The neural system is an integral morphological and functional combination of various interconnected nervous structures, which together with the endocrine system provides an interconnected regulation of the activity of all systems of the human body and a reaction to changes in the conditions of the internal and external environment. The nervous system acts as an integrative system, linking together sensitivity , motor activity and the work of other regulatory systems ( endocrine and immune ).
The human nervous system is often divided into the central nervous system (CNS) and the peripheral nervous system (PNS). The central nervous system consists of the brain and spinal cord. The PNS consists of all other nerves and neurons that do not lie within the central nervous system. The vast majority of nerves belong to the PNS. The peripheral nervous system is divided into the somatic nervous system and the autonomic nervous system.
The somatic nervous system is responsible for coordinating the movement of the body, as well as for receiving and transmitting external stimuli. This system regulates actions that are under conscious control.
The autonomic nervous system is divided into parasympathetic and sympathetic . The sympathetic nervous system is responsible for danger or stress, and, among many physiological changes, can cause an increase in heart rate and blood pressure and sensory arousal due to an increase in adrenaline in the blood. The parasympathetic nervous system, on the other hand, is responsible for the state of rest, and provides pupil contraction, cardiac slowdown, expansion of blood vessels and stimulation of the digestive and genitourinary systems.