The olfactory analyzer: structure and function. Age peculiarities of the olfactory analyzer

With the help of analyzers of different types of people find their way in the world. It is through sight, hearing, smell, and other senses we sense the environment, recognize the danger. Each person has a different analyzers can be developed is not the same. Will try in the article to understand what constitutes the olfactory analyzer. The structure and functions, importance for the health of one of the senses discussed in this article.

The Definition of olfactory organ

Most of the information about the world one perceives through the organ of vision, but without the smell, the picture was not as bright and clear.

The Olfactory system is designed to detect substances that are able to dissolve and possess volatility. This system creates subjective images in the form of certain odors. The value of the olfactory analyzer is that it can provide an objective assessment of the quality of air, food and the environment in General.

If you compare the olfactory organ in man and animals, we can say that for animals this organ is of particular importance. But it can be developed not all the same. For example, there are life forms in which the olfactory analyzer is well developed. For example, some species of butterflies can find your partner by smell at a distance of up to 8 kilometers. All known dogs that can go on the trail of a man, guided by the smell of his things.

Olfactory organ

If we consider the function of the olfactory analyzer, we can note the most important and significant:

1. Analysis of food edibility and attractiveness. Using this system it is possible to determine the degree of suitability of the product.
2. The Formation of eating behavior.
3. Olfactory analyzer directly involved in setting up the system digestion processing of food.
4. Define hazardous for human organism substances.
5. The Formation of sexual behavior, which can vary under the influence of pheromones.
6. This parser is orientation in the environment.
7. Knowledge of the external world is not without olfactory organ.

It Can be noted that people who are deprived of sight, sense of smell may deteriorate, and they are much better smell, which helps them navigate in this world.

Structure of the olfactory analyzer

If we consider the structure of this organ of sense, we can note the following:

1. Peripheral. It includes the receptor cells in the nasal mucosa. They end with cilia surrounded by mucus. It and dissolve odorants. Chemical interaction occurs, which is converted into a nerve impulse.
2. Conductor section consists of the olfactory nerve. On it signals from receptors go in the forebrain where the olfactory bulb is located. It is the initial analysis information, then the pulses will go to the next section of the analyzer.
3. Central division is located in the temporal and frontal lobes of the cerebral cortex. Here is the final must information, the recognition of smell and is the final response of our body on its impact.

Get Acquainted with the structure and functioning of these departments in more detail.

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Peripheral part of the analyzer

Considering the structure of the olfactory analyzer, you must start with the initial division. It is located in the nasal cavity. In these places the mucous membrane is slightly thickened, covered with mucous secretions, which play a protective role, protect from drying out and participate in the removal of the remaining stimuli after exposure.

Here is the contact between the odorous substances and the receptor cells. In the epithelium there are two types of cells:

• Reference. They take part in metabolic processes.
• Olfactory. This is the receptors themselves, which have a large number of cilia to increase the area of contact.

The Olfactory cells have two process, one of which passes to the olfactory bulbs, and the second is in the form of sticks, and ends with a bottle of cilia.

Conduction Department

This division is intended for carrying out of information, therefore, the nerve pathways, which form the olfactory nerve. It consists of separate beams coming in the optic thalamus.

Noticed the connection with the limbic system, which explains the presence of emotions in the process of perception of odors. For example, some odors can cause pleasure, others disgust, and so on.

Central Department of the analyzer

This section includes the olfactory bulb. There is a division in the temporal lobes of the brain.

Located at the front of the pear-shaped lobe of the cortex in the hippocampal region.

Mechanism of perception of smell

For the effective perception of irritating substances, their molecules must first dissolve in the mucus that surrounds the receptor cells. Theninteract with special proteins embedded in the cell membrane.

This type of contact is possible if the shape of a molecule of the stimulus corresponds to the form of the protein. Slimy substance controls the availability of surface receptors for molecules of odorous substances.

After the molecule of the irritant came into contact with the receptor protein changes structure and results by opening of sodium ion channels in the membrane. Sodium ions penetrate and create positive charges that lead to membrane depolarization.

The receptor cells secreted mediator that causes a nerve impulse to parts of the nervous fibers. Thus, in the form of nerve impulses olfactory excitation starts to spread to other parts of the analyzer.

Olfactory system

If present, how does the olfactory analyzer of man, all the work can be divided into several stages:

1. Promotion of odorous stimulus to the receptor cells, which ends the connection with the receptor proteins.
2. Conversion of chemical exposure to odorous substances in the nerve impulse. This phase begins with the accession of the stimulus to the receptor and ends with the generation of nerve impulses.
3. Move nerve impulses to lower nervous center. Can be read as movement towards the olfactory bulb.
4. The Transform of the impulse to the olfactory bulb.
5. Promotion of nerve impulses in the higher olfactory centers.
6. To build an image of irritation to a particular smell.

All these steps sequentially follow each other. If there are problems or violations on one of them, you can say that odor perception is impaired.

Addictive olfactory analyzer

Features of the olfactory analyzer of man, we understand, but it should also be noted that this sensory system is able to adapt. This happens with prolonged exposure to a stimulus.

Adapt the analyzer can occur for a few seconds, and sometimes it takes up to five minutes. It all depends on several factors:

• Duration of contact with the odorous substance.
• Concentration of the stimulus.
• Air flow Rate.

There is quite an extensive group of odorants to which the olfactory analyzer adapts quickly. Takes very little time, and the smell ceases to be felt. A vivid example is the adaptation to the smell of his body, room, things.

To some stimuli habituation is formed slowly or even just partly. When exposed to weak olfactory stimulus within a short time the addiction can manifest in the form of increasing the sensitivity of this analyzer.

It has been established that the development of adaptation occurs not in the first section of the analyzer, and in the last, that is cortical. Often, when long-term effect is the same odorous substance in the cerebral cortex is formed a persistent focus of excitation. In these situations the sense of smell can occur when exposed to other irritants. Sometimes the feeling can become annoying and occurs even in the absence of stimuli. In this case we can talk about the hallucinations, or illusions.

Can only say with certainty that if there is adaptation to one specific smell, it does not affect the perception of other stimuli because all stimuli affect different receptors.

The Theory of perception of smell

Currently, there are more than 10 thousand odorants. All of them can be grouped into seven classes of primary zapahov:

• Tsvetochny.
• Many.
• Muckosky.
• Efirnyi.
• Gnilostnaya.
• Kamforny.
• EDCI.

If there is a mixture of several odors, the olfactory analyzer may perceive as a completely new flavor. Molecules of different substances have different form, for example, camphor smell, has round molecules, and musky - in the form of a disk. In addition, they differ also in their electrical charge: one can have positive and others negative.

There are many theories that try to explain the mechanism of perception of smell. Currently, the most common is the stereochemistry of that claims on the membrane of receptor cells, there are lots of several types. They differ in their structure and electrophilicity. They are able to detect odorous molecules of a certain shape and size.

Types of violations of smell

In addition, the olfactory analyzer developed not at all the same, moreover, can be observed some irregularities and deviations in the work:

• Anosmia is a complete lack of ability to perceive odors.
• Hyposmia – decreased sense of smell.
• Hyperosmia, on the contrary, is observed with increased olfactory sensitivity.
• Parosmia characterizes inadequate perception of smell.
• Violation of differentiation.
• The Emergence of olfactory hallucinations.
• Olfactory agnosia placed in the case, if a person smells something, but can not recognize.

It Should be noted that with age there is a gradual decreaseolfactory sensitivity. The olfactory analyzer is not capable of so clearly and quickly recognize odors. Scientists estimate that in 50 years the average sense of smell in man is reduced by half compared to youth.

Olfactory analyzer and its age features

The first during fetal development of the olfactory analyzer begins to form the peripheral part. This happens already on 8 week of development. Towards the end of pregnancy, but rather, by the end of 8 months, this analyzer is already fully formed.

Immediately after the birth, you can observe the reaction of the newborn smells. This is manifested in the form of facial movements, changes in the heart muscle, respiratory rate, body position.

It is through smelling the baby learns the scent of his mother. This sense organ is an important component of the formation of food reflexes. Gradually when the child grows, there is an increase in the ability of the analyzer to differentiate smells. The subtlety and strength of this process increases by 4 months.

If you compare the ability to perceive and differentiate the odors in the 5-6 years old children and in adults, it is possible to say that the latter is much higher.

These Are the age characteristics of the olfactory analyzer. You can still say that as a result of systematic training, you can significantly improve your sense of smell, but smokers have a risk to lose the sharpness of perception as the components of tobacco smoke have a negative impact on the receptors. Frequent inflammatory disease of the nasal cavity contribute to the reduction of smell.

Here we have considered the olfactory analyzer. The structure and functions it is described with the greatest possible availability. It's safe to say that all the senses are important to humans. If you're having problems with at least one analyzer, it is already possible to say that the adequacy of perception of the world is reduced, lost all the sensations of life. Take care of yourself and your senses.