Senses

The sense organs are anatomical formations (sensory nerve endings, nerve fibers and cells) that perceive the energy of external influences, transform it into a nerve impulse and transmit this impulse to the brain.

Various types of external influences are perceived by the skin, as well as by specialized sense organs: the organ of vision, the vestibulocochlear organ (the organ of hearing and balance), the organs of smell and taste. With the help of the sense organs, which are capable of detecting and transmitting to the brain external influences of varying nature and strength, transformed into a nerve impulse, a person navigates the surrounding external environment, responds to these influences with certain actions. Some external influences are perceived during direct contact of the human body with objects (contact sensitivity). Thus, sensitive nerve endings located in the skin react to touch, pressure (tactile sensitivity), pain and temperature of the external environment (pain and temperature sensitivity). Special sensitive devices located in the mucous membrane of the tongue (taste organ) perceive the taste of food. Other external influences are detected by the body at a distance (distant sensitivity). This function is performed by complex specialized sensitive devices. The organ of vision perceives light, the organ of hearing detects sounds, the organ of balance detects changes in the position of the body (head) in space, and the organ of smell detects smells. The fact of the interaction of the sense organs with the external environment is expressed in the origin of their sensitive devices - specialized nerve cells - from the outer germ layer (ectoderm).

The sense organs developed and formed in the process of the organism's adaptation to changing environmental conditions, their structure and functions became more complex in connection with the development of the central nervous system. The sense organs formed in parallel with the development of the brain. Along with the preserved and developed neural connections of the sense organs with the subcortical nerve centers, with the participation of which "automatic" (in addition to our consciousness) reflex acts are carried out, connections with the cerebral cortex appeared. It is in the cerebral cortex that external influences are analyzed, and the relationship of the organism with the external environment is understood.

The sense organs only perceive external influences. The highest analysis of these influences occurs in the cortex of the cerebral hemispheres, where nerve impulses arrive via nerve fibers (nerves) connecting the sense organs with the brain. It is no accident that I.P. Pavlov called the sense organs in their broad sense analyzers.

Each analyzer includes:

1. a peripheral device that perceives external influences (light, sound, smell, taste, touch) and transforms them into a nerve impulse;
2. conducting pathways through which a nerve impulse reaches the corresponding nerve center;
3. nerve center in the cerebral cortex (cortical end of the analyzer).

The pathways through which nerve impulses from the sense organs are conducted to the cerebral cortex belong to the group of projection exteroceptive pathways of the brain. With the help of the sense organs, a person receives comprehensive information about the outside world, studies it, forms objective ideas about the objects and phenomena surrounding him, and “feels” the outside world.

As a result of the interaction of the organism with the external environment with the participation of the sense organs, the reality of the external world is reflected in the consciousness of a person. A person forms his attitude to external influences, responds to them with actions specific to each situation.

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