscosity of the cytoplasm and serum proteins enveloping foreign agent.
third stage of phagocytosis
After sticking to the foreign object phagocyte starts its absorption, which may occur in two ways.At the point of contact shell foreign object and then the object is drawn into the cell.At the same time the object merge the free edge of the membrane, and eventually formed an isolated vacuole contains within itself harmful particle.The second way of absorption - the appearance of pseudopodia envelop foreign particles and connects to them.As a result, they are enclosed in vacuoles within the cells.As a rule, with the help of pseudopodia phagocytes absorb microfungi.Retraction or envelop a malicious object is made possible thanks to the fact that the shell phagocyte endowed contractile properties.
intracellular cleavage "pest"
The fourth stage involves the intracellular phagocytosis digestion.This occurs as follows.The vacuole containing foreign particles enter the lysosomes having complex of digestive enzymes are activated and poured.This forms the environment in which the cleavage occurs easily biological macromolecules ribonuclease, amylase, protease and lipase.Due to the destruction happening activates enzymes and digestion, and then the release of the decay products of the vacuole.Now you know what the four stages of phagocytosis.Protecting the body is carried out in stages: first a convergence phagocyte and object, then attraction, that is, the location of unwanted particles on the surface of "protector", and after - the absorption and digestion of the pest.
Incomplete and complete phagocytosis.What are their differences?
Depending on what will be the result of intracellular digestion of foreign particles into two categories - complete and incomplete phagocytosis.The first completed the total destruction of the object and elimination of degradation products in the environment.Incomplete phagocytosis - what is it?The term means that the alien cells are absorbed by phagocytes remain viable.They can ruin the vacuole or to use it as "soil" for reproduction.An example of incomplete phagocytosis is the absorption of Neisseria gonorrhoeae in the body, which has no immunity to them.Incomplete phagocytosis pathogens persist in phagocytes and spread throughout the body.So, in place of the protective mechanism of phagocytosis becomes a conductor of disease, pests helping to spread and multiply.
Causes of the process of intracellular digestion
Violation of phagocytosis occurs due to defects in the formation of phagocytes, as well as the suppression of the activity of mobile kletok- "defenders".In addition, an adverse change in the intracellular digestion perhaps because of hereditary diseases such as disease and Alder Chedyaka-Higashi.Violation formation of phagocytes, including regeneration of leukocytes often occurs when radiation exposure or due to inherited neutropenia.Suppression activity of phagocytes may occur due to the deficiency of certain hormones, electrolytes and vitamins.Also glycolytic poisons and microbial toxins adversely affect the functioning of phagocytes.We hope, through this article, you will easily be able to answer the question: "phagocytosis - what is it?".Good luck!
