Human analyzers are functional nervousEducation, ensuring the reception and subsequent processing of information obtained from the internal environment and the outside world. Human analyzers, forming a unity with specialized structures - sensory organs, which contribute to obtaining information, are called a sensory system.
Sensory analyzers of a person connect an individualWith the medium by means of conducting nerve pathways, receptors and the cerebral end located in the cerebral cortex. Isolate external and internal analyzers rights. To the external include visual, tactile, olfactory, auditory, taste analyzer. Internal human analyzers are responsible for the condition and position of internal organs.
Types of human analyzers
Human sensory analyzers are subdivided into species depending on the sensitivity of the receptors, the nature of the stimulus, the nature of the sensations, the speed of adaptation, the purpose, and so on.
External human analyzers receive data from the world and later analyze them. They are perceived by man subjectively under the guise of sensations.
There are types of external human analyzers: visual, olfactory, auditory, taste, tactile and temperature.
Internal human analyzers perceive andSubject to the analysis of modification in the internal environment, the indices of homeostasis. If the body's indices are normal, then they are not perceived by man. Only individual changes in the body can cause a person to feel, such as thirst, hunger, which are based on biological needs. To meet them and restore the stability of the organism, certain behavioral reactions are included. Impulses are involved in the regulation of the functioning of internal organs, they provide the adaptation of the organism to its various vital functions.
Analyzers responsible for the position of the body,Analyze the data on the location and position of the body. Analyzers responsible for the position of the body include the vestibular apparatus and the motor (kinesthetic).
The pain analyzer is of particular importance for the body. Painful signals of the body deliver signals to the person that damaging actions occur.
Characteristics of human analyzers
The basis in the characteristic of the analyzer is its sensitivity, which characterizes the threshold of sensation of a person. There are two types of thresholds of sensation: absolute and differential.
The absolute threshold of sensation characterizes the minimal strength of stimulation, which causes a definite reaction.
The differential threshold of sensation describes between the two values of the stimulus a minimal difference, hardly giving a noticeable difference in sensations.
The magnitude of the sensations changes much more slowly than the strength of the stimulus.
There is also the concept of a latent period, which describes the time from the onset of exposure to the onset of sensations.
A visual analyzer helps a personTake up to 90% of data about the world around you. The perceiving organ is the eye, which has a very high sensitivity. Pupil changes in size allow a person to change their sensitivity many times. The retina has a very high susceptibility from 380 to 760 nanometers (billionths of a meter).
There are situations in which
It is necessary to take into account the time required forAdaptation of the eyes in space. Light adaptation is the addiction of the analyzer to strong illumination. On average, the adaptation takes from two minutes to ten, depending on the brightness of the light.
Dark adaptation is the adaptation of the visualAnalyzer to poor illumination, in some cases it occurs after a certain time. During such visual adaptation, a person becomes vulnerable and in danger. Therefore, in such situations it is necessary to be very careful.
The visual analyzer of a person is characterized by sharpness - the smallest angle, under which two points can be perceived as separate. The sharpness is influenced by contrast, illumination and other factors.
Sensation, excited by a light signal,Saves for 0, 3 seconds due to inertia. The inertia of the visual analyzer forms a stroboscopic effect, which is expressed in sensations of continuity of movements, when the frequency of changing images is ten times per second. This creates optical illusions. The visual analyzer of a person consists of photosensitive formations - rods and cones. With the help of chopsticks, a person is able to see the night, darkness, but such a vision is colorless. In turn, the cones provide a color image.
Everyone should understand the seriousness of theDeviations in the perception of color, as they can lead to adverse effects. Among such deviations are most often found: color blindness, color blindness, hemeralopia. Color blinds do not distinguish between green and red, sometimes purple and yellow, which they appear to be gray. A person who has color blindness sees all the colors in gray. The individual suffering from hemeralopia lacks the ability to see in dim lighting.
Tactile human analyzer provides himDefensive-defensive function. The sensory organ is the skin, it defends the body from chemical substances, acts as a protective barrier in the situation of skin contact with electric current, it regulates the body temperature, protects the person from overcooling or overheating.
If a person is disturbed from 30 to 50 percent of the skin and medical aid is not provided, he soon dies.
The human skin consists of 500 thousand points, perceiving the sensations of action on the skin surface of mechanical stimuli, pain, heat, cold.
The peculiarity of the tactile analyzer lies in its high adaptability to spatial localization. This is expressed in the disappearance of the feeling of touch.
The skin depends on the intensity of the stimulus, it can occur for two to twenty seconds.
Analyzer sensation of temperatureSensitivity is characteristic of organisms that have a constant body temperature. Two kinds of temperature analyzers are placed on human skin: analyzers reacting to cold and reacting to heat. The human skin consists of 30,000 points of heat and 250 points that perceive the cold. In the perception of heat and cold, there are different thresholds of sensitivity, the heat points react to changes in temperature of 0.2 ° C; Points that perceive the cold at 0.4 ° C. The temperature begins to be felt for one second of its impact on the body. With the help of analyzers of temperature sensitivity, the body temperature remains unchanged.
The human olfactory analyzer is represented by the bodySensation - a nose. There are approximately 60 million cells that are located in the nasal mucosa. These cells are covered with hairs, 3-4 nanometers long, they are a protective barrier. Nerve fibers, leaving the olfactory cells, send signals of perceived odors to the centers of the brain. If a person smells a substance that is dangerous to his health (ammonia, ether, chloroform and others), he reflexively slows down or holds his breath.
The analyzer of perception of taste is represented by special cells located on the mucous membrane of the tongue. Sensations of taste can be: sweet, sour, salty and bitter, as well as their combinations.
Sensations of taste play a protective role inPreventing the ingress of a substance hazardous to health or life. Individual perceptions of taste can vary up to 20%. To protect yourself from getting harmful substances into the body it is necessary: to try unfamiliar food, how long it can hold it in your mouth, very slowly chew, listen to your own sensations and taste reactions. After that, decide whether to swallow food or not.
The feeling of a man's muscles is due toSpecial receptors, they are called proprioceptors. They transmit signals to the brain centers, reporting the state of the muscles. In response to these signals, the brain directs impulses that coordinate the work of the muscles. Considering the influence of gravity, the muscular feeling "works" stably. Therefore, a person is able to take a comfortable position, which is of great importance in working capacity.
The pain sensitivity of a person has a protectiveFunction, it warns of danger. After the receipt of the signal about pain, defensive reflexes begin to act, such as removing the body from the stimulus. When pain is felt, the activity of all body systems is reconstructed.
Pain is perceived by all analyzers. When the threshold of the permissible norm of sensitivity is exceeded, there is a feeling of pain. There are also special receptors - painful. Pain can carry danger, painful shock complicates the activity of the body and the function of self-healing.
F Possibilities to perceive a world that is full of sounds in its entirety. Some sounds are signals and warn the person of danger.
The sound wave is characterized by the intensity andfrequency. The person perceives them as loudness of a sound. The human auditory analyzer is represented by an external organ - the ear. The ear is a supersensitive organ, it can catch changes in pressure that come from the surface of the earth. The structure of the ear is divided into the outer, middle and inner. It perceives sounds and maintains the balance of the body. Using the auricle, the sounds are detected and determined, their direction. The tympanic membrane vibrates under the influence of sound pressure. Just behind the membrane there is the middle ear, the inner ear, in which the specific liquid is located, and the two organs - the vestibular apparatus and the hearing organ.
In the hearing organ is about 23 thousandCells, which are analyzers, in which sound waves pass into nerve impulses that rush into the human brain. The human ear can perceive from 16 hertz (Hz) to 2 kHz. Sound intensity is measured in whites and decibels.
The human ear has an important and specificFunction - binaural effect. Thanks to the binaural effect, a person can determine from which side the sound comes to him. The sound is directed to the ear shell, which is facing its source. In a person with one deaf ear, the binaural effect is inactive.
Vibration sensitivity is also notLess important than various human sensory analyzers. The influence of vibrations can be very harmful. They are local irritants and cause damaging effects on tissues and the receptors in them. Receptors have a relationship with the central nervous system, their effect has an effect on all body systems.
If the frequency of mechanical oscillations is low (up toTen hertz), then the vibrations spread throughout the body regardless of the location of the source. If such low-frequency influence occurs very often, then under the negative influence are the muscles of a person, which are quickly affected. When the body is exposed to high-frequency vibrations, the zone of their propagation at the point of contact is limited. This causes changes in the blood vessels, and can often cause disruption in the functioning of the vascular system.
Vibration has an effect on the sensory system. Vibration of general effect, impair vision and its sharpness, weakens the photosensitivity of the eyes and worsens the functioning of the vestibular apparatus.
Local vibration reduces tactile, painful,Temperature and proprioceptive sensitivity of a person. Such versatile negative effects on the human body lead to serious and severe changes in the body's activity and can cause a disease called vibro-disease.