See what "bark" is in other dictionaries. Infectious diseases and their treatment

Bark

Olfactory brain

Develops from the ventral telencephalon and consists of two departments: central and peripheral.

Peripheral department (olfactory lobe), located at the base of the brain consists of: olfactory bulb, olfactory tract, olfactory triangle, anterior perforated substance.

Central department represented by the vaulted gyrus, the hippocampus. , dentate gyrus.

The structures of the telencephalon lying above the striatum (roof, lateral and medial walls of the lateral ventricles) are called raincoat(pallium). It is the cloak, which, growing significantly, forming folds on its surface, covers almost all parts of the brain. The surface layer of the cloak, consisting of gray matter, is called the bark. hemispheres. The surface area of ​​both hemispheres is about 1650 cm2. Each hemisphere has three surfaces: upper lateral (the most accessible for observation), medial (the hemispheres are directed towards each other) and lower. large furrows each hemisphere is divided into lobes. Central, or Roland's furrow, located in the upper part of the lateral surface of the hemisphere and separates the frontal lobe (lobus frontalis) from the parietal lobe (lobus parietalis). Lateral, or Silvieva furrow, also goes along the lateral surface of the hemisphere and separates the temporal lobe (lobus temporalis) from the frontal and parietal. Parieto-occipital sulcus separates the parietal and occipital (lobus occipitalis) lobes along the medial surface of the hemispheres. In the depths of the Sylvian furrow lies insular (insula) share, closed on all sides by sections of the bark that “creeped” onto it. In addition, another lobe is often distinguished, which is located deep in the medial surface of the hemisphere and arcuately covers the diencephalon. This is the limbic lobe.

Smaller furrows divide the lobes into convolutions(gyrus). Some of these furrows are constant (observed in all individuals), others are individual (observed not in all and not always), 2/3 of the surface of the cortex form the lateral walls of the furrows, and only 1/3 is located on the surface of the convolutions.

The origin and structure of the cerebral cortex is heterogeneous. Most of the human cortex is new cortex - neocortex(neocortex), phylogenetically the youngest crustal formation. Phylogenetically earlier cortical structures - ancient bark(paleocortex) and old bark(archicortex) - do not occupy most hemisphere surfaces. The laying of a new bark is formed in the lateral parts of the cloak. The new cortex develops intensively and pushes the ancient cortex to the base of the hemispheres, where it remains in the form of a narrow strip of the olfactory cortex and occupies 0.6% of the cortical surface on the ventral surface of the hemispheres, while the old cortex moves to the medial surfaces of the hemispheres, occupies 2.2% of the cortical surface and is represented by the hippocampus and dentate gyrus. In origin and cellular structure, the new bark differs from the ancient and old bark. However, there are no sharp cytoarchitectonic boundaries between them. The transition from one cortical formation to another in the cellular structure occurs gradually. The transitional type of bark is called the interstitial bark, it occupies 1.3% of the total area of ​​the cortex. Thus, most of the surface of the cortex (95.6%) is occupied by the new cortex.

Ancient and old bark.

For ancient bark characterized by the absence of a layered structure. It is dominated by large neurons grouped into cell islands. old bark has three cell layers. The key structure of the old cortex is the hippocampus. Hippocampus (hippocampus), or ammon horn, Hippocampus (hippocampus), or ammon horn, is located mediobasally in the depth of the temporal lobes. It has a peculiar curved shape (the hippocampus in translation is a seahorse) and almost along its entire length forms an invagination into the cavity of the lower horn of the lateral ventricle. The hippocampus is actually a fold (gyrus) of the old cortex. The dentate gyrus is fused with it and wraps over it. As part of the old cortex, the hippocampus has a layered structure. A layer of terminal branches of the apical dendrites of the pyramidal cells of the hippocampus adjoins the dentate gyrus. Here they form a molecular layer. Various afferent fibers terminate on the terminal branches of the apical dendrites and their bases. The apical dendrites themselves form the next - the radial layer. Further, towards the lower horn of the lateral ventricle, there is a layer of pyramidal cell bodies and their basal dendrites, then there is a layer of polymorphic cells. A layer of white matter of the hippocampus (alveus) borders the wall of the lateral ventricle. It consists of both axons of the pyramidal neurons of the hippocampus (efferent fibers of the hippocampus, leaving as part of the fimbria in the arch), and of afferent fibers coming through the arch from the septum. The hippocampus has extensive connections with many other brain structures. It is the central structure of the limbic system of the brain.

All areas of the neocortex are built according to a single principle.

The initial type is a six-layer bark. Layers are presented as follows:

♦ Layer I - the most superficial, about 0.2 mm thick, is called molecular (lamina molecularis). It consists of fibers of apical dendrites and axons rising from the cells of the lower layers, which are in contact with each other. There are few neurons in the molecular layer. These are small horizontal cells and grain cells. All processes of the cells of the molecular layer are located within the same layer.

♦ II layer - outer granular (lamina granulans externa). ♦ II layer - outer granular (lamina granulans externa). The thickness of the outer granular layer is 0.10 mm. It consists of. small pyramidal and stellate neurons. The axons of these neurons terminate in the neurons of layers III, V, and VI.

♦ III layer - pyramidal (lamina pyramidalis), ♦ III layer - pyramidal (lamina pyramidalis), about 1 mm thick, consists of small and medium pyramidal cells. A typical pyramidal neuron has the shape of a triangle, the apex of which is directed upwards. An apical dendrite extends from the apex, branching in the overlying layers. The axon of the pyramidal cell departs from the base of the cell and heads down. The dendrites of the cells of the III layer are sent to the second layer. The axons of the cells of the III layer terminate on the cells of the underlying layers or form associative fibers.

♦ IV layer - internal granular (lamina granulans internus). ♦ IV layer - internal granular (lamina granulans internus). It consists of stellate cells with short processes and small pyramids. The dendrites of the cells of layer IV go into the molecular layer of the cortex, and their collaterals branch in their layer. The axons of the cells of layer IV can rise to the overlying layers or go into the white matter as associative fibers. The thickness of the IV layer is from 0.12 to 0.3 mm.

♦ V layer - ganglionic (lamina ganglionaris) - a layer of large pyramids. The largest cells of the cortex are located in this layer ( giant pyramids Betz anterior central gyrus) (see Fig. 49B). Their apical dendrites reach the molecular layer, while the basal dendrites are distributed in their own layer. The axons of the cells of the V layer leave the cortex and are associative, commissural or projection fibers. The thickness of the V layer reaches 0.5 mm. 93

♦ VI layer of the cortex - polymorphic (lamina multiformis). Contains cells of various shapes and sizes, has a thickness of 0.1 to 0.9 mm. Part of the dendrites of the cells of this layer reaches the molecular layer, while others remain within the IV and V layers. The axons of the cells of layer VI can rise to the upper layers or leave the cortex as short or long associative fibers. The cells of one layer of the cortex perform a similar function in information processing. Layers I and IV are the site of branching of associative and commissural fibers, i.e. receive information from other cortical structures. Layers III and IV are input, afferent for projection fields, since it is in these layers that the thalamic fibers end. Layer V of cells performs an efferent function, its axons carry information to the underlying structures of the brain. Layer VI is also an output layer, but its axons do not leave the cortex, but are associative. The basic principle of the functional organization of the cortex is the association of neurons into columns. The column is located perpendicular to the surface of the cortex and covers all its layers from the surface to the white matter. Connections between cells of one column are carried out vertically along the axis of the column. The lateral processes of the cells are short. The connection between the speakers of neighboring zones is carried out through fibers that go deep into, and then enter another zone, i.e. short association fibers. The functional organization of the cortex in the form of columns was found in the somatosensory, visual, motor and associative cortex.

Separate zones of the cortex have fundamentally the same cellular structure, however, there are also differences, especially in the structure of layers III, IV, and V, which can break up into several sublayers. In addition, the essential cytoarchitectonic features are the density and size of cells, the presence specific types neurons, location and direction of myelin fibers.

Cytoarchitectonic features made it possible to divide the entire surface of the cortex into 11 cytoarchitectonic regions, including 52 fields (according to Brodman). Each cytoarchitectonic field is indicated on brain maps by a number that was assigned to it in the order of description. It should be noted that there are no sharp boundaries between the cytoarchitectonic fields; the cell layers smoothly change their structure when moving from one field to another. Each field of the cortex performs a specific function. Part of the cortical fields are sensory. In the primary sensory fields, projection afferent fibers end. From the primary sensory fields, information is transmitted via short associative fibers to the secondary projection fields located next to them. So, fields 1 and 3, occupying the medial and lateral surface of the posterior central gyrus, are the primary projection fields of skin sensitivity of the opposite half of the body surface. The areas of skin located next to each other are also projected next to each other on the cortical surface. Such an organization of projections is called topical. In the medial part, the lower limbs are represented, and the projections of the receptor fields of the skin surface of the head are located the lowest on the lateral part of the gyrus. In this case, areas of the body surface richly supplied with receptors (fingers, lips, tongue) are projected onto a larger area of ​​the cortex than areas with a smaller number of receptors (thigh, back, shoulder). Field 2, located in the lower lateral part of the same gyrus, is a secondary projection field of skin sensitivity. Fields 17-19, located in the occipital lobe, are the visual center of the cortex, the 17th field, which occupies the occipital pole itself, is primary. The 18th and 19th fields adjacent to it perform the function of secondary associative fields and receive inputs from the 17th field. The auditory projection fields are located in the temporal lobes. Next to them, on the border of the temporal, occipital, and parietal lobes, are the 37th, 39th, and 40th, which are characteristic only of the human cerebral cortex. In most people, in these fields of the left hemisphere, the speech center is located, which is responsible for the perception of oral and writing. Field 43, which occupies the lower part of the posterior central gyrus, receives taste afferents. The structures of olfactory sensitivity u send their signals to the cerebral cortex without switching in other parts of the CNS. The olfactory bulbs are located under the lower frontal lobes. The olfactory tract begins from them, which is the first pair of cranial nerves (p. Olfact o rius). Cortical projections of olfactory sensitivity are the structures of the ancient cortex.

motor areas the cortex is located in the precentral gyrus of the frontal lobe (in front of the projection zones of skin sensitivity). This part of the cortex is occupied by fields 4 and 5. From the V layer of these fields, a pyramidal path originates, ending in motor neurons spinal cord. The location and ratio of the innervation zones is similar to the projection representation of the skin analyzer, i.e. has a somatotopic organization. In the medial parts of the gyrus there are columns that regulate the activity of the muscles of the legs, in the lower part, at the lateral groove - the muscles of the face and head opposite side body.

Afferent and efferent projection zones crusts occupy a relatively small area. Most of the surface of the cortex is occupied by tertiary or interanalyzer zones, called associative.

Association zones the cortex occupy a significant space between the frontal, occipital and temporal cortex (60-70% of the new cortex). They receive polymodal inputs from sensory areas.

Association zones provide integration touch inputs and play essential role in the processes of higher nervous and mental activity.

0 Young people love jokes and jokes, because basically the educational process causes only boredom and irritation. Schoolchildren and students need to unload their brains so that they can start studying with renewed vigor the next day. However, in order to understand the meaning of banter, you need to know perfectly the teenage slang .. Add it to your bookmarks, it won't get worse in any way! Today we will talk about such a strange at first glance term, it is bark, which means in slang, you can read a little later.
However, before continuing, I would like to recommend you a few more popular publications on the subject of street slang. For example, what does Derbanit mean, what does Show off mean, who is TPshka, what is Dripka, etc.
So let's continue what does cory mean in slang? This term is an abbreviation for the word "jokes", although many citizens have their own opinions about its origin.

bark- this is the name of a certain funny situation, usually in the plural

Synonym of Kora: crusts, jokes, jokes, banter, jokes.

Example:

Do you remember what barks were at the check-in last time?

Tolyan soaked such bark that everyone fell under the table with laughter.

Ha, there were such barks at work this afternoon, until the evening they could not calm down, everyone was laughing.

Peel wet- means action, that is, when someone does something out of the ordinary funny; unexpected or daring escapade

Synonym for the expression Wet crusts: soak the bark, soak the number, fry tasks.

Example:

Let's invite Marinka to a bachelorette party from a parallel class, she wets such crusts that she won't let us get discouraged.

Recently, Tolyan came from Italy, told how he spent the weekend, well, he’s healthy to wet the crusts, we all got angry.

Yesterday at the dance we soaked such crusts.

Kora in youth slang - so in some cases they call shoes

Example:

I don’t have money for top cores, I’ll take cheap envelopes for myself.

For three seasons I have been carrying bark for 700 rubles, much better than branded ones.

Look at those black barks on the elastic band.

After my trampled Nikes, the abibas bark did not come to me at all.

Some are still convinced that the expression " wet the crust", is directly related to "wet the beds." In the sense that the person was so funny that he peed himself with laughter. In addition, there is a strong association that a certain citizen can slip on a watermelon peel, after which everyone will laugh to tears.

There is another version of the origin, but in my opinion it is clearly far-fetched. The point is that previously used for bandaging, different clean, but old rags. In order to unstick them from the wound, it was necessary to soak lint (threads of various lengths used for dressing wounds). The doctor regularly did dressings, and in order to somehow distract a person from this painful procedure, he told jokes and funny stories. As a result, over time, the expression "wet the lint" smoothly changed to "wet the crust".

This version seems implausible to me, but since it exists, I decided to add it to the article.

Wood is considered a source of strength. It is enough to hug him and stand a little, closing his eyes. But no tree will grow if its trunk is left unprotected. What is the bark of a tree called? It is rightly called the skin of a plant, which is a protective cover of the trunk. The bark of a tree occupies about a quarter of its total volume. It depends on the breed, age and growing conditions. The thicker the stem, the more bark. In mature trees, its volume decreases. On the contrary, it increases if the growing conditions of the tree have deteriorated.

What is the protective layer of the trunk?

is an important part of it. It protects the trunk from damage and harmful effects of the external environment, regulates the process of respiration and nutrition. Any, even the smallest, change in the surface of the bark can lead to the death of the entire tree if left untreated. The structure of the bark of a tree suggests the presence of inner and outer layers.

• The inner layer is bast. It is represented by living cells, participates in the transport of nutrients from the crown to the roots of the tree and stores its reserve supply. The bast consists of three types of cells and tissues. The most important are the sieve elements. In coniferous trees, these are cells, and in deciduous trees, they are tubes.
• The outer layer is cork. It's called a crust. The structure of the tree bark provides for a unicellular layer of living cells, which alternately divide in both directions, due to which the tree grows in thickness. The bark directly protects the trunk from environmental influences and consists of three layers. middle layer The bark of the tree contains a special substance - suberin. Thanks to him, its hydrophobicity is ensured.

Tree bark: types

The bark has protective, conductive, healing properties. And it complements the landscape of your site with a texture, restrained colors and decorates it in the winter cold. Each tree is different and different: a unique pattern, color, which can be red, white, green, gray and orange, the nature of the surface. On this basis, the types of tree bark are:

• Smooth.
• Furrowed. These longitudinal and transverse stripes are especially clearly visible in oak and ash.
• The scaly species of tree bark are easy to distinguish. The trunk is covered with scales that exfoliate well. A striking representative is Larch covered with furrowed-scaly bark, which is formed by layering scales one on top of the other.
• Fibrous. This type of bark is characterized by exfoliation of long longitudinal strips, like in juniper.
• Warty. The bark of this species is characterized by small warts. A typical representative is the warty euonymus.

Diseases of the bark

Trees, like people, are susceptible to various diseases. From what do they arise? There are many reasons why trees get sick. An indicator of their state of health is the bark of a tree. She, like human skin, is very vulnerable. But, unfortunately, she is not able to take care of herself. The bark provides this care to a person, endowing him with a bountiful harvest in the future or delighting him with his appearance. The protective layer of the trunk is damaged by infectious diseases, pests, animals, frost, sunlight. And sometimes it simply does not keep up with the growth of the plant and cracks, forming deep wounds. Only good care and timely treatment will not allow the tree to die.

Black cancer

Often the bark falls off, forming open wounds. The disease develops gradually, affecting the trunk and branches, clasping them in a ring. The diseased cortex is great place for overwintering the fungus. Black cancer arises and develops due to burns, cracks and wounds. Weak development of trees accompanies the occurrence of this disease. Black cancer is affected at any age, but older plants are more vulnerable.

Cytosporosis

This disease often affects old trees that are 20 years old or more. The infection penetrates under the bark of the trunk and branches due to wounds on it received from burns, frost, various pests and large animals. The bark of the tree is covered with a red-brown coating and becomes bumpy over time. Cytosporosis quickly spreads to healthy tissues. For one and a half to two months, the branches completely dry out. Over time, the tree will die if left untreated.

dropsy cancer

This tree disease is distinguished by dark spots on the bark. Infected areas die, and depressions appear in place of the dead layer. A brown viscous liquid with a repulsive odor flows out of them. This is the dropsy cancer. Young trees die within one year, and old ones after a few years. If the disease has covered most of the bark, the tree can no longer be saved. To prevent the infection from spreading to other plants, they should be dug up and burned.

Infectious diseases and their treatment

How to treat tree bark from black cancer? First of all, the source of infection is eliminated. To do this, burn all the fallen leaves. In them, fungal spores live even in winter. When the annual pruning of diseased branches is carried out, the garden tool must be treated with blue vitriol so as not to cause infection.

If the bark of a tree is damaged by cytosporosis, you need to remove the affected area and treat this place. Then cover it with var and bandage it with a clean, dry cloth.

Circular lesion of the layer: how to treat?

If the damage to the bark has gone in a circle and captures the root neck, the tree may die. And if such a lesion is seen in the upper part of the trunk and branches, the tree has more chances for recovery. Wounds can be healed by grafting cuttings. If this does not help, you need to transplant the bark from a healthy tree. If the wounds are very small, you can wrap them with transparent polyethylene without covering them with pitch.

How to treat tree bark if it is covered with lichen? Treatment should be carried out in spring or autumn in wet weather. To do this, with a hard nylon or metal brush, lichens are cleaned from the bark. First you need to lay burlap around the tree. After cleaning, all this is burned and buried deep in the ground. The cleaned bark and soil under the tree are sprayed. You can wash the trunk and branches with a soapy-ash solution. Half a kilogram of ash, one and a half kilograms of lime are diluted in a bucket of water and insisted for several days. After spraying, the trunks and large branches of trees are whitened. Lichens begin to turn red and fall off.

Prevention of cortical diseases

In order to prevent various diseases of the bark of trees, you need to regularly carry out prevention. It is as follows:

• The trunk and main branches are cleared of old bark, which prevents the growth and thickening of the tree.
• Mosses and lichens are removed.
• Disinfection is being carried out. It is needed to destroy moss and lichen spores, pests and their larvae. Damaged tree bark is thoroughly washed with a soapy-ash solution. They also spray the crown, but the solution is diluted with water several times. You can wash the barrel by dissolving 100-200 g in a bucket of water. In its absence, iron sulfate is used. But it needs more per bucket of water, 600-800 g. Gardeners often use oxalic leaves for disinfection. To do this, on the bark, you need to remove all the growths to the very wood, level the wounds along the edges and rub with a sorrel leaf. They will quickly tighten with a new protective layer.
• Cracks after disinfection should be covered with pitch or a mixture of clay and lime. If nothing, just whiten.

Often hollows can be seen on the trunk and branches. They eventually lead to the death of trees due to developing infection. They definitely need to be sealed. To begin with, garbage is removed from the hollow, the bark and wood are cleaned from rot. Then disinfection is carried out with iron sulphate. After that, the hollow is sealed with pieces or a mixture of lime with cement and sand. If the hollow is very large, it is clogged with stones, rubble, bricks and poured with cement mortar.

Thermal damage

Trees in the process of growth are subject to a sharp temperature drop, when during the day the bark is strongly heated by the sun, and at night it cools. This leads to the formation of frost holes, cracking and sunburn. Thermal damage is dangerous because it causes partial or complete death of the bark, which occurs due to blockage of the vessels through which nutrients move. This disease is called necrosis and is characterized by the sinking of the affected tissues. Frost crackers can be easily identified by the bark separated from the trunk, where pests and all kinds of fungi settle and breed. If frost holes are not identified and neutralized in time, hollows may form.

Tree bark diseases can be caused by the sun's rays, when their direct hit leads to burns. This usually happens with the onset of spring, when the daytime air temperature becomes positive, and the night temperature becomes a big minus. There is a cooling of the internal and external parts of the tree. As they cool, they shrink. Moreover, the outer parts are faster than the inner ones. As a result of this, a rupture of the cortex occurs. To prevent it, the trunks and branches of trees are whitened and tied with burlap before the onset of winter cold.

Prevention of thermal damage to the cortex

• Water the tree regularly from spring until frost.
• Do not apply nitrogen fertilizers late in the fall.
• Whitewash trees twice a year. This will protect them from the formation of frost holes and sunburn. Whitewash smoothes out temperature fluctuations on the bark. The trunk, skeletal branches and their lower part are treated with a solution of lime. In order for the lime to stick better to the bark, you need to add 50 g of wood glue to a bucket of mortar.

Or branches, more or less easily separated from the inner (much denser) mass of wood. In botany, bark (in woody plants) is a collection of various tissues located between the skin and the cambial ring. The cells of the cambium are very tender, they are torn more easily than others, and therefore the bark is easily torn off in this place from the wood lying under it.

Japanese maple bark.

Growths at the site of injury in a young ash tree.

According to the texture and pattern of the bark, there are:

• trees with smooth bark (beech, hornbeam, ailanthus, cherry);
• trees with lamellar bark (chestnut, sycamore, eucalyptus);
• trees with finely fissured bark (pear, liriodendron, ginkgo);
• trees with deeply fissured bark (pedunculate oak, white willow).

Structure

Distinguish primary and secondary bark. The primary cortex represents the peripheral part of the so-called basic tissue; it is a permanent tissue. The secondary cortex is born from the cambium and, thanks to the activity of the latter, gradually thickens [A slight thickening of the primary cortex occurs only when the so-called. periderm. They call her something else phloem or bast. Under the latter title, it will be considered in more detail.

For the secondary cortex, see Lub

Primary cortex

The primary cortex is composed of parenchymal cells, often containing chlorophyll and starch grains. In it, in turn, it is often possible to distinguish between the outer and inner parts. The first part is adjacent to the skin and consists of cells tightly closed to each other, often turned into bundles of collenchyma or sclerenchyma. The second part consists of thin-walled cells, loosely interconnected, with small intercellular spaces. In water and marsh plants, the latter reach considerable sizes, often merge with each other, forming large air cavities and channels, usually separated from each other by only one layer of cells (Intercellular spaces). Sometimes such channels continuously stretch through the entire internode (for example, in representatives of the genera Hippuris, Ceratophyllum, Myriophyllum), in other cases they are interrupted by transverse partitions ( Marsilia, Potamogeton, Butomus and etc.).

Endoderm

The innermost layer of cells of the primary cortex forms the so-called. endoderm, otherwise protective or protective layer or protective sheath, enveloping the entire secondary cortex, and at the same time - the entire system of vascular fibrous bundles or, in the terminology of Fan-Tigem and his followers, the “central cylinder”. Endoderm exists in stems and roots, but in the latter it is much more pronounced. Endoderm cells have special device: on their radial walls (with which they tightly adjoin each other) characteristic wavy folds are noticeable, which appear in the form of especially typical dark spots (Caspari spots) on transverse sections. Initially, thin, purely cellulose membranes of cells gradually cuticularize; in this case, the process of cuticularization begins with the folds just mentioned and finally captures (in most cases) the entire shell. Tightly closed cells separate the system of the primary cortex from the system of vascular bundles, serving for the latter as a "protective sheath". This is of significant physiological significance. Atmospheric air penetrating through the stomata into the intercellular cavities of the primary cortex cannot, thanks to the endoderm, from the latter enter the waterways of the vascular bundles and interfere with the movement of water here. For the same reason, the air in the histological elements of the vascular bundles may have a different composition and be under a different pressure than the atmosphere surrounding the plant. However, the endoderm does not prevent the free exchange of water and substances dissolved in it between the primary cortex and the "central cylinder" (in the root, for example, water absorbed by the root hairs freely flows to the latter). Often, over time, the shells of endoderm cells become more or less strongly thickened and stiffen, and usually more on the inner walls than on the lateral (radial) ones. However, in some cells, the membranes still remain thin, do not thicken and do not cuticularize: during the movement of substances, such cells play the role of passages or gateways (Durchlasszellen) in the endoderm. Wavy folds on the radial walls, cuticularization of the membrane and abundant accumulation of starch are the signs that distinguish the cells of the protective sheath from neighboring ones. In aerial stems, where the endoderm, as already mentioned, is not as clearly expressed as in the roots, a large accumulation of starch is a particularly typical feature, due to which the endoderm is often called here. starchy vagina. According to Sacks and some other botanists, the movement of starch through the plant occurs mainly through this sheath.

Photo gallery

Usage

According to the Czech studies of Rectoris, percentage bark to all wood pulp is:

Oak branches give (according to Greba) 8-10% more bark than trunks. How much the reduced ratio changes with the size of the trees can be seen from the Hessian studies of Walter: for stakes it ranges between 15.5-28.6%, the average is 27.2%, the pole (0.1-0.2 cubic meters) 10, 2-14.5%, average 12.0, thin trunks (0.2-0.7 cubic meters) 7.0-15.2%, average 11.6 and large trunks (0.7-2.0 cubic meters) 7.7-12.4%, average 9.8. In oak bark (according to Greba) 24.3%, by volume of the total mass; smooth "mirror", 21.4% good cracked and 16.8% rough, of little value.

The bark in most cases has almost no value, although sometimes it serves as a material for various products - it is subjected to mechanical or chemical processing; so, the bark of oak, many willows, spruce, larch and partly birch (actually "greenery" without birch bark, in Siberia and Norway) and alder is used as "bark-dublo", "tank" or "oak" when dressing leather (see. Tanning materials) and then, after soaking, goes abroad to prepare a briquette.

The bark of the cork oak delivers the cork; birch bark is a material for a wide variety of products and for extracting tar. The bark of linden, willows and elms gives a bast for bast production and, in addition, the first one is a bast for matting and sacks, a splint for various handicrafts. Surfacings for self-propelled boats and seines are made from the bark of the sedge. Roofs made of pine bark (Novgorod province) are much better than straw ones; spruce bark is used for bedding under dranichny roofs. From willow bark (Salix purpurea and Salix helix) salicin is extracted, ropes are twisted for seines, etc. Alder and walnut bark is suitable for dyeing black and brown colors; from the bast of the broom ((Citysus laburnum and (Citysus alpinus) weave beautiful hats in Italy, etc.

In the North-West of Russia, the percentage of spruce bark ranges from 9-10.5%.

Bark harvesting at the beginning of the 20th century

The best time for harvesting the bark is when the juices in the tree are fully moving, when it easily lags behind the wood - “removed with a stocking” or a single piece. “Baking” or “skinning” is carried out, depending on the purpose of harvesting the bark, both on felled and growing trees, for example, when harvesting bast, birch bark, oak and bast, you can use trees standing on the root, making longitudinal and transverse cuts bark with an ax or "pawn" - an iron chisel on a long handle - and tearing the bark from the wood with a pawn or a simple stick with a pointed oblique cut, end, or directly with your hands. When tearing off the bark-double, it is not separated from the rest of the bark by an upper incision, but left to hang and dry on the trunk, under the protection of the tree crown. In growing trees, the bark is removed only from the trunk, but on the branches and branches, often more valuable in terms of its qualities, it remains and unproductively disappears. Birch bark for products, linden k. for popular prints, and pine and spruce for roofs are more conveniently harvested from felled trees in the same way as from growing ones, and the tools used to remove oak k., similar in general, are found in Germany and Austria-Hungary very different size, shape and type of iron, wood and bone and names. oak spoons, cutters, chisels, etc.

To reduce the cost of peeling the bark and producing it in winter, when the working day is cheaper, artificial debarking was invented with the help of steam. Metra apparatus - a kind of steam engine, in which steam from one part of a horizontal boiler passes to another, where the material to be debarked is placed in a box; after steaming, the bark easily lags behind the wood. Even better is another Nosmaison apparatus, consisting of a movable boiler cylinder on two wheels, at the bottom of which steam is extracted, which, after overheating in the upper part to 200-250 °, enters the barrels where the barking material is placed. Up to 1000 kg is cleared of bark per day. The Morge apparatus was also used, which represents savings in work, in comparison with manual debarking, in a ratio of 1:6.

According to Grebe's research, the damper the location, the smaller the bark in terms of volume, but it is heavier. In the same way, on sandy and clay soils, the amount of oak K. is the same, but on the first it is heavier. The quality of the duplicate is affected

• type of economy (low-stemmed, especially in the form of logging, deserves preference);
• felling turnover, which should be close to the age of the greatest annual increase and to obtain only C., is 14-20 years. In this case, the income from felling the tithe, on average, is 515 pounds. and 13 cu. soot;
• completeness of plantings - timely, in due measure, the production of cleaning, thinning and passing cuttings;
• the composition of the plantation: with a significant admixture of secondary tree species, oak cod is thinner, and therefore less is obtained from each tree. According to Neubrand, when moving from a mixed plantation to a pure plantation, income increases, on average, up to 21%, and due to the replenishment of the plantation, after cutting down, with oak, you can get K. with an average cutting down of 50% (Eikmeyer). On the contrary, if even a very moderate number of trees are left “for overmature” or in the form of “beacons” (average farming), the income in the form of K. decreases by 30-35%. With the most careful preservation of the double, the content of tannin in it, even for a short time, changes significantly. In general, "bark farming" in oak forests is one of the most profitable, and is able to give, even on poor soil (Holland), up to 7% of the capital tied to it. Although at the end of the eighties the prices for oak bark fell sharply abroad, as a result of the introduction of a surrogate there - tanning of leather with mineral substances, but at present the demand for oak bark is again starting to increase [In Germany, 410,000 dess. under oak oak forests, but to meet the demand of all of Europe for oak oak forests, an area of ​​oak forests of about 35,000 0 0 dec. is needed.].

Wed Hohenstein, "Die Eichensch äl-Wirthschaft" (); Tribolin, "Der Eichenschä lwaldbetrieb" (); Fv. Hohnel, "Die Gerberinden" (); F. Arnold, “Dublo and oak forests” (“Journal of manuf. and trade”, , VI); V. Sobichevsky, “On the return of oak low-barrels in order to obtain a double for leather dressing” (“Notes of the Imperial General. Agricultural. Southern Russia ”, , vol. II); M. Yoelson, “On the return of oak low-barreled ones in order to obtain a mirror K. for tanning”, (“Forest Journal”,). Ivovaya K. - “zadubye” or “crust” (St. Petersburg lips), “broom” - is used in our country mainly as a doublo, occasionally - as an ornamental material for some wickerwork, for example. sandals; a proper willow bark economy has not yet been established. Distinguish (Penz. Gubernia) in trade three varieties of willow K.: ramen or forest bark - the highest grade harvested from hairy or shaggy willows (Salix caprea S. aurita, S. cinerea); tall or ditch bark - K. tall or willow willows (S. viminalis, S. fragliis, S. pentandra, etc.) with a smooth leaf, and willow bark; the latter has a reddish color and a brown underside - the "lining" - and therefore its admixture with the highest grades of grayish-white color with a white lining, often practiced by merchants, is easily recognizable by eye. The amount of willow K. consumed in our country, for lack of accurate data, can be judged approximately; for example, from Finland alone it is annually brought to St. Petersburg. over half a million pounds. The release of "woody k.", mainly double, from Russia abroad is insignificant; exported: g. - 57064 pd. (44135 rubles), city - 55232 pd. (34102 rubles) and city - 84300 pd. (57935 rubles). It is likely that the above conditions for the growth of plantations also affect the quality of birch bark and linden K., although they have not yet been studied enough. Regarding accounting for birch bark, see Birch bark. Linden K. is removed both from young trees, and from middle-aged and old ones, but its technical qualities, and therefore its use, are different. To collect young K. - “bast”, “lukon” or “smychin” - K. is stripped from growing trees, leaving bare stems on the root, or they are first cut down. There are bast: a) according to the time of harvesting: first-grass - torn off in the spring - and sling, winter stripping; b) according to the type of workpiece: “tubes” - solid K., removed from the entire stem, and “striped” or “striped” - removed in strips or “ribbons”. Accounting for bark when selling is very diverse in various provinces; here it is necessary to confine ourselves only to giving some names: parties (Minsk, Volyn) - 60 bunches of 40 lyk (Ryaz. provinces); "cops": 60 "hung" by 30 "twisting"; rolled up in "thousands" (Penz), "hundreds" (northern-western and western provinces, Vladim.), with a difference in grades, "bundles" (Vladimirskaya), "burdens" and "burdens" - in 100 pieces (Vitebsk, Tula), 60 large or 100 small - two "half-nos". Occasionally, in some places, bast is sold by weight - by the pood. From the cube fathoms of small linden firewood is 40 pd. raw bast, and from brushwood - 15 pounds. In a cube fathoms of bast (weighing 71 pd.) 104 bunches, 30 pieces each (Vladim.). Of the middle-aged 40-50 year old - "garden" - lindens, not yet completely coarsened K. (actually

The cerebral cortex is a layer gray matter on the surface of the cerebral hemispheres, 2-5 mm thick, forming numerous furrows, convolutions significantly increasing its area. The cortex is formed by the bodies of neurons and glial cells arranged in layers ("screen" type of organization). Beneath it lies white matter, represented by nerve fibers.

The cortex is the youngest phylogenetically and the most complex part of the brain in terms of morphological and functional organization. This is the place of higher analysis and synthesis of all information entering the brain. Here is the integration of all complex forms of behavior. The cerebral cortex is responsible for consciousness, thinking, memory, "heuristic activity" (the ability to generalize, discover). The cortex contains more than 10 billion neurons and 100 billion glial cells.

Cortical neurons in terms of the number of processes, they are only multipolar, and in terms of their place in the reflex arcs and the functions they perform, they are all intercalary, associative. According to function and structure, more than 60 types of neurons are distinguished in the cortex. There are two main groups according to their shape: pyramidal and non-pyramidal. pyramidal neurons are the main type of cortical neurons. The sizes of their perikaryas are from 10 to 140 microns; on the cut they have a pyramidal shape. From them top corner a long (apical) dendrite extends upward, which divides in a T-shape in the molecular layer. Lateral dendrites extend from the lateral surfaces of the body of the neuron. There are numerous synapses of other neurons on the dendrites and body of the neuron. An axon departs from the base of the cell, which either goes to other parts of the cortex, or to other parts of the brain and spinal cord. Among the neurons of the cerebral cortex, there are associative- connecting areas of the cortex within one hemisphere, commissural– their axons go to the other hemisphere, and projection- their axons go to the underlying parts of the brain.

Among non-pyramidal neurons, the most common are stellate and spindle-shaped cells. stellate Neurons are small cells with short, highly branching dendrites and axons that form intracortical connections. Some of them have an inhibitory, while others have an excitatory effect on pyramidal neurons. Fusiform neurons have a long axon that can run either vertically or horizontally. The bark is built on screen type, that is, neurons similar in structure and function are arranged in layers (Fig. 9-7). There are six such layers in the cortex:

1.Molecular layer - outermost. It contains a weave nerve fibers located parallel to the surface of the cortex. The bulk of these fibers are ramifications of the apical dendrites of the pyramidal neurons of the underlying layers of the cortex. Afferent fibers also come here from the visual tubercles, which regulate the excitability of cortical neurons. Neurons in the molecular layer are mostly small, spindle-shaped.

2. Outer granular layer. Consists of a large number stellate cells. Their dendrites go into the molecular layer and form synapses with thalamo-cortical afferent nerve fibers. Lateral dendrites communicate with neighboring neurons of the same layer. Axons form associative fibers that go through the white matter to neighboring areas of the cortex and form synapses there.

3. Outer layer of pyramidal neurons(pyramid layer). It is formed by pyramidal neurons of medium size. Just like the neurons of the second layer, their dendrites go to the molecular layer, and the axons go to the white matter.

4. Inner granular layer. It contains many stellate neurons. These are associative, afferent neurons. They form numerous connections with other cortical neurons. Here is another layer of horizontal fibers.

5. Inner layer of pyramidal neurons(ganglionic layer). It is formed by large pyramidal neurons. The latter are especially large in the motor cortex (precentral gyrus), where they are up to 140 microns in size and are called Betz cells. Their apical dendrites rise into the molecular layer, their lateral dendrites form connections with neighboring Betz cells, and their axons are projection efferent fibers going to the medulla oblongata and spinal cord.

6. Layer of fusiform neurons(a layer of polymorphic cells) consists mainly of spindle-shaped neurons. Their dendrites go to the molecular layer, and their axons go to the visual tubercles.

The six-layer type of structure of the cortex is characteristic of the entire cortex, however, in its different parts, the severity of the layers, as well as the shape and location of neurons, nerve fibers differ significantly. Based on these features, K. Brodman identified 50 cytoarchitectonic structures in the cortex. fields. These fields also differ in function and metabolism.

The specific organization of neurons is called cytoarchitectonics. Yes, in sensory areas the pyramidal and ganglionic layers of the cortex are weakly expressed, and the granular layers are well expressed. This type of bark is called granular. In the motor zones, on the contrary, the granular layers are poorly developed, while the pyramidal ones are well developed. This is agranular type bark.

In addition, there is the concept myeloarchitectonics. This is a certain organization of nerve fibers. So, in the cerebral cortex, vertical and three horizontal bundles of myelinated nerve fibers are distinguished. Among the nerve fibers of the cerebral cortex, there are associative- connecting areas of the cortex of one hemisphere, commissural- connecting the cortex of different hemispheres and projection fibers - connecting the cortex with the nuclei of the brain stem.

Rice. 9-7. The cerebral cortex of the human brain.

A, B. Location of cells (cytoarchitectonics).

B. Location of myelin fibers (myeloarchitectonics).