GENERAL PHYSIOLOGY OF EXCITABLE TISSUES

Аннотация

The excitatory system is composed mainly of nerve and muscle fibers, which respond to internal influences and the organization. Three articles consider the physiological processes in the excitatory system and their channels, the protection of ion channels, the absorption of membrane potential, the important role of nerve impulses in the recovery of the nerve impulse. The article provides an in-depth analysis of the specific features of the nerve and muscle fibers, the degree of excitability and the role of these processes in the life of the organism. help, the electrophysiological properties of the excitatory reaction, the protection of individual parts and biochemical processes through them. Keywords:Nerve, muscle, endocrine cells, membrane potential, excitation threshold, refractory period, transmitters. Excitable tissues are tissues that can generate rapid and variable electrical signals (action potentials) in response to external stimuli, and examples of such tissues include nervous tissue, muscle tissue, and some endocrine cells. Nerve cells (neurons) transmit information throughout the body by transmitting nerve impulses. Muscle cells provide movement by contracting. Some endocrine cells, such as the chromaffin cells of the adrenal gland, have the ability to be stimulated to release hormones. All cells can switch from a physiologically quiescent stateto an excited state in response to stimuli. However, the term "excitable tissue" is used specifically only for nervous, muscular, and glandular tissues, since in these tissues excitation occurs with the occurrence of an electrical impulse that propagates along the cell membrane. Excitability is understood as the ability of a living cell to respond to given stimuli with excitation. Excitation is manifested by the response of tissues to given stimuli with specific (transmission of impulses through nervous tissue, muscle contraction, secretion of secretions by glands) and general reactions (generation ofaction potentials, metabolicchanges). Themain characteristics ofexcitabletissues are as follows: Membrane potential The membrane potential of excitable cells is present at rest due to the uneven distribution of ions in the membranes. Normally, the interior of the cell is negatively charged relative to the exterior (-70 mV to -90 mV), and this potential is maintained by the selectivepermeability ofion channels and theactivity of ionpumps (e.g., theNa+/K+ pump). Ion channels are protein channels located in the membrane that allow the movement of specific ions (Na+, K+, Ca2+, Cl-) across the membrane. Ion channels can have a "gating" page516 INTERNATIONAL JOURNAL OF ARTIFICIAL INTELLIGENCE ISSN:2692-5206,ImpactFactor:12,23 AmericanAcademicpublishers,volume05,issue04,2025 Journal: https://www.academicpublishers.org/journals/index.php/ijai mechanism, meaning they open or close in response to a specific signal (e.g., a change in membranepotential, ligand binding). Action potential An action potential is generated when the membrane potential reaches a certain threshold. This is a rapid and short-term change in membrane potential that leads to the transmissionofnerve impulses and musclecontraction and consists ofthefollowing stages. a)Depolarization b)Repolarization c)Hyperpolarization Whenthe membrane potentialreaches acertain threshold, an action potential is generated. The threshold of excitation is the minimum level of depolarization that the membrane potential must reach to generate an action potential; if the stimulation does not reach the threshold ofexcitation,noaction potential is generated. Refractory period After the generation of an action potential, the cell is unable to respond to new stimulation for a certain period of time. This period is called the refractory period and is divided into two phases: the absolute refractory period and the relative refractory period. During the absolute refractory period, the cell cannot respond to any stimulation. During the relativerefractory period, thecell canrespond toa stronger stimulation. The specific properties of nervous and muscular tissues, their degree of excitability, and the roleofthese processes in thelifeofthe organism. Nervous tissue consistsof neurons and glial cells. Neurons are thebasic functional unitsand are specialized for receiving, processing, and transmittingimpulses. Glial cells support, nourish, and protect neurons. Neurons are excitable tissue because they can generate action potentials in page517 INTERNATIONAL JOURNAL OF ARTIFICIAL INTELLIGENCE ISSN:2692-5206,ImpactFactor:12,23 AmericanAcademicpublishers,volume05,issue04,2025 Journal: https://www.academicpublishers.org/journals/index.php/ijai response to external stimuli. When the threshold of excitation is reached, the membrane potential changes dramatically, which leads to the propagation of the impulse. Neurons transmit impulses over long distances via axons. The myelin sheath surrounds the axon and increases the speed of impulses. Commu