Anatomical and physiological method for determining central occlusion. Determination of central occlusion. Determination of central ratio
The human olfactory system can be divided into three sections: peripheral (neuroepithelium lining the upper chamber of the nose), intermediate (olfactory bulb and anterior olfactory nucleus) and central (paleocortical, thalamic, hypothalamic and neocortical projections).
The human hoc has three chambers: lower, middle and upper. The lower and middle chambers essentially perform a sanitary role, warming and purifying the inhaled air. The walls of the upper chamber are lined with neuroepithelium. The olfactory epithelium, lining the olfactory region of the nose, has a thickness of 100-150 μm and contains receptor cells, as well as supporting cells located between them (Fig. 6.24). It is painted in yellow due to the presence of pigment in supporting cells and receptors. There is no convincing evidence for the participation of this pigment in the reception of odors. The number of olfactory receptors is very large and is largely determined by the area occupied by the olfactory epithelium and the density of receptors in it. In general, in this regard, humans are classified as poorly smelling creatures (microsmatics). For example, in a number of animals - dogs, rats, cats, etc. - the olfactory system is much more developed (macromatic).
The olfactory receptor cell has a spindle-shaped shape. On the surface of the receptor layer, it thickens in the form of an olfactory club, from which hairs (cilia) extend. Electronic photographs show that each hair contains microtubules (9+2). In the connective tissue layer of the olfactory lining in terrestrial vertebrates there are the terminal sections of the Bowman's glands, the secretion of which covers the surface of the olfactory epithelium. The central processes of the olfactory receptors are unmyelinated nerve fibers, which in mammals are collected in bundles of 10-15 fibers (olfactory filaments - filea olfactoriae) and, passing through the openings of the ethmoid bone, are directed to the olfactory bulb of the brain.
Odor molecules come into contact with the olfactory mucosa. It is assumed that the receiver of odor molecules are protein macromolecules, which change their conformation when odor molecules are attached to them. When odorous substances act on the olfactory epithelium, a multicomponent electrical potential is recorded from it. Electrical processes in the olfactory mucosa can be divided into slow potentials, reflecting excitation of the receptor membrane, and fast (spike) activity belonging to single receptors and their axons. The slow total potential includes three components: a positive potential, a negative turn-on potential (called an electroophthalmogram, EOG) and a negative turn-off potential (Fig. 6.25). Most researchers believe that EOG is the generator potential of olfactory receptors.
Structure and function of the olfactory bulb. In the paired human olfactory bulb, six layers are distinguished, which are located concentrically, counting from the surface (Fig. 6.26):
Layer I fiber - olfactory nerve; Layer II - a layer of glomeruli, which are spherical formations with a diameter of 100-200 microns, in which the first synaptic switching of olfactory nerve fibers to neurons of the olfactory bulb occurs; Layer III - outer reticular, containing tuft cells; The dendrite of such a cell, as a rule, comes into contact with several glomeruli; Layer IV is an internal reticular layer containing the largest cells of the olfactory bulb - mitral cells. These are large neurons (soma diameter at least 30 μm) with a well-developed apical dendrite of large diameter, which is connected to only one glomerulus. The axons of mitral cells form lateral olfactory tract, which also includes the axons of tuft cells.
Within the olfactory bulb, the axons of the mitral cells give off numerous collaterals that form synaptic contacts in various layers of the olfactory bulb; Layers V (internal reticulate) and VI (granular) are often combined into one layer. The bodies of granule cells are contained here. The layer of granule cells directly passes into the cell masses of the so-called anterior olfactory nucleus, which is classified as a third-order olfactory center. In response to adequate stimulation, a slow long-term potential is recorded in the olfactory bulb, at the ascending front and apex of which evoked waves are recorded (Fig. 6.27). They arise in the olfactory bulb of all vertebrates, but their frequency varies. The role of this phenomenon in odor recognition is not clear, but it is believed that the rhythm of electrical oscillations is formed by postsynaptic potentials in the bulb.
Structure and function central department olfactory analyzer. The fibers of the lateral olfactory tract terminate in various parts of the forebrain: in the anterior olfactory nucleus, the lateral part of the olfactory tubercle, the prepiriform and periamygdala areas of the cortex, as well as in the adjacent corticomedial part of the amygdala complex, including the nucleus of the lateral olfactory tract, into which Fibers are also believed to come from the accessory olfactory bulb (Fig. 6.28). Connections between the olfactory bulb and the hippocampus, entorhinal region of the piriform cortex, and other parts of the olfactory brain in mammals occur through one or more switches. From the primary olfactory cortex, nerve fibers are directed to the medioventral nucleus of the thalamus, to which there is also direct input from the taste system. The fibers of the medioventral nucleus of the thalamus, in turn, are directed to the frontal region of the neocortex, which is considered as the highest integrative center olfactory system. Fibers from the prepiriform cortex and the olfactory tubercle go in the caudal direction, becoming part of the medial forebrain bundle. The endings of the fibers of this bundle are found in the lateral preoptic nucleus, in the lateral region of the hypothalamus, the peri-infundibular nucleus and the double nucleus (nucleus ambiguus) of the hypothalamus. From the description of these connections, the close connection of the sense of smell with the feeding and sexual behavior of mammals becomes clear. Based on some psychophysiological observations of human perception of odors, 7 primary odors are distinguished: musky, camphorous, floral, ethereal, minty, pungent and putrefactive.
(bulbus olfaclorius, PNA, BNA, JNA, LNH)
part of the olfactory brain located on bottom surface frontal lobe of the hemisphere big brain and continuing posteriorly into the olfactory tract; contains the bodies of the second neurons of the olfactory analyzer.
View value Olfactory bulb in other dictionaries
Bulb- bulbs, w. 1. A thickened, sometimes spherical stem of certain plants growing underground (bot.). tulip 2. A head of garlic or onion. 3. Pocket watch with a convex thick........
Ushakov's Explanatory Dictionary
Bulb- -s; and.
1. A thickened, often spherical, part of the stem of some plants. L. hyacinth, tulip, lily.
2. Onion head. Cut and peel the onion. Take two onions.
3.........
Kuznetsov's Explanatory Dictionary
Agnosia Olfactory- (a. olfactoria) A., manifested by a disorder in recognizing objects or substances by their smell.
Big medical dictionary
Aura Olfactory- (a. olfactoria) sensory A. in the form of a sensation of smell, often of an unpleasant nature; observed when the pathological focus is localized in the hippocampus.
Large medical dictionary
Olfactory sulcus- (s. olfactorius, PNA, BNA, JNA; syn. B. straight) B., located longitudinally on the lower surface of the frontal lobe parallel to the longitudinal fissure of the cerebrum, separating the straight gyrus........
Large medical dictionary
Taste Bulb— see Taste bud.
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Hair follicle— (bulbus pili) see hair bulb.
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Olfactory lobe- (l. olfactorius, BNA) part telencephalon, combining the olfactory bulb, olfactory tract, olfactory triangle and anterior perforated substance; Before. is........
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Bulb- , in botany - a formation intended for storing stock nutrients and consisting of a short stem and overgrown leaves (scales). In these leaves are deposited........
Scientific and technical encyclopedic Dictionary
Cells Neurosensory Olfactory— (p. neurosensoria olfactoria) see Olfactory cell.
Large medical dictionary
Cells Olfactory— (p. olfactoria, LNH; synonym: K. neurosensory olfactory, Schultze cell) receptor K., perceiving changes in the concentration of odorous substances in the air.
Large medical dictionary
Olfactory cortex- (p. olfactorius) section of the K., related to the olfactory brain; includes the cingulate, parahippocampal and dentate gyri.
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Aortic bulb- (bulbus aortae, PNA, BNA, JNA) expansion of the initial part of the aorta, in the area of which the aortic valve is located and the coronary arteries of the heart arise.
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Bulb of the Internal Jugular Vein Superior- (bulbus venae jugularis superior, PNA) expansion of the internal jugular vein, located in the jugular fossa of the temporal bone.
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Inferior Internal Jugular Vein Bulb- (bulbus venae jugularis inferior, PNA) expansion of the internal jugular vein at the site of its confluence with the subclavian vein.
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Hair follicle- (bulbus pili, PNA, BNA, JNA, LNH; syn. hair follicle) expansion of the terminal part of the hair root, consisting of epithelial cells capable of reproduction, due to which ........
Large medical dictionary
Duodenal bulb- (bulbus duodeni) upper expanded part duodenum, determined on an x-ray in the form of a triangle with its base facing the pylorus of the stomach.
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Posterior Horn Bulb- (bulbus cornus posterioris, PNA) protrusion on medial wall posterior horn lateral ventricle brain, formed by fibers coming from corpus callosum in the occipital lobe of the hemisphere........
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Bulb of the Vaginal Vestibule- (bulbus vestibuli, PNA, BNA, JNA) anatomical formation located between the external opening urethra and the clitoris, which is a plexus of veins........
Large medical dictionary
Olfactory sulcus- (sulcus olfactorius, PNA, BNA, JNA) a narrow depression on the lateral wall of the nasal cavity, located between the nasal ridge and the upper wall of the cavity.
Large medical dictionary
Olfactory Mace- (clava olfactoria, LNH; synonym Van der Stricht olfactory vesicle) a bubble-like expansion of the peripheral process of the olfactory cell, protruding above the surface of the epithelium.
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Olfactory Bulb- (bulbus olfactorius, PNA, BNA, JNA, LNH) part of the olfactory brain, located on the lower surface of the frontal lobe of the cerebral hemisphere and continuing posteriorly into the olfactory tract;........
Large medical dictionary
Olfactory Thread- (filum olfactorium, LNH) a bundle of axon-like processes of olfactory cells passing through the opening of the ethmoid bone into the olfactory bulb.
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Olfactory Strip- (stria olfactoria, PNA) a bundle of nerve fibers on the lower surface of the cerebral hemisphere, emerging from the olfactory tract; distinguish the medial O. p., heading to the subcallosal........
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Olfactory fossa- (fovea nasalis, LNE; blue nasal fossa) a depression on the frontal side of the head of the embryo, resulting from the deflection of the olfactory placode.
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Placode Olfactory- (p. olfactoria, LNE) P., located in front of the neural plate and is the rudiment of the olfactory epithelium.
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Bulb- a modified, usually underground shoot of plants with a short, flat stem (bottom) and fleshy, colorless leaves (scales) that store water and nutrients.........
Large encyclopedic dictionary
Sensitivity Olfactory- (s. olfactoria) Ch. to a chemical effect, realized by the appearance of the smell of the active substance.
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Bulb- (bulbus), an underground (less often above-ground) shoot with a short flattened stem (the so-called bottom) and fleshy, close-knit scale-like leaves; stores water and nutrition. substances (primarily.........
Olfactory Bulb— (bulbus olfactorius), paired formation in the forebrain of vertebrates (partially or completely fused in some fish, birds and tailless amphibians); primary center, department of smell.........
Biological encyclopedic dictionary
ENCYCLOPEDIA OF MEDICINE
ANATOMICAL ATLAS
Olfactory nerves
The olfactory nerves are responsible for the function of recognizing odors. They pass from the receptors of the mucous membrane of the nasal cavity to the olfactory bulbs.
The olfactory nerves transmit information about a specific sense - smell - to the overlying parts of the brain.
OLFACTORY
EPITHELIUM_
The olfactory epithelium is a part of the mucous membrane of the nasal cavity, in which there are specialized olfactory receptor cells that perceive odors. It is located in the upper part of the nasal cavity and on the nasal septum, dividing it into two parts.
Olfactory receptors are specialized neurons (nerve cells) that are capable of detecting odorant molecules in the air.
OLfactory NERVES Information from the olfactory receptors enters the brain along their long processes, or axons, grouped into about 20 bundles. These bundles are the true olfactory nerves, which pass through a thin perforated layer of bone (the cribriform plate of the ethmoid bone) to reach the olfactory bulbs in the cranial cavity.
The fibers of the olfactory nerves form connections
Localization
Frontal lobe cerebral hemisphere brain
Cribriform plate of the ethmoid bone
Olfactory bulb
The two olfactory bulbs receive and interpret information coming from the olfactory nerve fibers.
Olfactory nerve fibers
They start from receptor cells of the nasal mucosa.
Nasal mucosa
The olfactory epithelium of the nasal mucosa contains receptor cells.
(synapses) in the olfactory bulb.
OLfactory Bulbs The paired olfactory bulbs are actually part of the brain. They are connected to the cerebral hemispheres via the olfactory tracts,
consisting of nerve fibers.
In the thickness of the olfactory bulb, the olfactory nerves communicate with large specialized neurons - mitral cells. Their interaction ensures the further transmission of odor information through the nervous system.
Olfactory tract
Nerve bundles emerging from the brain and ending in the olfactory bulbs.
A The fibers of the olfactory nerve pass from the nasal cavity to the brain. The information transmitted through them is interpreted in the olfactory center.
Then, along the axons of the mitral cells, which form the olfactory tract, this information enters the olfactory center of the brain.
Loss of smell
You have rhinitis
howl bands
No swelling of the nose - the resulting inflammation disrupts the mechanism of smell perception.
Loss of smell is called anosmia. It can be unilateral or bilateral, as well as permanent or transient.
The main complaint of patients with anosmia is a decrease in the perception of taste, not smell. The reason:t)is the fact that most taste sensation in humans it is formed due to the perception of the smell of food. Without the sense of smell, the tongue can recognize only four tastes: sweet, bitter, sour and salty.
EFFECTS OF AGING As the body ages, there is a progressive decline in the sense of smell. This is why older people often complain that food has “lost its taste.”
HEAD INJURIES Head injuries can result in rupture of the olfactory bulbs or fracture of the fragile lamina cribrosa. This can lead to anosmia, usually affecting only one side of the nose.
Rhinitis, or inflammation of the nasal mucosa, can develop as a result viral infection, for example for a cold or allergy. This is usually accompanied by nasal congestion and discharge, sneezing, as well as a decrease in the sense of smell due to the involvement of the olfactory epithelium in the process.
The olfactory bulb is the part of the olfactory brain that causes the sense of smell in humans, located on the lower surface in the cerebral hemispheres and moving into the olfactory tract; it contains the bodies of the second neurons of the olfactory analyzer.
This is the projection zone of the primary olfactory sensations. They look like small thickenings, formed from nervous tissue, located on the sides of the longitudinal fissure of the cerebrum below the hemispheres. The olfactory bulbs contain nerve fibers of the olfactory nerve. Closely connected by nerves to the brain.
The sensitivity of the olfactory system thanks to the bulbs is very high: the olfactory receptor is enough to excite only one molecule of an odorous substance, and the activity of a certain number of receptors already leads to the emergence of a complete sensation.
A change in odor intensity is interpreted as a differential threshold and is poorly assessed by people: the difference in odor strength reaches 30–60% of the initial concentration. Adaptation within the olfactory system does not occur very quickly and depends on the overall speed of air flow near the olfactory epithelium and on the concentration of a highly odorous substance.
Interesting existing classifications smells that a person feels:
- aromatic, burnt, sour and caprylic (or goaty);
- aromatic (particularly red clove), balsamic (eg lily), ambrosial (musk), and allium (garlic). Also canine (valerian) and repulsive (some insects), and nauseating (carrion);
- ethereal (such as acetone, fruit, wine) odors; aromatic (among them: cloves, spices, camphor); and balsamic (vanilla, floral); amber musky scents (musk, sandalwood); garlic (chlorine, hydrogen sulfide, garlic); burnt (benzene, creosote, roasted coffee); and caprylic or canine (rancid cheese, rancid fat); nasty (bugs, belladonna); and nauseating (this is feces, a corpse smell);
- fruity, spicy, floral, resinous, and putrid, burnt).
Anosmia - loss of a person's sense of smell
The loss of smell is quite tragic for a person, and can be complete or only partial, depending on certain substances. Anosmia can be acquired or congenital. Acquired sometimes appears after viral diseases, with damage to the nerve pathways or brain, or with changes in air flow due to rhinitis.
The receptors of the entire olfactory system are located in the area of the upper nasal passages. There is a vomeronasal system that includes the vomeronasal nerve, the terminal nerve, and the necessary accessory olfactory bulb in the forebrain.
It is considered as its own representative of the accessory olfactory system in the central nervous system.
According to information electron microscopy structurally united: olfactory club; supporting cell; central processes of olfactory cells; basal cell; basement membrane; olfactory hairs; microvilli of olfactory cells and microvilli of supporting cells.
Spherical thickening– this is the olfactory club, from which 12 hairs grow, about 10 microns each. The olfactory hairs are immersed in a liquid medium, which is produced by Bowman's glands.
The presence of these hairs increases the area of close contact of a particular receptor with molecules containing an odorant. An axon is located below the receptor cell. They correspond to the olfactory nerve, which runs at the base of the skull and is embedded in the olfactory bulb.
The sensitivity spectra of different cells overlap. Moreover, more than 50% of odorous substances are common to two of the many olfactory cells.
Functions of the olfactory bulb (sense of smell)
The coding of odors, as well as their recognition in the very centers of the olfactory system, is based on the special properties of the receptors. In each 
the olfactory bulb registers its electrical response, which is generated by the odorous substance: different odors create their own spatial mosaic from excited or inhibited areas of the tissue of the olfactory bulb.
The central projections that make up the olfactory system are directed to various departments brain: anterior nucleus, olfactory tubercle, prepiriform cortex, periamygdala cortex, go to another part of the entire amygdala complex. This is how the olfactory bulb connects different parts of the “olfactory brain” in just a few switches.
And this ensures a close connection of the olfactory system with other sensory systems, which, in turn, affects human feeding, sexual and defensive behavior.
OLfactory bulb OLfactory bulb
(bulbus olfactorius), paired formations in the forebrain of vertebrates (partially or completely fused in some fish, birds and tailless amphibians); primary center, department of smell. systems. In O. l. olfactory fibers end. nerve and processes sensory information coming from the senses of smell. receptor cells. Evolutionarily, O. l. is one of the oldest parts forebrain. In some marsupials O. l. up to half the length of the hemisphere; in birds and primates it is poorly developed; in toothed whales it is absent. In animals that have a Jacobson's organ, in addition to the main ones, there are additional O. l. Consists of 6 layers. types of cellular elements.
.(Source: “Biological Encyclopedic Dictionary.” Editor-in-chief M. S. Gilyarov; Editorial Board: A. A. Babaev, G. G. Vinberg, G. A. Zavarzin and others - 2nd ed., corrected . - M.: Sov. Encyclopedia, 1986.)
See what "OLFACTURING BULBS" is in other dictionaries:
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