Plan
► General structure of nervous system. General structure of brain and spinal cord.
► Neuronal theory of structure of nervous system. Structure and classification of neurons.
► Reflex as structural and functional unit of human organism. History of reflex theory (R. Descartes, I. Procházka, I. Sechenov, I. Pavlov, N. Bernstein, P. Anokhin).
► Principles of reflex theory.
► Classification of reflexes.
General Structure of Nervous System. General Structure of Brain and Spinal Cord
Regulatory processes in a human and animal organism are realized through nervous and humoral mechanisms. Humoral regulatory mechanisms are mediated by various chemical compounds that act on effector organs via the internal environment of an organism. The concept of the internal environment was proposed by French physiologist Claude Bernard. He understood the internal environment as the totality of biological fluids of the body - blood, lymph and tissue fluid. Physiological functions are controlled by biologically active substances including hormones, electrolytes and metabolites (by-products of metabolism). Humoral regulatory mechanisms are characterized by a rather long latent period, high inertia, high consumption
of energy and generalized character. Nervous mechanisms are characterized by a short latent period, fast realization, low consumption of energy and a strictly directed action.
The nervous system of a human is divided into central and peripheral. The central nervous system (the CNS) includes the spinal cord and the brain, and the peripheral nervous system consists of peripheral nerves and ganglia which contain nerve cells of the autonomic (vegetative) nervous system (the ANS) (Fig. 7.1) The brain includes two hemispheres, diencephalon, mesencephalon, medulla oblongata, pons Varolii and cerebellum. The spinal cord has a segmental structure and consists of five sections: cervical, thoracic, lumbar, sacral and coccygeal.