Autonomic nervous system (ANS)
ANS participates in the management of the functions of internal organs, at the same time adapting them to current needs and controlling the internal environment of the organism. ANS works on the principle of a reflex arc. Through superior autonomic centers in the central nervous system (CNS), complex mechanisms take place, including heart rate control. The vegetative system consists of two parts, peripheral and central.
Peripheral ANS consists of two separate parts - sympathetic and parasympathetic. Almost all organs are innervated by both the sympathetic and parasympathetic, and the response of the organs to their stimulation may be contradictory or almost identical. In general, parasympathetic tone predominates in anabolic processes such as sleep, digestion and recovery, but in muscle work, stress or illness, catabolic processes provided by the sympathetic system predominate. Tonus / total performance of the autonomic nervous system is a sign of the generation of excitement in its neurons and their transmission to the effectors. The activity of these neurons is equipped with excitement from sensors, various levels of the CNS and the action of hormones. In organs that do not have double vegetative innervation, antagonism is provided by a quantitative change in the tone of innervation. The most typical example is the innervation of blood vessels.
The central part of the autonomic nervous system coordinates the activity of the sympathetic and parasympathetic nervous system. At the level of the spinal cord, the interactions of vegetative and somatic afferents and efferents and vegetative reflexes are realized, the reticular formation of the brainstem then plays a crucial role in the control of the respiration and cardiovascular system. Feelings of cold, heat, satiety, thirst, libido, aggression and fear are caused by irritation of the hypothalamus. The hypothalamus is also the highest governing body of the endocrine system, and thus has an important role to play in homeostasis. The allocortex is the youngest integration area of autonomic and somatic functions and the neocortex is the highest control area of autonomic executive CNS functions.