home Audience 1 The spinal cord is connected and conductor of the central nervous system. Spinal cord: structure and functions Spinal cord zones of influence on organs

The spinal cord is connected and conductor of the central nervous system. Spinal cord: structure and functions Spinal cord zones of influence on organs

The human central nervous system performs many functions due to which our body is able to function normally. It consists of the brain and spinal cord.

The spinal cord is the most important part of the human nervous system. The structure of the human spinal cord determines its functions and characteristics of work.

What it is?

The spinal cord and brain are two components of the central nervous system that form a single complex. The cephalic section passes into the spinal section at the level of the brain stem in the greater occipital fossa.

The structure and function of the spinal cord are inextricably linked. This organ is a strand of nerve cells and processes that extend from the head to the sacrum.

Where is the spinal cord located? This organ is located in a special container inside the vertebrae, which is called the “spinal canal”. This arrangement of the most important component of our body is no coincidence.

The spinal canal performs the following functions:

Protects nervous tissue from environmental factors.
Contains membranes that protect and nourish nerve cells.
It has exit intervertebral openings for spinal roots and nerves.
Contains a small amount of circulating fluid that nourishes cells.

The human spinal cord is quite complex, but without understanding its anatomy it is impossible to fully imagine the features of its functioning.

Structure

How is the spinal cord structured? The structural features of this organ are very important to understand in order to understand the entire functioning of our body. Like other parts of the central nervous system, the tissue of this organ consists of gray and white matter.

What is gray matter made of? The gray matter of the spinal cord is represented by an accumulation of many cells - neurons. This section contains their nuclei and main organelles, which help them carry out their functions.

The gray matter of the spinal cord is grouped in the form of nuclei that extend throughout the organ. It is the kernels that carry out most of the functions.

The gray matter of the spinal cord contains the most important motor, sensory and autonomic centers, the function of which will be discussed below.

The white matter of the spinal cord is formed by other sections of nerve cells. This area of tissue is located around the nuclei and represents cell processes. The white matter consists of so-called axons - they transmit all impulses from the small nuclei of nerve cells to the place where the function is performed.

Anatomy is closely related to the tasks performed. Thus, when the motor nuclei are damaged, one of the functions of the organ is disrupted and the possibility of performing a certain type of movement is lost.

The structure of this part of the nervous system is divided into:

Own apparatus of the spinal cord. It includes the gray matter described above, as well as the dorsal and anterior roots. This part of the brain is capable of independently performing an innate reflex.
Suprasegmental apparatus - represented by conductors or pathways that pass both in the overlying direction and in the underlying one.

Cross section

What does the spinal cord look like in cross section? The answer to this question allows us to understand a lot about the structure of this organ of the body.

The incision changes quite a lot visually depending on the level. However, the main components of the substance are largely similar:

At the center of the spinal cord is the spinal canal. This cavity is a continuation of the cerebral ventricles. The inside of the spinal canal is lined with special integumentary cells. The spinal canal contains a small amount of fluid that enters it from the cavity of the fourth ventricle. In the lower part of the organ, the cavity ends blindly.

The substance surrounding this hole is divided into gray and white. The bodies of nerve cells are located on the section in the form of a butterfly or the letter H. It is divided into anterior and posterior horns, and lateral horns are also formed in the area of the thoracic spine.
The anterior horns give rise to the anterior motor roots. The rear ones are sensitive, and the lateral ones are vegetative.
The white matter contains axons that are directed from top to bottom or bottom to top. There is much more white matter in the upper sections, since here the organ must have a much larger number of pathways.
The white matter is also divided into sections - anterior, posterior and lateral funiculi, each of which is formed by the axons of different neurons.

The spinal cord pathways within each cord are quite complex and are studied in detail by professional anatomists.

Segments

A segment of the spinal cord is a special functional unit of this most important element of the nervous system. This is the name of the area that is located on the same level with two anterior and posterior roots.

The sections of the spinal cord repeat the structure of the human spine. So the organ is divided into the following parts:

– in this rather important area there are 8 segments.
The thoracic region is the longest part of the organ, containing 12 segments.
The lumbar region - according to the number of lumbar vertebrae, has 5 segments.
Sacral section - this part of the organ is also represented by five segments.
Coccygeal - in different people this part can be shorter or longer, contains from one to three segments.

However, the spinal cord of an adult is somewhat shorter than the length of the spinal column, so the segments of the spinal cord do not completely correspond to the location of the corresponding vertebrae, but are located slightly higher.

The location of the segments relative to the vertebrae can be represented as follows:

In the cervical part, the corresponding sections are located approximately at the level of the vertebrae of the same name.
The upper thoracic and eighth cervical segments are one level higher than the vertebrae of the same name.
In the middle thoracic region, the segments are already 2 vertebrae higher than the same sections of the spinal column.
Lower thoracic region - the distance increases by one more vertebra.
The lumbar segments are located at the level of the thoracic vertebrae in the lower part of this part of the spine.
The sacral and coccygeal sections of the central nervous system correspond to the 12th thoracic and 1st lumbar vertebrae.

These relationships are very important for anatomists and neurosurgeons.

Spinal roots

The spinal cord and roots are inseparable structures, the functions of which are firmly connected.

The spinal cord roots are located in the spinal canal and do not exit directly from it. Between them, at the level of the inner part of the intervertebral foramen, a single spinal nerve should form.

The functions of the spinal cord roots are different:

The anterior roots always extend from the organ. The anterior roots contain axons that travel from the central nervous system to the periphery. This is how, in particular, the motor function of the organ is carried out.
The dorsal roots contain sensory fibers. They are directed from the periphery to the center, that is, they enter the medullary cord. Thanks to them, sensory function can be carried out.

According to the segments, the roots form 31 pairs of spinal nerves, which already exit the canal through the intervertebral foramina. Next, the nerves carry out their direct function, are divided into individual fibers and innervate muscles, ligaments, internal organs and other elements of the body.

It is very important to distinguish between the anterior and posterior roots. Although they merge with each other to form a single nerve, their functions are completely different. The axons of the former are directed to the periphery, while the components of the dorsal roots, on the contrary, return to the center.

Spinal cord reflexes

Knowledge of the functions of this important element of the nervous system is impossible without understanding the simple reflex arc. At the single segment level, it has a fairly short path:

People have spinal cord reflexes from birth and they can be used to determine the functional viability of a particular part of this organ.

The reflex arc can be represented as follows:

This path begins from a special nerve link called a receptor. This structure receives impulses from the external environment.
Further, the path of the nerve impulse lies along centripetal sensory fibers, which are the axons of peripheral neurons. They carry information to the central nervous system.
The nerve impulse must enter the nerve cord, this occurs through the dorsal roots to the nuclei of the dorsal horns.
The next element is not always present. It is the central link that transmits impulse from the rear to the front horns.
The most important link in the reflex arc is the effector link. Located in the anterior horns. From here the impulse goes to the periphery.
Along the anterior horns, irritation from neurons is transmitted to the effector - the organ that carries out direct activity. Most often it is skeletal muscle.

The impulse from neurons travels through this complex path, for example, when tapping the tendons of the knee with a hammer.

Spinal cord: functions

What function does the spinal cord perform? The characteristics of the role of this organ are described in serious scientific volumes, but it can be reduced to two main tasks:

Reflex.
Conductor.

Completing these tasks is a very difficult process. The ability to implement them allows us to move, receive information from the environment and respond to irritation.

The reflex function of the spinal cord is largely described by the characteristics of the reflex arc presented above. This function of the spinal cord is to transmit and respond to impulses from the periphery to the center. The most important part of the central nervous system receives information from receptors and transmits motor impulses to skeletal muscles.

The conduction function of the spinal cord is carried out by white matter, namely the conduction tracts. The characterization of individual pathways is quite complex. Some conducting fibers are directed upward to the head section, others come from there.

Now you have a general idea of such an organ as the spinal cord, the structure and functions of which determine the characteristics of our interaction with the outside world.

Clinical role

What can the presented information be used for in practical medicine? Knowledge of the structural features and functions of the organ is necessary for diagnostic and therapeutic activities:

Understanding the anatomical features allows for timely diagnosis of certain pathological processes. An MRI image cannot be deciphered without a clear understanding of the normal structure of the nervous system.
Evaluation of clinical data is also based on the characteristics of the structure and functioning of the nervous system. Decreasing or increasing certain nerve reflexes helps determine the location of the lesion.
Understanding anatomical features allows surgeons to perform precise operations on the nervous system. The doctor will act on a specific area of tissue without affecting other parts of the organ.
Understanding brain function should facilitate the development of appropriate conservative treatment methods. Restorative procedures for organic lesions of the nervous system are based on an understanding of the functioning of the spinal cord.
Finally, the cause of death of a person from diseases of the nervous system cannot be established without knowledge of the anatomy and functioning of its constituent organs.

The knowledge gained over centuries of research about the characteristics of the nervous system allows medical practice at a high modern level.

The spinal cord of a person or animal is the most important part of the central nervous system. Through it, the brain communicates with muscles, skin, internal organs, and the autonomic nervous system. This ensures the vital functions of the human body, dog, cat or other mammal. The structure of the spinal cord is distinguished by its complex organization and narrow specialization of each area. Its biology is structured in such a way that any serious disorder manifests itself in problems with motor functions and somatic anomalies.

Externally, this organ is very similar to a cord stretched in a special canal of the spine. It has a right side and a left side. Its length does not exceed half a meter, and its diameter is about a centimeter.

We will consider in detail the structure of the spinal cord, the features of its organization, and the principles of operation. Knowing what the structure of the spinal cord is, you can easily understand how our movements are born, how the activity of neurons can manifest itself. We will also tell you what functions the spinal cord performs.

The spinal cord contains from 31 to 33 pairs of nerves, so it is divided into 31-32 segments. Each corresponds to a part of our body and continuously performs its functions. The mass of such an important organ, without which not a single movement is possible, is only 35 grams.

Location area: spinal canal. At the top it immediately passes into the medulla oblongata, and at the bottom it is completed by the vertebrae of the coccyx.

Segmentation

The role of the spinal cord is to organize all human movements. To ensure maximum efficiency of its work, segments were identified during evolution, each of which ensures the functioning of a specific area of the body.

This part of the nervous system begins to form already in the 4th week of embryonic development, but it will not be able to perform the main functions of the spinal cord immediately.

The sections of the spinal cord and their functions are now well studied. It is segmented into:

cervical segments (8 pieces);
chest (12 pieces);
lumbar (5 pieces);
sacral (5 pieces);
coccygeal (from 1 to 3 pieces).

The human back ends with a small tailbone. It is a rudiment, that is, a part that has lost its significance in the course of evolution. This is actually the rest of the tail. Therefore, a person has very few coccygeal segments. He simply doesn't need the tail anymore.

What is it needed for

The spinal cord is the center that collects all information coming from the periphery. It then sends commands to the muscles and tissues, toning them. This is how all movements are born. This is complex and painstaking work, because a person makes hundreds of thousands of tiny movements per day. Its physiology is characterized by the complex organization and interaction of all parts of the central nervous system.

The spinal cord is reliably protected by three membranes at once:

hard;
soft;
arachnoid.

Inside there is cerebrospinal fluid. The center of the brain is filled with gray matter. In cross-section, this area looks like a butterfly with its wings spread. Gray matter is a concentrate of neurons; they are the ones capable of transmitting a bioelectric signal.

Each segment consists of tens and even hundreds of thousands of neurons. They ensure full functioning of the musculoskeletal system.

There are three types of projections (horns) in the gray matter:

front;
rear;
side.

Different types of neurons are distributed between the zones. This is a complex and well-organized system that has its own characteristics. There are a huge number of large motor neurons in the anterior horn area. Small intercalary neurons are located in the dorsal horns, and visceral (sensory and motor) neurons are located in the lateral horns.

It is the nerve fibers that form the pathways along which the signal is transmitted.

In total, scientists have counted more than thirteen million nerve fibers in the human spinal cord. The protective function for them is performed by the external vertebrae that form the spine. It is in them that the inner delicate and vulnerable spinal cord is located.

The gray matter is surrounded on all sides by many nerve fibers. The transmission of bioelectric signals occurs through the thinnest processes of neurons. Each person may have from one to many such processes. Neurons themselves are extremely small in size. Their diameter is no more than 0.1 mm, but the processes are striking in their length - it can reach one and a half meters.

There are different types of cells in gray matter. The anterior sections consist of motor cells and are very large. As the name itself suggests, they are responsible for motor functions. These are thin but very long fibers that go from the spinal cord directly to the muscles and set them in motion. Such fibers form large bundles and exit the spinal cord. These are the anterior roots. One of them goes out to the right, and the other goes out to the left.

In each section there are such sensitive fibers, from which a pair of roots are formed. Some sensory fibers connect to the brain. The second part is directed directly to the gray matter. The fibers end there. The end for them are different types of cells - motor, intermediate, intercalary. Through them, continuous regulation of movements and organs is carried out.

Organization of pathways

The pathways of the entire body are usually divided into:

associative;
afferent;
efferent.

The task of associative pathways is to connect neurons between all segments. These connections are considered short.

Afferents provide sensitivity. These are ascending pathways that receive information from all receptors and send it to the brain. Efferent pathways transmit signals from the brain to neurons throughout the body. They belong to the descending paths.

Functions

The activity of the spinal cord is continuous. It provides motor activity of the body. There are two main functions of the human spinal cord - reflex and conduction.

Each department ensures the functioning of a completely specific area of the body. Segments (cervical, thoracic, for example) provide the functions of the organs of the sternum and arms. The lumbar segment is responsible for the proper functioning of the muscles and digestive system. The sacral segment is responsible for the functions of the pelvic organs and legs.

Reflex

The reflex brain function is to organize reflexes. This allows the body, for example, to instantly respond to a signal of pain. The action of reflexes is striking in its efficiency. A person withdraws his hand from a hot object in a split second. During this time, information from the receptors to the brain and back has traveled a long way along the reflex arc.

When the sensitive nerve endings of the skin, muscle fibers, tendons, and joints receive irritation, this means that a nerve impulse has been sent to them. Such signals travel along the dorsal roots of nerve fibers and enter the spinal cord. Receiving a signal, motor and intercalary cells are excited. Then, along the motor fibers of the anterior roots, impulses are sent to the muscles. Having received such a signal, the muscle fibers contract. Simple reflexes occur through this mechanism.

A reflex is a reaction of the body in response to received irritation. All reflexes are provided by the work of the central nervous system. One of the functions of the spinal cord is reflex. It is provided by the so-called reflex arc. This is a complex path that nerve impulses travel from the peripheral components of the body to its spinal cord, and from there directly to the muscles. This is a difficult but vital process.

The simplest reflexes can save a person’s life and health. Retracting the hand that touched the hot item, we do not even suspect that the signal from the skin was transmitted with lightning speed along the nerve fibers to the brain, and then to the spinal cord. In response, an impulse was sent that contracted the muscles of the arm to avoid being burned. This is a clear manifestation of the reflex function.

Neurophysiologists have studied in detail almost all reflexes and the neural arches that ensure their implementation. These data allow for effective rehabilitation after injuries and a number of diseases, and also help in their diagnosis.

It is on this reflex that a diagnosis by a neurologist is based, in which the doctor lightly hits the patient’s patella tendon with a hammer. This is how the knee reflex is studied, by which one can judge the state of a certain part of the spinal cord.

However, the spinal cord is not an independent reflex system. Its functions are constantly controlled by the brain. They are closely connected by special bundles of nerve fibers. The fibers are very long, thin, and consist of white matter. Some signals are transmitted upward to the brain, and others - to the spinal cord.

The entire central nervous system is involved in the formation of coordinated complex movements. Each movement is a continuous flow of impulses from the brain to the spinal cord, and from it to the muscle fibers.

Conductor

This is the second important function. It consists in the fact that from the spinal cord nerve signals are transmitted higher to the brain. There, in the subcortical and cortical areas, all information is instantly processed, and appropriate signals are sent in response to it.

The conductor function works in those moments when we decide to take something, get up, go. This happens instantly, without wasting time on thinking.

This function is mostly provided by intermediate or interneurons. They send signals to motor neurons and also process information that comes from the skin and muscles. This is where peripheral signals and impulses from the brain meet.

The excitatory impulse is sent by insertion cells to different groups of motor cells. At the same time, the activity of other groups is inhibited. It is this complex process that ensures coherence and high coordination of human movements. This is how the refined movements of a pianist and ballerina appear.

Possible diseases

The human body has a unique section called the cauda equina. The spinal cord itself is missing, and only cerebrospinal fluid and bundles of nerves remain. If they are compressed, the body begins to experience pain, and disorders of the musculoskeletal system are observed. This disease is called “cauda equina” based on the location of the main cause.

If a horse's tail develops, a person may experience a number of symptoms. Lower back pain appears, muscles experience weakness, and the body begins to respond much more slowly to external stimuli. Inflammation may appear, and the temperature may even rise. If these alarming symptoms are ignored, the condition worsens. It becomes difficult for a person to move or sit for a long time.

All vertebrates have a spinal cord. It is a narrow elongated cord, the length of which is on average 50 cm. It plays the role of a channel connecting the internal organs and the brain, and consists of several membranes, between which there are various kinds of liquids.

Anatomical information

First of all, let's determine where the spinal cord is located and what its structure is. This organ is located in the cavity of the spinal canal, between the processes and cartilages of the ridge. It originates from the brain, namely at the lower border of the foramen magnum. The end point of this organ is located between the 1st and 2nd lumbar vertebrae. At this point, the transformation into the conus medullaris occurs, which, in turn, transforms into the filum terminale. It reaches the tailbone and forms a bundle of nerve connections there, which is called the “cauda equina.” The length of the spinal cord depends on the height of the person and can be either 40 or 50 centimeters. Its weight also varies - from 34 to 39 grams.

Components

Since the spinal cord is the second most important center of the nervous system, it consists primarily of neurons. The organ has three membranes: soft, arachnoid and hard. In the center there is a main channel that transports all impulses to the brain, and the space between it and the tissues is filled with cerebrospinal fluid. The hard outer shell is located in the epidural space, which is filled with fat and a venous network. It is worth adding that the organ has a structure that imitates the spine, that is, it looks like a long thin cord. For this reason, it was not difficult for our ancestors, who worked in the field of anatomy, to determine exactly where the spinal cord is located and to which other organs it is directly “connected.”

Basic “working” elements

The functions possessed by the spinal cord center would be impossible without two substrates - white and gray. They are located directly in the canal of the brain itself, and the amount of one or another substance predominates in different areas. The bulk of the gray substrate is concentrated in the upper part of the tube and in the lumbar region. White matter predominates in the chest area, and the lower it is, the more its amount decreases and gradually comes to zero. When we take a cross section of the spinal cord, we also see that the gray matter is the middle, which looks like the letter H, and it is surrounded on all sides by a white membrane.

Features of gray matter

This substrate consists mainly of nerve fibers, cells and processes. Initially, it seems that the gray matter is the most central part of the brain, but in fact it functions as just another shell, so to speak. In the very center there is a very narrow cavity, which widens slightly only in the area of the cervical vertebrae (at this stage the diameter is less than 1 mm). This cavity is the very channel through which the spinal cord transmits all the necessary information to the brain.

Characteristics of white matter

This substrate has a much more complex structure, consisting simultaneously of different types of cells and tissues, and is also characterized by an unstable thickness. The substance is based on myelinated and unmyelinated nerve fibers and neuroglia, the supporting nervous tissue. All this is shrouded in a web of blood vessels, between which lies connective tissue. Most neurons are collected in bundles, which makes the substrate viscous and dense. Important components of the white matter are the efferent and afferent pathways, to which association fibers join. These elements ensure the connection of all parts of the spinal cord with each other.

How reflexes are formed

The main function of the spinal cord is reflex. Numerous nerve plexuses and channels are adjacent to the organ on all sides, which carry impulses from all components of our body. This system coordinates and directs involuntary movements that occur during sleep, sensations of pain, etc. The reflexes of all vertebrates are relatively identical and are divided into several types:

Flexion reflex - the name speaks for itself. To be more precise, this is a protective function of the body that allows us to remove a damaging stimulus, for example, quickly pull our hand away from something hot.
Proprioceptive is a reflex that prevents excessive stretching of muscle tissue.
Rhythmic and tonic functions are also the task of the spinal cord.
Animals and newborn children have a primitive reflex - an extensor impulse. The bottom line is that when the heel is compressed, the knee joint involuntarily straightens. This function is considered primitive, and if a person, having matured, continues to react to such a stimulus, it means that his spinal cord is damaged.

Connection function

The tube running along the spine is called the brain for a reason. The structure of this organ is similar to the head center, in addition, they are directly connected to each other. The spinal cord contains a whole web of neurons, these fibers stretch to the most remote corners of our body and carry all the information about what is happening inside and outside us. In addition, nerve cells are enveloped in vessels and capillaries, which form into special channels and go directly to the brain. As a result, it turns out that our spine, or rather what is in it, literally collects all the information about the functioning of the organs and transmits it to the main center.

It is worth remembering that any damage to the spinal cord is extremely dangerous. By losing at least one segment of it, you cut the “thread” through which your entire body functions.

Considering the topic “Spinal cord: structure and functions”, you will learn what processes this organ is involved in and what roles it plays in the life of the human body, as well as other vertebrates. This is one of the most complex organs, which consists of fibers even thinner than a thread.

The spinal cord is key organ of the central nervous system all vertebrates, including humans. If signals are generated in the head section, then the spinal section puts them into action: it transmits the signal to the nerves, and they, in turn, affect the muscular system, causing it to contract.

In contact with

Functions of the spinal cord: the main thing

The spinal cord is the most complex structure nerve fiber system, which perform two most important tasks in the life of the body at once:

reflex;
conductive.

Conductive function

What is the conducting function of the spinal cord? Any movement originates initially in your brain. Impulses come to it from the mucous membranes, skin or internal organs, after which it processes them and sends a signal to the spinal cord, and then to the peripheral cord. But in turn transmits signals along nerve endings, which cause your muscles to contract.

When performing a certain movement, a person does not even think about which muscles need to be used at the moment - this function is automatically performed by the spinal cord.

Serious injuries, for example, rupture of an organ, lead to partial or complete loss of a person’s ability to move. In this case, the information is simply does not reach the nerve endings which would cause the muscles to contract.

Here this organ acts as an intermediate link. The conductive function of the spinal cord is very important.

Reflex function

Each of you has probably accidentally touched a hot frying pan. Your nerve endings react to high temperature, which is an irritant. This information is sent directly to the spinal cord. In response to contact with a hot surface the uncontrolled reflex function of the spinal cord is involved, causing muscles to contract sharply. This contraction will cause you to immediately withdraw your hand and avoid a severe burn.

The reflex function of the spinal cord is not only the withdrawal of the hand upon contact with fire. The reflex also includes coughing during illness, closing the eyes during contact with ultraviolet light, and many other uncontrolled defensive reactions. At the same time, a certain segment is responsible for each reflex, and its damage causes the loss of a certain skill.

There is no reflex function the brain does not participate. The reflex itself is a natural protective reaction of the body, which a person is not able to control.

It has been scientifically proven that if reflexes were also processed by the head, human survival rate would be much lower. He would react much more slowly to irritation, which would increase the size of the damage.

Where is the organ located?

Where is the spinal cord located? Such an interesting organ is well protected from mechanical damage. It is located in the spinal canal. Its diameter does not exceed 1 cm. It also contains cerebrospinal fluid, which performs protective functions and creates a favorable environment for functioning. The spinal canal is where the puncture is taken.

Segments

Spinal cord segment –it is a separate part of the organ which is responsible for certain parts of the body, as well as for the functioning of all organs. There are 31 segments in total. To make it easier to understand the functions of each of the segments, which together make up the departments, you need to create a simple table.

Sections of the spinal cord and their functions: table

White and gray matter

This body in general consists of gray and white matter. The gray is surrounded by white and consists of nerve fibers and neuroglia (supporting tissue).

The white matter of the spinal cord is a collection of small bundles of nerves. There are ascending and descending fibers. The first, receiving information from sensitive ones, for example, in the skin, send signals to the head section which processes them.

The processed information passes into descending fibers, which send it to motor cells.

What is it formed by? Gray matter spinal cord? Gray matter is the central part of the organ, which consists of nerve cell bodies.

Important! The gray matter contains 13-14 million nerve cells.

Answering the question: how is the gray matter of the spinal cord formed, it should be said that it is divided into two lateral parts - they are called “butterfly wings”. The “wings” are connected by a central channel 1 mm thick. Each "wing" also consists of three projections (horns).

Structure

The structure of the human spinal cord is as follows. The anterior and posterior grooves “dissect” the organ into two absolutely symmetrical parts in relation to each other. Between these halves is the spinal canal, which contains cerebrospinal fluid. The length of the spinal canal is about 45 cm.

Outer part of the brain consists of the white matter mentioned above, blood vessels, and connective tissue.

Gray matter is distributed in anatomy on the horns:

anterior (transmit impulses to muscles, causing them to move);
lateral (receive information from the skin, muscles, etc.);
posterior (send signals to the brain).

Roots

When considering the functions of the spinal cord and its structure, one cannot fail to mention the so-called spinal cord roots.

In short, the spinal cord roots are bundles of nerve fibers that enter any segment of the organ and form spinal nerves.

The roots form the sensitive part of the spinal nerve. The root consists of motor nerve fibers, which are processes of the anterior horns of the gray matter.

This organ has not yet been fully studied - it still hides many secrets from doctors, and their solution in the future may lead to the cure of currently incurable diseases of the nervous system. Presented to your attention some interesting facts about this amazing organ:

If the spine grows over 20 years, then the spinal cord only grows for 5 years.
Stress leads to a serious decrease in the number of neurons. If the normal number of neurons is 13-14 million, then as a result of stress their number drops by half - this is especially true for pregnant women.
In the process of evolution of vertebrate organisms, the spinal cord appeared first, and only then the brain. The first performed all the simplest functions, including reflex ones.
Some living things are capable of living after brain loss, remaining only with the spinal one.
Damage to a specific area of the organ not only causes loss of sensation below the rupture site, but also the ability to sweat. This forces people with injuries to spend more time in the shadows, as the body has partially lost its thermoregulatory function, which is extremely important for life.
Scientists have not yet come to a general conclusion and cannot establish the mechanism of hair loss throughout the body in humans with spinal cord injuries A.
If the thoracic organ has been affected, the person may lose the ability to cough.
A biopsy and analysis of the white matter of an organ can detect hundreds and thousands of human diseases.
The spinal cord very sensitively senses the rhythm of music, and therefore is automatically able to send signals that will make the body move to the rhythm.
People with a healthy spine are much more active in their sexual life.

So, we figured out the topic: “Spinal cord: structure and functions” and came to the conclusion that this is an organ of vertebrate organisms, which is an intermediate link between the brain and the peripheral nervous system.

Its functions include conductive and reflex. The white matter of the spinal cord, like the gray matter, is part of the organ.

We also found out how the gray matter of the spinal cord is formed.

This organ controls absolutely all motor processes in the body, including contraction of the heart muscles, breathing and movement of the limbs.

Studying the anatomy of the spinal cord

Location of the spinal cord and its functions

Conclusion

Thus, the loss of certain functions, for example, leg movements, makes it possible to determine which part was damaged. Injuries to this organ are among the most serious, and the damage is often irreparable. The main thing is to monitor the health of your spine, and don't overload it without any serious need.

The organ is located in the spinal canal, and its length is no more than 45 cm, which is less than the length of the spine itself. This is due to the fact that the brain grows only until the age of five, and the spine, as a rule, until the end of puberty.

Content

The organ of the central nervous system is the spinal cord, which performs special functions and has a unique structure. It is located in the spinal column, in a special canal, directly connected to the brain. The functions of the organ are conductive and reflex activity; it ensures the functioning of all parts of the body at a given level, transmits impulses and reflexes.

What is the spinal cord

The Latin name for the spinal cord is medulla spinalis. This central organ of the nervous system is located in the spinal canal. The border between it and the brain passes approximately at the intersection of the pyramidal fibers (at the level of the back of the head), although it is conditional. Inside there is a central canal - a cavity protected by the pia mater, arachnoid and dura mater. Between them is cerebrospinal fluid. The epidural space between the outer shell and the bone is filled with fatty tissue and a network of veins.

Structure

The segmental organization distinguishes the structure of the human spinal cord from other organs. This serves for communication with the periphery and reflex activity. The organ is located inside the spinal canal from the first cervical vertebra to the second lumbar vertebra, maintaining the curvature. From above it begins with an oblong section - at the level of the back of the head, and below - it ends with a conical point, a terminal thread of connective tissue.

The organ is characterized by longitudinal segmentation and the significance of its links: the anterior root filaments (axons of nerve cells) emerge from the anterolateral groove, forming the anterior motor root, which serves to transmit motor impulses. The posterior radicular filaments form the dorsal root, conducting impulses from the periphery to the center. The lateral horns are equipped with motor, sensory centers. The roots create the spinal nerve.

Length

In an adult, the organ is 40-45 cm in length, 1-1.5 cm in width, weighing 35 g. It increases in thickness from bottom to top, reaching its greatest diameter in the upper cervical region (up to 1.5 cm) and lower lumbar region. sacral (up to 1.2 cm). In the chest area the diameter is 1 cm. The organ has four surfaces:

flattened anterior;
convex back;
two rounded side ones.

Appearance

On the anterior surface along the entire length there is a median fissure, which has a fold of the meninges - the intermediate cervical septum. At the back there is a median groove connected to a plate of glial tissue. These slits divide the spinal column into two halves, connected by a narrow bridge of tissue, in the center of which is the central canal. There are also grooves on the sides - anterolateral and posterolateral.

Spinal cord segments

The sections of the spinal cord are divided into five parts, the significance of which depends not on the location, but on the section in which the exiting nerves leave the spinal canal. In total, a person can have 31-33 segments, five parts:

cervical part – 8 segments, at its level there is more gray matter;
chest – 12;
lumbar – 5, the second region with a large amount of gray matter;
sacral – 5;
coccygeal – 1-3.

Gray and white matter

A section of the symmetrical halves reveals a deep median fissure, a connective tissue septum. The inner part is darker - this is the gray matter, and the periphery is lighter - the white matter. In cross-section, the gray matter is represented by a “butterfly” pattern, and its protrusions resemble horns (anterior ventral, posterior dorsal, lateral lateral). Most gray matter is in the lumbar region, less in the thoracic region. The entire surface of the conus medullaris is gray, and along the periphery there is a narrow layer of white.

Functions of gray matter

How is the gray matter of the spinal cord formed? It consists of nerve cell bodies with processes without a myelin sheath, thin myelin fibers, and neuroglia. The basis is multipolar neurons. Cells lie inside in groups called nuclei:

radicular - axons leave as part of the anterior roots;
internal - their processes end in synapses;
fascicular - axons pass to the white matter, carry nerve impulses, and form pathways.

Between the posterior and lateral horns, the gray protrudes in strands into the white, forming a network-like loosening - a reticular formation. The functions of the gray matter of the central nervous system are: transmission of pain impulses, information about temperature sensitivity, closure of reflex arcs, receiving data from muscles, tendons and ligaments. Neurons of the anterior horns are involved in the communication of departments.

White matter functions

A complex system of myelinated, unmyelinated nerve fibers is the white matter of the spinal cord. It includes supporting nervous tissue - neuroglia, plus blood vessels, and a small amount of connective tissue. The fibers are collected in bundles that provide connections between segments. White matter surrounds the gray matter, conducts nerve impulses, and performs mediating activities.

Functions of the spinal cord

The structure and functions of the spinal cord are directly related. There are two important tasks of the organ’s work: reflex and conduction. The first is to perform the simplest reflexes (withdrawing a hand when burned, straightening joints), connections with skeletal muscles. The conduction transmits impulses from the spinal cord to the brain, back along the ascending and descending pathways.

Reflex

The response of the nervous system to irritation consists of a reflex function. This includes withdrawing the hand when receiving an injection, coughing when foreign particles enter the throat. Irritation from the receptors is impulsed into the spinal canal, switches motor neurons that are responsible for the muscles, causing them to contract. This is a simplified diagram of a reflex ring (arc) without the participation of the brain (a person does not think when performing an action).

Reflexes are classified as congenital (breast sucking, breathing) or acquired. The former help to identify the correct operation of the arch elements and organ segments. They are checked during a neurological examination. The knee, abdominal, and plantar reflexes are mandatory for checking a person’s health. These are superficial types; deep reflexes include flexion-elbow, knee, and Achilles.

Conductor

The second function of the spinal cord is conductive, which transmits impulses from the skin, mucous membranes and internal organs to the brain, in the opposite direction. White matter serves as a conductor, carries information, an impulse about external influences. Due to this, a person receives a certain sensation (a soft, smooth, slippery object). If sensitivity is lost, sensations from touching something cannot be formed. In addition to commands, impulses transmit data about the position of the body in space, pain, and muscle tension.

Which human organs control the functioning of the spinal cord?

The main organ of the central nervous system, the brain, is responsible for the spinal canal and control of the entire functioning of the spinal cord. Numerous nerves and blood vessels act as assistants. The brain has a great influence on the activity of the spinal cord - it controls walking, running, and labor movements. When communication between organs is lost, a person ultimately becomes practically helpless.

Risk of damage and injury

The spinal cord connects all body systems. Its structure plays an important role in the proper functioning of the musculoskeletal system. If it is damaged, a spinal injury will occur, the severity of which depends on the extent of the damage: sprains, ligament ruptures, dislocations, damage to discs, vertebrae, processes - mild, moderate. Severe fractures include displaced fractures and multiple injuries to the canal itself. This is very dangerous, leading to impaired functionality of the cords and paralysis of the lower extremities (spinal shock).

If the injury is severe, shock lasts from several hours to months. The pathology is accompanied by impaired sensitivity below the site of injury and dysfunction of the pelvic organs, including urinary incontinence. Computed resonance imaging can detect injuries. To treat minor bruises and damaged areas, medications, therapeutic exercises, massage, and physiotherapy can be used.

Severe variants require surgery, especially to diagnose compression (rupture - cells die instantly, there is a risk of disability). The consequences of spinal cord injury are a long recovery period (1-2 years), which can be accelerated by acupuncture, occupational therapy and other interventions. After a severe case, there is a risk of not fully regaining motor ability, and sometimes of remaining in a wheelchair forever.

Video

Attention! The information presented in the article is for informational purposes only. The materials in the article do not encourage self-treatment. Only a qualified doctor can make a diagnosis and make recommendations for treatment based on the individual characteristics of a particular patient.

Found an error in the text? Select it, press Ctrl + Enter and we will fix everything!