General concept of sensations and their functions. The physiological basis of sensations
The primary contact of a person with the outside world and his own organism, which gives him initial information about the properties and conditions of the external and internal environment, occurs through sensations. By sensation it is customary to understand the psychophysical knowledge of individual properties of phenomena and objects of the objective world, i.e. the process of reflecting the direct impact of stimuli on the sense organs, irritation of the latter. Sensation is the subjective (mental) experience of the strength, quality, localization and other characteristics of the impact on the sense organs that arises as a result of this process
Firstly, with the help of the sense organs, the human body receives in the form of sensations a variety of information about the state of the external and internal environment, and as a result, an adequate reflection of the surrounding world and the state of the organism itself occurs.
Thirdly, sensations are not only the source of our knowledge of the world, but also of our feelings and emotions.
A person has a STRONG need to receive impressions about the world in the form of sensations
The doctrine of sensation asserts that objects and their properties are primary, while sensations are the result of the action of matter on the sense organs. At the same time, sensations reflect the world as it exists.
There are other views on the nature of sensations. On the one hand, sensations are seen as the only reality. On the other hand, this is a concept for which sensations are only conventional signs, symbols of external influences.
a mechanical stimulus can cause a sensation of pressure, sound or light, depending on whether it acts on the skin, ear or eye. Based on these facts, I. Müller put forward the hypothesis of a specific energy of the sense organs. The essence of this hypothesis is that sensations do not reflect the real properties of the stimulus, but
only signal the state of our analyzers. That is, according to this idea, sensation does not depend on the quality of the stimulus, but on the specific energy of the sense organ, which is affected by this stimulus. “What our sensations give us reflects the nature and condition of our sense organs, nerves, and not the nature of what causes these sensations,” wrote I. Müller. The conclusion that I. Muller makes is that not
there is a similarity between our sensations and the objects of the external world. However, even if in some cases we perceive the world not as it really is, our sensations are generally adequate to the world, since they allow us to effectively navigate in the environment.
Thus sensations are subjective images of the objective world.
sensation as a mental phenomenon in the absence of a response of the body or in case of its inadequacy is impossible. In this sense, the fixed eye is as blind as the fixed hand ceases to be an instrument of knowledge. The physiological basis of sensation is the neurophysiological process that takes place in the analyzer. Analyzer –
a term introduced by I.P. Pavlov to designate a functional unit responsible for receiving and analyzing sensory information of any one modality. There are three sections in the analyzer.
The first of them is a perceiving organ or receptor designed to convert the energy of irritation into the process of nervous excitation. The second section is a conductor, consisting of afferent nerves and pathways, through which impulses are transmitted to the overlying sections of the central nervous system.
The third – the central section, – consisting of relay subcortical nuclei and projection sections of the cerebral cortex. For the emergence of sensation, the coordinated activity of all three links of the analyzer is necessary.
The impact of the stimulus on the receptor causes the appearance of irritation. The beginning of this irritation is expressed in the transformation of external energy into an internal process, which is produced by the receptor. From the receptor, this process along the centripetal nerve reaches the nuclear part of the analyzer. When excitation reaches the cortical cells of the analyzer, the body responds to irritation. We sense light, sound, taste, or other qualities of stimuli.
excitation, in turn, is transformed into a mental image – the result of the combined activity of all three parts of the analyzer. Therefore, we can say that sensation is the transformation of the energy of external stimulation into a fact of consciousness
Types of sensations and their characteristics
distinguish visual, auditory, tactile, olfactory, gustatory sensations, sensations of movement and balance
The English physiologist C. Sherrington proposed a classification of sensations based on the anatomical location of receptors and their functions. He identified three main classes of sensations: exteroceptive, proprioceptive and
Exteroceptive sensations arise from the action of receptors located on the surface of the body. are the main group of sensations that connects a person with the external environment.
In turn, exteroceptive sensations are divided into contact and distant ones. contact sensations
caused by the impact of the object on the senses. – touch and taste. Distant sensations reflect the qualities of objects located at some distance from the senses – hearing and vision
the sense of smell occupies an intermediate position between contact and distant sensations, since
sensations occur at a distance from the object, but at the same time, the molecules that characterize the smell of the object with which the olfactory receptor contacts, belong to this object
Proprioceptive sensations reflect the movement and relative position of body parts through the work of receptors located in muscles, tendons and joint capsules.
Interoceptive (organic) sensations signal with the help of special receptors about the course of metabolic processes in the internal environment of the body. The receptors for these sensations are located on the walls of the stomach and intestines, the heart and circulatory system and other internal organs. Interoceptors perceive the main
way the action of chemical agents (for example, on the digestive tract). This is the most ancient and most elementary group of sensations. In addition, interoceptive sensations are among the least conscious forms of sensation and always retain their proximity to emotional states. It should also be noted that interoceptive sensations are often referred to as organic.
there are sensations that cannot be associated with any particular modality. Such sensations are called intermodal. These include, for example, vibrational sensitivity, which connects the motor sphere with the auditory one.
. According to most researchers, the vibrational sense is an intermediate, transitional form between tactile and auditory sensitivity.
Genetic classification allows us to distinguish two types of sensitivity: protopathic (more rhyme, affective, less differentiated and localized), which includes organic feelings (hunger, thirst, etc.) and epicritical (more finely differentiated, objectified and rational), which includes the main
types of human sensations. Epicritical sensitivity is genetically younger and controls protopathic sensitivity.
Visual sensations are caused by exposure of the eye to light. waves of a certain wavelength cause a person to experience a certain color. Thus, visual sensations are sensations of color. All colors are divided into two large groups: achromatic colors (white, black and gray) and chromatic
auditory sensations are caused by mechanical influences associated with periodic changes in atmospheric pressure in the appropriate range. All sounds that a person perceives can be divided into two groups: musical (sounds of singing, musical instruments, etc.) and noises (all kinds of squeaks, rustles, knocks etc.). Auditory sensations vary in pitch, volume, and timbre. The height depends on the frequency of the sound wave
Loudness) is determined mainly by the amplitude of oscillations (intensity) of the sound wave, but also depends on the frequency. The unit of measure for loudness is decibels. Timbre distinguishes sounds of the same height and intensity from different sources from each other. Timbre is spoken of as the “color” of sound. Differences in timbre between two sounds are determined by the variety of forms of sound vibration.
Taste is the perception of the properties of stimuli that act on the receptors of the mouth in the form of taste sensations. There are four basic varieties or modalities: sweet, salty, sour and bitter. Taste sensations in most cases are mixed with olfactory ones. The variety of taste depends to a large extent on
admixture of olfactory sensations
Smell is a type of sensation that reflects the chemical properties of volatile substances (called odors). Smells for a person are signs of an infinite number of objects and phenomena. The so-called chemoreceptors are involved in the construction of olfactory (as well as taste) sensations. These include exteroceptors of taste and smell and numerous interoceptors of internal organs that are sensitive to the concentration of carbon dioxide, oxygen, etc. In addition to chemoreceptors, other receptors of the oral mucosa can also play a role in building olfactory sensations: tactile, pain, temperature. Currently, a scheme is used that includes four main
smell: fragrant, sour, burnt, putrid, the intensity of which is estimated on a conditional scale from 0 to 8. • You should also pay attention to the fact that •’• the sensitivity of olfactory and taste receptors increases during a state of hunger
Skin sensitivity , or touch, is the most widely represented and widespread type of sensation throughout the body. Skin sensations refer to the contact type of sensations, that is, they occur when the receptor is in direct contact with an object of the real world. This may cause feelings
four main types: sensations of touch (tactile), sensations of cold, heat and pain
Distinguish touch: passive and active; monomanual and bimanual; direct, instrumental.
Active touch is the process of forming a tactile image of an object in the course of its palpation.
With passive touch, a tactile image of the contour of an object is formed as a result of its sequential movement relative to a stationary hand or fingers. Under these conditions, the image is formed on the basis of only tactile signals
Instrumental touch, carried out with the help of some auxiliary tool (tool) and achieves great accuracy, even when the object being felt is hidden from view
Kinesthetic sensations – sensations of movement and position of one’s own body and its parts, as well as the applied muscle efforts. Using these sensations as an example, one can confirm the fact that not all sensations are formed consciously. They provide coordination of movements, contribute to the assessment of direction, speed and distance to the object. They are formed automatically, outside the control of consciousness, enter the brain
and regulate movements on a subconscious level
Thanks to kinesthetic sensations, a person can determine the position and movement of parts of his body even with his eyes closed. Impulses received by the central nervous system from proprioceptors, due to changes that occur during movement in the muscles, cause reflex reactions and play a significant
role in muscle tone and coordination of movements. In conjunction with sight, touch, and other senses, kinesthetic senses play an essential role in the development of our spatial perceptions and representations.
In addition to muscles, receptors for kinesthetic sensations are also located in other sensory organs. For example, the formation of sensations that contribute to maintaining and maintaining balance occurs due to special balance receptors that are located in the inner ear. In this case, we are talking about the so-called vestibular system of a person.