Neurohumoral regulation of muscle activity. The influence of hormones on muscle
The concept of functional systems was mainly based on the study of motor behavior reactions. According to P. K. Anokhin, starting stimulus activity of an organism is the physical factor, which acts on the background of the situational afferentation during the synthesis process in the higher parts of the brain interfaced with congenital and acquired experience (memory) and the dominant motivation. On this basis there is a choice of one or more directed paths functioning of the body, called the decision an
The adopted program with the target unit (the acceptor of result of action) via efferent pathways delivers the Executive signal which actuates the working devices: occur muscle contraction,secretion of glands, etc. and Then from the relevant receptors in the acceptor of the action comes reverse afferentation message about the result of the act. If the latter does not reach the target fixture installation, then the reaction is repeated or adaptation is another way.
Thus, when the motion feedback system informs the Central nervous system on the degree of muscle contraction, tension tendons, the position of the joints and other factors the impact of motor activity.
Thus, the process of physical training physical training of athletes and patients is the conditioned-reflex character with the formation of temporary connections, the improvement and consolidation in the form of formation of a motor skill.
In the formation of motor skill allocate (distinguish) the three successive stages. The first stage (generalization of excitation) is characterized by a wide irradiation of excitation and efferent generalized reaction with involvement of additional muscle groups. In the second phase (concentration of stimulatory-inhibitory processes in motor areas) improve coordination of the various elements of motor skill and relative stereotypy performed: motor acts.
To humoral regulators of the function of the muscular system are the products of metabolism, tissue hormones, hormones of the endocrine glands. The basis for the development of the functional activity of the visceral organs and systems during exercise is the activating action of the adaptive-trophic function of the sympathetic nervous system and the reticular formation, while maintaining the cerebral cortex, the functions of the Central regulatory management in vegetative organs. The essence of neuro-trophic function of the sympathetic nervous system is to maintain the necessary volume of the chemical reactions and power working muscles according to its needs at the moment [Orbeli L. A.].
Neurohumoral regulation of metabolism and energy for muscular activity is demonstrated by the mobilization of the hormonal status of the organism in the system, the cerebral cortex — limbic system — hypothalamus — pituitary — adrenal cortex. Examination of the relevance of hormones of adrenal medulla— epinephrine and norepinephrine — in the autoregulation showed that noradrsnalin increases the concentration of glycogen in skeletal muscles, thus providing them energy. Adrenaline by modifying the activity of glycogen synthesis, accelerates glycolysis and glycogenolysis.
Thus, antagonism of these hormones is the basis of contractile activity and working capacity of skeletal muscle [Andreev S. Bobkova I.]. Activation of the sympathetic-adrenal system is reflected in the increase in the content of catecholamines in plasma. At the same time, during intense anaerobic work and fatigue hormonal activity systems, mobilizing the energy and plastic resources, falls [Viru A. A.].
The ratio of hormone and neurotransmitter of the links of the sympathetic-adrenal system varies depending on the mechanism of energy exchange. Load anaerobic nature is accompanied by an increase in the level of excretion noradrenaline and increased its synthesis in normal ratio and hormonal mediator of the links of the sympathetic-adrenal system. Load anaerobic nature causes rapid activation of the sympathetic-adrenal system with a predominance of hormonal activity level and decrease the metabolism of catecholamines [Barkashov A. B.].
Adrenocorticotropic hormone stimulates the adrenal function and the release into the blood corticosteroids. The weakening of pituitary stimulation on muscle fatigue: reduces the functional activity of the adrenal cortex and the. the most impairs the adaptation to exercise. Somatotropic hormone and vasopressin, the allocation of which is enhanced during intense muscular work contribute to the mobilization of the plastic resources of the organism and restore health.