The sensory organs are anatomical formations (sensitive nerve endings, nerve fibers and cells) that perceive the energy of external action, transform it into a nerve impulse and transmit this impulse to the brain.
Various kinds of external influences are perceived by the skin, as well as by specialized sensory organs: the organ of vision, the pre-cochlear organ (the organ of hearing and balance), organs of smell and taste. With the help of sense organs capable of detecting and transmitting to the brain the external influences that are not the same in nature and strength, the external influences transformed into a nerve impulse, a person is oriented in the surrounding environment, responds to these influences by one or another action. Some external influences are perceived by direct contact of the human body with objects (contact sensitivity). So, the sensitive nerve endings 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 (body of taste), perceive the taste of food. Other external influences are captured by the body at a distance (distant sensitivity). Such a function is performed by complexly arranged specialized sensitive devices. The organ of vision perceives light, the organ of hearing captures sounds, the organ of equilibrium - changes in the position of the body (head) in space, the organ of smell - smells. The fact of the interaction of the sensory organs with the external environment is expressed in the origin of their sensitive devices, specialized nerve cells, from the outer germinal leaf (ectoderm).
The sense organs developed and formed in the process of adaptation of the organism to the changing conditions of the external environment, their structure and functions became more complicated in correlation with the development of the central nervous system. In parallel with the development of the brain, sensory organs were formed. Along with the preserved and developed nervous connections of the sense organs with the subcortical nerve centers, with the participation of which "automatic" (in addition to our consciousness) reflex acts are performed, connections have appeared with the cortex of the cerebral hemispheres. It is in the cerebral cortex that external influences are analyzed, the interrelations of the organism with the external environment are comprehended.
The sensory organs only perceive external influences. The highest analysis of these effects occurs in the cortex of the cerebral hemispheres, where the nerve impulses flow along the nerve fibers (nerves) that connect the sensory organs to the brain. It is no coincidence that IP Pavlov called sensory organs in their broad understanding by analyzers.
Each analyzer includes:
- a peripheral device that perceives an external action (light, sound, smell, taste, touch) and transforms it into a nerve impulse;
- conductive paths along which the nerve impulse enters the corresponding nerve center;
- the nerve center in the cortex of the cerebral hemispheres (cortical end of the analyzer).
Conductive ways in which nerve impulses from the senses are conducted to the cerebral cortex belong to the group of projection exteroceptive conducting pathways of the brain. With the help of the sense organs, a person receives comprehensive information about the external world, studies it, forms objective ideas about the objects and phenomena surrounding it, "feels" the external world.
As a result of the interaction of the organism with the external environment with the participation of sense organs, the reality of the external world is reflected in the mind of a person. A person forms his attitude to external influences, responds to them with specific actions for each situation.