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Galvanization is a physiotherapeutic method of electrotherapy, which uses a continuous direct electric current of low intensity (up to 50 mA) and low voltage (30-80V).
Human tissues contain both colloids (proteins, glycogen and other large molecular substances) and salt solutions. They are part of muscles, glandular tissue, as well as body fluids (blood, lymph, intercellular fluid, etc.). Molecules of substances forming them decompose into electrically charged ions: water (to a small extent) into a positively charged hydrogen ion and a negatively charged hydroxyl ion, and inorganic salts into metal ions and acidic residues, respectively. Positively charged ions move toward the cathode (negative electrode) and are called cations; negatively charged ions move toward the anode (positive electrode) and are called anions. The movement of electric current in the human body is indirect and depends on the structural, anatomical relationship between good current conductors (sheaths of nerve trunks, blood vessels, muscles) and bad ones - dielectrics (fatty tissue). When the galvanic current passes through the body tissues, complex physical and chemical processes occur in them, causing the development of a number of biological effects, both therapeutic and side effects. Under the electrodes there is a chemical process associated with the passage of electric current through the electrolytes, which is called electrolysis. As a result, positively charged ions (cations) are directed toward the cathode and negatively charged ions (anions) are directed toward the anode. When they reach the electrodes, they lose their charge and become electrically neutral atoms, which have a high chemical activity. Interacting with the solvent, they form secondary products of electrolysis - acids and alkalis, which have a strong irritating effect on the skin, up to and including burns. To avoid this, hydrophilic pads are used which are placed between the plates of metal electrodes and the skin surface. Aggressive electrolysis products accumulate at the boundary of the pad layer adjacent to the electrode directly, i.e. far from the skin surface.
The movement of ions in galvanization (scheme).
The difference in the mobility of ions is important. The univalent ions (Na and K') are smaller compared to the bivalent ions (Ca and Mg) and therefore have greater mobility. They more easily reach the surface of the corresponding electrode, the cathode. Due to the departure of these more mobile ions to the cathode, the relative concentration of Ca and Mg increases in the area of the anode. It is known that K+ and Na increase cell excitability, while Ca and Mg decrease it. Therefore, tissue excitability increases in the area of the cathode and decreases in the area of the anode, which is important for therapeutic practice. Intercellular partitions on the way of electric current passage create a certain obstacle for ions movement. Ions accumulate near the partitions and form intermediate poles in the tissue thickness, between which additional currents, called "polarization currents", arise. The latter ones increase resistance to galvanic current passage in body tissues. Thus, the biological effect of constant galvanic current is based on physical processes of electrolysis, changes in concentration of ions in cells and tissues and polarization processes. They cause irritation of nerve receptors and occurrence of reflex reactions of local and general character. Local reactions are manifested by changes in cell hydration, dispersion of protoplasm colloids, permeability of cell membranes, acceleration of blood flow, increased permeability of vascular walls. Sensitivity of peripheral nerve receptors to changes of internal environment in tissues increases. Biologically active substances (serotonin, histamine, etc.) are formed in the place of current exposure, which are absorbed into blood and determine the general reaction of the organism. Nerve impulses arising from irritation of I peripheral receptors are transmitted to CNS and cause complex responses of organs and body systems. These reactions are especially pronounced in the organs having segmental connection with the irritated area of the skin surface. Thus, galvanization of pansy area through lumbosacral vegetative apparatus has reflex influence on organs of small pelvis. In development of the response reactions, the current strength, exposure duration, polarity of the active electrode, as well as the initial functional state of the organs and systems of the organism play a significant role. Galvanic current has normalizing effect on functional state of central and vegetative nervous system, improves blood and lymph circulation, expands coronary vessels, increases heart functional capabilities, increases oxygen tension, glycogen and adenosine triphosphoric acid content in myocardium, stimulates internal secretion glands function, affects excitability of neuromuscular apparatus.
Galvanization and electrophoresis machine
Indications for the appointment of galvanization:
List of references used:
1. General physiotherapy (textbook). Authors: D.R. Rakita, O.M. Uryasiev, A.K. Ushmarov.
2. Physiotherapy and physioprophylaxis (textbook). Authors: Safronenko V.A., Gasanov M.Z. Under the general editorship of Professor Chesnikova A.I.
3. Physiotherapy. Authors: L.M. Kliachkin, M. N. Vinogradova.
The literature on this topic you can download from our site in the appropriate section: Literature. Physiotherapy.