Tumor [tumors; synonym: neoplasms (neoplasmata), blastoma (blastomata)] - redundant which continued after termination of the underlying reasons, not coordinated with the body's abnormal growth of tissue consisting of qualitatively changed cells, which became atypical respect to differentiation and nature of growth and transferring these properties to its derivative. A malignant tumor is a tumor with infiltrative destructive character growth and significant anaplasia (see). N. N. Petrov was named Acting "irregular excess focal cell reproduction.
A number of characteristics that define the essence of O. So, they occur in isolated foci of the tissues of the body, but differ from the latter by your growth and low differentiation (cellular atypia, anaplasia or metaplasia) their constituent cells. Briefly, we can say that the Acting is "plus a multiplication of cells, minus their differentiation". This properties are passed to the offspring of tumor cells. Tumor growth is excessive, relatively independent of the body - "offline". Malignant Acting during its growth can investirovat, to grow, to destroy surrounding tissue. Unlike various swelling and "false" Oh caused by inflammation, or disorders of blood circulation, true Acting increase at the expense of reproduction own cells, but not at the expense of exudation and migration connective tissue cellular elements. Another important feature of tumor growth, distinguishing it from regenerative, - the inadequacy of the extent of the tissue damage that from the beginning, he pathological, not a physiological process. When removing part of O. she is again growing, recurs, but does not participate in regeneration, construction of the normal tissues of the body. However tumor growth, as any pathological process, has its physiological prototype, which is manifested in the growths of cells and tissues caused by hormonal influences (for example, the introduction of chorion villus in the tissue of the uterus during pregnancy). In the latter case one can speak about the physiological prototype infiltrative and even destructive growth.
The occurrence of tumors in one way or another organ or tissue begins with the appearance of a small group changed and continues to change cells. Development O. occurs gradually. There are distinguished several stages - uneven diffuse hyperplasia, focal proliferation, the formation of the so-called benign O. finally, possible malignancy as these last and focal proliferation. Expansion immediately preceding malignant O. and in her passing, called precancer (see), and earlier tissue changes can be considered precancerous. Further development of Acting depends on the organism as a whole and may occur, apparently, only for violation of certain correlation. This is evidenced by the duration of the development O. the person and the possibility of metastasis many years after the removal of the primary tumor (so-called "dormant metastases"). However, despite the undoubted importance in the Genesis O. changes of the organism as a whole, we must not forget that each Acting begins with local focal growths that tumor cells that have acquired new pathological properties, pass them on to their descendants, and that this creates a new breed of cells, what is the essence of the pathological process and the basis of the disease.

Tumor (synonym: neoplasms, blastoma, tumors) are excessive tissue excrescence, which continued after termination of the underlying reasons. This growth is not coordinated with the body - it offline. Grow cells, which became atypical respect to differentiation and nature of growth and transferring these properties to their descendants.
Clinical and morphological point of view distinguish between benign and malignant tumors.
Criterion is the nature of their growth. Benign O. grow slowly, only pushing, pushing, and sometimes compress the surrounding tissue, but without germination in them. Malignant tumors differ infiltrative growth - they germinate in surrounding tissue and destroy them. Hence, the possibility of metastasizing tumors (see Metastasis), characteristic of malignant tumors. At destruction of the walls of blood vessels can reach the tumor cells that are fond of the blood or lymph, are recorded in other tissues and organs and can proliferate and form secondary, i.e. metastatic node. Benign tumors do not metastasize.
However, they can be dangerous if compress vital centers in the brain and spinal cord or respiratory or digestive path. If the operation has been removed part of benign tumor, the tumor can grow again recur.
Tumors found in animals of all classes and species - fish, amphibians, reptiles, birds, all mammals and humans.
O. consist of parenchyma and stroma. Parenchyma presents its own tissue tumors, the main component of its weight and defines its growth and character. Stroma - layer of connective tissue, in which vessels and nerves pass.
In the nomenclature of tumors reflected their tissue of origin: the end of "OMA" (from the Greek word "inkoma" the tumor) is attached to the roots of the words indicating a particular tissue. A tumor of the cartilage is called chondroma, the tumor from adipose tissue - lipoma, from the muscle - uterine and so on, Some tumors retain a special historically entrenched behind them names. A malignant tumor of connective tissue called sarcoma (see) because in the context of her cloth reminds fish meat (in Greek sarkos - meat). Malignant epitelioma is called "cancer", probably due to the fact that the first observations of ancient doctors treat breast cancer or skin that grow in surrounding tissue bands, reminding a claw of cancer. In many countries, for example France, the term "cancer" (cancer) applies to all malignant O., and in the USSR and several other countries, cancer is called only malignant epithelial tumors (see Cancer).
Pathological classification of tumors based on their varying fabric: there are epithelium, connective tissue, muscle and nerve tumors. Epithelial tumors are divided into originating from glandular epithelium and flat. If the tumor visible patterns gland, called an adenomaand a malignant - adenocarcinoma. Connective-tissue tumors depending on the type of tissue are divided into fibroids, lipoma, handsome, osteomas.
Some O. called by the authority or a certain part of, for example hepatoma - a tumor of the liver cells, insuloma - from the tissues of the pancreatic islets, etc.
Malignant tumors develop, usually from a number of previous them relatively benign growths that called precancerous (see the Precancer). Thus, there is a gradual development of tumor process, a kind of its progression. If the disease has not been promptly recognized and have not been applied due care treatment, the progression of the tumor, its metastasis, the destruction of the vital organs, the violation of life-important ways, as, for example, digestive or respiratory, anemia due to bleeding from the wounded tumor tissue, the General intoxication of the organism by decay products of tumors and disorders of metabolism,which can lead to significant depletion, called cachexia (see).

Pages: 1 2 3