Nervous System Pain

The Nervous System

The nervous system has many components and is best reviewed by identifying each structure. Please scroll down to review the various components of the brain or follow each hyperlink to a specific structure.

The nerve cell

Nerve_Tissue

Nerve_fibers_

Supporting_Nerve_Tissue_

Synapses_

The_nervous_system_and_its_organs

The_central_nervous_system

The_brain_(cerebrum)

The_cerebrum_(telencephalon)

The_brain_stem_(truncus_cerebri)

Diencephalon

Rhombencephalon_(rhombencephalon)

The_cerebellum_(cerebellum)

The_cerebral_cortex_centers

The cerebral ventricles

The extrapyramidal system

The basal ganglia

The_reticulum_(formatio_reticularis)

The hypothalamus

Pituitary_gland_(hypophysis)

The pineal gland

The Nerve Cell (Neuron)

The structure of a nerve cell.

the structure of a nerve cell
The nerve cells (the neurons) are the building blocks of the nervous systems. They are units that function independently and there are up to 25 billion of them in the human brain alone. They are connected with one another through so-called synapses and they are interwoven through their branches with the branches of other nerve cells and sensory cells forming chains of neurons.

The shape of the neurons is irregular and they also differ in size, although the basic form is uniform. Each nerve cell consists of three sections: the cell body (pericaryon) with the actual nucleus as the center of metabolism and the cellular branches called dendrites and neurites (axons).

Dendrites are extended twig-shaped processes that receive stimulation from nerve cells connected to them through special contacts (synapses) and pass them on to the cell body. This stimulation is sent to another nerve cell or to an effector organ (for instance, the skeletal muscle) from here through a neurite. This stimulus is transmitted in the synapses with the aid of transmitters, i.e. chemical carriers.

In contrast to the extended processes of the dendrites, axons (neurites) are structured in such a way that they may be a few millimeters to one meter long. For instance, if we stub our toes, the feeling of pain is brought by one single axon all the way to the lower spinal cord! Surrounded by what is known as a myelin membrane with constrictions at certain intervals, the stimulus can be conducted especially fast jumping from one constriction to another.

We differentiate between unipolar, bipolar, pseudounipolar and multipolar nerve cells depending upon how frequently the axon processes occur and how much they branch out.

The pericaryon (cell body) not only contains the nucleus, but also some organelles such as ribosomes, mitochondria, rough endoplasmic reticulum and caniculus for transporting substances to the synapses.

Please click on the image below for a video on nerves.

Nerve Tissue

Nerve tissue is the module of the nervous system. It is the most highly developed tissue in the human body. Its function is to pass on and process stimuli from the body or the environment.

Our brain is a fascinating organ, and that is what makes dealing with anatomy and physiology of nerve tissue so interesting. Up to just a few years ago, people believed that differentiated knowledge of the nerve cells and its links would lead to deeper insight into the higher functions of the brain, such as memory or emotions. This was a mistake. At present, we know certain things about conducting stimuli and switching points in the nervous system. However, we do not know everything about what happens in the brain.

As other organs, nerve tissue consists of individual cells. Here we differentiate between nerve cells and glia cells.

Nerve cells are responsible for taking in stimuli, conducting and processing them. The glia cells are something like connective tissue for the nerves. They support and feed the nerve cells and they also defend and insulate the nerve fibers. This means that they are indirectly involved in conducting stimuli.

Nerve tissue using the example of the brain cell.

nerve tissue using the example of the brain cell

The structure of the supporting nerve tissues.

Nerve fibers

The human nerve cells are stimulated along the surface of the nerve cell appendix (dendrite or axon). For this reason, each nerve cell appendix must be insulated from its neighbors. To this end, the nerves are cased in nerve sheaths (neurilemma).

The term nerve fiber refers to a nerve cell appendix, cased in a nerve sheath. Nerve fibers can be divided up into medullated and non-medullated fibers.

Medullated nerve fibers are well insulated. The medullary sheath cell (Schwann's cell) spirals its cell body around the nerve cell appendix. Where two nerve sheath cells meet, the medullary sheath is indented all the way around (constriction ring).

Stimulation of a nerve fiber jumps from constriction ring to constriction ring. The thicker the fiber, the larger the gaps between constriction rings and the faster the stimulation is transported. The nerve fibers are classified according to their performance: ''A" nerve fibers (20 - 100 m/s = 66 -330ft/s), "B" nerve fibers (10 m/s = 33 ft/s) and "C" nerve fibers (1 m/s = 3.3ft/s).

Non-medullated nerve fibers are not as well insulated. They are often to be found together with other nerve fibers within the cell body of the medullary sheath cell, neither bound nor constricted. Stimulation is much slower in this case. Non-medullated nerve fibers are primarily to be found in the vegetative nervous system.

Depending on the direction of stimulation, a distinction is made between afferent and efferent nerve fibers. Afferent nerve fibers conduct stimulations from the periphery of the body towards the central nervous system (or within the central nervous system from lower to higher centers), whereas efferent nerve fibers run in the reverse direction.

The structure of a nerve fiber.

Supporting Nerve Tissue

Apart from the nerve cells, the nerve tissue consists of what is known as Glia cells, which are a module of the nervous system. They form the supporting and nutrition tissue for the nerve cells. At the same time, they defend and insulate nerve fibers. Glia cells are therefore also indirectly involved in conducting stimuli.

The cells are capable of splitting, and they retain this ability throughout their life. They therefore act as a replacement for nerve cells (dendrite and axion) that are no longer intact because of a lack of oxygen or injury.

Glia cells have the same histogenetic origin as the nerve cells themselves. They have a cell body, which produces cell processes. In the cellular fluid and the processes, there are so-called Glia fibrillas or Glia filaments as forming structures.

There are a variety of cell types within the central nervous system and peripheral nervous system, depending upon their type.

The Central Nervous System

Here the ependym cells line the cavities in the brain and spinal cord. Astrocytes have a supporting function. They are star-shaped and have a number of processes. If nerve tissue is injured, they can form a maculate replacement. Oligodendrocytes for the medullar sheaths (which function as electrical insulation) are also to be found in the white matter (substantia alba) of the spinal cord. Microglia cells are the defense cells (phagocytosis) in the central nervous system. There are also cells that produce the fluid of the brain and spinal cord (liquor cerebrospinalis).

The Peripheral Nervous System

The satellite cells surround the nerve cells around the spinal cord and cranial nerve ganglia. Schwann's cells form the myelin sheaths here and special supporting cells (gliocytus terminalis) are on the nerve endings and motor end-plate.

The structure of the supporting nerve tissues

Synapses

Synapses are the contact points of a nerve process with a nerve, muscle or glandular cell. Information is transmitted to other cells through them and they are something like the switching point.

Generally, a synapse connects the axon (nerve process) of a nerve cell with the dendrites (nerve process) of another nerve cell. We designate the connection between the axon and a muscle cell a motor end-plate.

A synapse essentially consists of three parts. The one part is the presynaptic neuron, which contains the vesicle with a chemical transmitting substance (the transmitter). The other part is the connecting post-synaptic cell with a membrane that contains the receptors for the transmitter substance. There is a tiny gap between the two (the synaptic gap), through which the membrane of the post-synaptic cell is stimulated or inhibited by transmitter.

Impulses are only passed on in one direction in synapses. The more frequently they are used, the better they function (for instance, the learning and memory function). Furthermore, synapses are places where numerous medicines take effect.

Synapses within the nerve tissue.

The nervous system and its organs

The human nervous system connects the whole body to its brain (cerebrum), the principal control center. In this way, all procedures in the body are controlled and sensibly coordinated.

Stimuli originating from outside or within the body itself are sent to the spinal medulla (medulla spinalis) and the brain. Here the stimuli are processed and the response commands are sent out to the tissues and organs.

The nervous system is divided into the central nervous system with spinal medulla and brain, the peripheral nervous system, including all nerves, which connect the central nervous system and the body periphery (e.g. sensory organs, muscles) and the vegetative nervous system with sympathetic and parasympathetic nervous system.

components of the central nervous system

The central nervous system

In the human body, the nerve cells accumulate in a central location to form the brain (cerebrum) and spinal medulla (medulla spinalis). Nerve processes run from this central location in tracts to the edge (periphery) of the nervous system.

The brain and spinal medulla constitute the central nervous system. Here, signals received from the peripheral nervous system are analyzed and memorized, and voluntary motor signals are built up.

This performance required of the brain is highly complicated and requires countless nerve cells. The principle activities of the nervous system are performed in the cerebral cortex (cortex cerebri). This is the central location for thinking, for the will and for emotions, i.e. the headquarters for all bodily functions. The cerebral cortex is responsible for our attitudes regarding the environment, good and bad, right and wrong, beautiful and ugly.

A large vascular network supplies oxygen and nutrients to the central nervous system. It is embedded in body cavities, consisting of the skullcap in the head and the vertebral arches (arcus vertebrales) in the neck and trunk. They protect the brain and the spinal medulla.

Internally, this protection is reinforced by three layers of connective tissue, which surround the brain in the head as meninges, and also surround the spinal medulla in the spinal column (columna vertebralis). Between the middle and inner layer there is a space, which is filled with cerebral and spinal fluid (liquor). This fluid provides the central nervous system with extensive protection from mechanical damage.

An overview of the central nervous system

an overview of the central nervous system

The brain (cerebrum)

It is the brain that distinguishes humans from other living creatures. It allows us to act deliberately and think logically. It is the central management for all our thoughts, control center for practically every movement, the source of all our feelings and emotions, and equally responsible for conscious and unconscious actions.

The brain of an adult weighs between 1200 and 1500 g. The idea that the weight has some sort of correlation to intelligence is completely wrong. Compared to other living creatures, we certainly do not have the largest brain, either in absolute terms (elephant approx. 5000 g) or in relative terms in relation to body weight – a sparrow's brain is larger.

The brain is divided into four main sections: cerebrum (cerebrum), brain stem (truncus cerebri), diencephalon (diencephalon) and cerebellum (cerebellum). From an anatomical point of view, the essential difference between man and other vertebrates is in the cerebrum, which accounts for most of the human brain.

The cerebrum controls our deliberate actions and is also the center of intelligence, learning and teaching ability, memory, will and feelings. The cerebellum coordinates our movements, is responsible for balance and orientation in space. The brain stem controls among others respiration, blood circulation, sleeping/waking rhythm and our attention, and is directly or indirectly connected to all parts of the central nervous system.

The brain, which belongs to the central nervous system (or CNS), is protected, just like the spinal medulla (medulla spinalis), by a bony capsule (here the skullcap), and, similar to the spinal medulla, it is enclosed by meninges (meninges) that envelop the brain and the brain fluid (liquor cerebrospinalis), and work like padding.

The CNS is therefore protected mechanically on all sides both in the spinal medulla and in the brain itself by a bony layer, a layer of connective tissue and a layer of fluid in between.

The two thick bundles of nerve fibers, which connect the brain to the body muscles, are called pyramids or pyramidal tracts. At the so-called pyramidal decussation, the transition point from spinal medulla to the medulla oblongata, most of the fibers change side. This means that the left half of the brain controls motor response in the right side of the body, and the right half of the brain in the left side of the body. The pyramid can be detected with the naked eye as far as the Varolius bridge.

Please click on the image below for a video on the structure of the brain.

Please click on the image below for a 3D image of the brain.

Sections of the brain

sections of the brain

X-ray photograph of the cranium enclosing the brain

X-ray photograph: the cranium encloses the brain

CT scan image of the brain

the brain structures in the tomogram

The position of the pyramid

the position of the pyramid

The structure of the pyramid

the structure of the pyramid

The cerebrum (telencephalon)

The cerebrum forms a hood-like cover over the diencephalon (diencephalon). It consists of two halves (hemispheres) divided by a deep fissure (fissura longitudinalis cerebralis). They are connected by a thick nerve tract (corpus callosum), the so-called corpus callosum.

As in the cerebellum (cerebellum), the surface of the hemispheres consists of furrows (sulci) and coils (gyri), which increase the surface area and are divided into primary, secondary and tertiary furrows. The primary furrows in all brains have the same structure, and the secondary furrows vary only slightly, whereas the tertiary furrows are different in every brain. They make every single brain individual, and are unmistakable.

As far as the outer structure is concerned (morphological structure) all brains have five different main areas in each hemisphere, although these can differ in individual extent. These are the frontal lobe (lobus frontalis), parietal lobe (lobus parietalis), temporal lobe (lobus temporalis), occipital lobe (lobus occipitalis) and insular lobe (lobus insularis). These designations are important for localizing the areas of the cerebral cortex (cortex cerebralis), which make up our personality.

The cortex areas perform different achievements, for example the occipital lobe accommodates the visual center, the temporal lobe the auditory center, the parietal lobe has the centers for sensory impressions and sensitivity.

The frontal lobe contains the motor centers and something that makes us different from all other living creatures and constitutes our own personality structure: consciousness, creativity, responsibility and conscience are accommodated in this area of the brain which is still not properly researched. They constitute the "ego" and our idea of "the others".

The cerebral cortex (cortex cerebralis) refers to the gray matter on the surface of the cerebrum (cerebrum), in contrast to the gray matter in the depth of the cerebral medulla, the so-called basal ganglia. This phrase is somewhat vague. Some use this to refer only to the striated body (corpus striatum) of the cerebrum; others also include the amygdaloidal body (corpus amygdaloideum), part of the rhinocephalon, together with the thalamus (thalamus).

The human cerebral cortex is about 1.5 – 4 mm thick. Its total surface amounts to about 0.2 m² and contains approximately 10 billion neurons.

The part of the cerebrum bordering on the basal ganglia is the insular lobe. It lies deep in the lateral cerebral furrow and has been covered during its development by parts of the cerebrum growing at a faster rate (frontal lobe, parietal lobe and temporal lobes).

From a functional point of view, the insular lobe is connected to the limbic system.

Please click on the image for an animation of the brain coordinating movement.

Please click on the image to view an animation on the function and positions of the cerebrums.

Structure of the lobes of the brain

structure of the lobes of the brain

The brain stem (truncus cerebri)

The brain stem is anatomically divided into the mesencephalon (mesencephalon), pons (pons) and medulla oblongata (medulla oblongata). The cerebellum (cerebellum) and diencephalon (diencephalon) also share the same development history The brain stem constitutes the lower, oldest part of the brain. It opens into the diencephalon, which in turn is covered by the cerebrum (cerebrum) like a hood.

The medulla oblongata constitutes the transition of the spinal medulla into the brain. Its structure still resembles the spinal medulla. It contains the reflex centers for chewing, swallowing, saliva flow and the protective reflexes, e.g. sneezing and coughing.

The nerves in the pyramid tract cross underneath the pons and accommodate among others the control centers for the automatic procedures involved in the heartbeat, respiration and metabolism.

The subsequent pons is the changeover point for the descending (efferent) cerebrum tracts, which change over to fibers here and lead to the cerebellum.

The mesencephalon (a brain section 1.5 cm wide) above the pons opens into the diencephalon. It is the central control point for automatic movements, such as rotation around the body axis and erecting the head and body, and also accommodates the visual and auditory systems together with the so-called red and black nucleus.

Of the twelve main pairs of nerves originating in the brain, ten go directly to the brain stem (III-XII). The cranial nerves are numbered with Roman numerals according to the sequence of leaving the brain.

There is a network of nerve cells called the reticulum (formatio reticularis = reticulum) covering the whole length of the brain stem with some cell accumulations, referred to as nuclei

These nucleus areas, so-called brain stem nuclei, are controlled on the one hand by the cerebrum, and assume on the other hand the functions attributed to the spinal medulla, such as monitoring the sleeping/waking rhythm and attention, and allow our body to respond to the many stimuli it receives.

An extrapyramidal motor nucleus area on the side next to the pyramid at the end of the medulla oblongata under the pons is called the olive or olivary nucleus.

The formatio reticularis is also part of the extrapyramidal motor system and thus shares responsibility for muscle tone and reflex excitability.

Structure of the brain stem

structure and structure of the brain stem area

The diencephalon (diencephalon)

The diencephalon lies between the mesencephalon and the telencephalon (Telencephalon = cerebrum). The diencephalon has four sections: epithalamus, dorsal thalamus, subthalamus and hypothalamus.

The hypothalamus is of special significance for controlling the vegetative nervous system, being its principle regulation center. The hypothalamus itself is controlled by the limbic system.

The hypothalamus controls for example important functions, such as the balance of water, heat and energy in our body. It regulates the circulatory system, controls the ovarian cycle and birth contractions, and is involved in controlling sleep. It also produces hormones with which it controls the pituitary gland (hypophysis).

The thalamus is the end point for all sensitive and sensory tracts. Here they are transferred to the corresponding fiber systems and sent on to the cerebrum.

The epithalamus is an appendix of the thalamus and controls the olfactory center (olfactory center), brain stem and pineal gland (epiphysis).

The subthalmus is the motor zone of the diencephalon and belongs to the extrapyramidal motor system.

The location and structure of the diencephalon.

the location and structure of the diencephalon

Rhombencephalon (rhombencephalon)

The rhombencephalon is located in the posterior cranial fossa or rhombic fossa (so-called because of its shape). It consists of the cerebellum (cerebellum), the pons (pons) and the medulla oblongata (medulla oblongata).

The cerebellum practically forms the roof with the pons and medulla oblongata forming the lower part; the medulla oblongata is practically vertical and continues essentially in the direction of the spinal medulla (curving slightly to the front).

cerebellum, bridge and extended medulla: rhombencephalon

The cerebellum (cerebellum)

The cerebellum is joined to the cerebrum at the back of the head. It practically composes the roof of the rhombocephalon. It is connected to the mesencephalon by a front stalk, to the pons by a middle stalk and to the medulla oblongata by a rear (lower) stalk. It is connected to all sections of the central nervous system by pathways.

The coils (gyri) and furrows (sulci) of the cerebellum are much finer than in the cerebrum. They have a leaf-shaped appearance and serve to increase the cortex surface. Analog to the cerebrum, the cerebellum is divided into two hemispheres, a middle section is called the cerebellum vermis. Recent medicine sees the cerebellum as part of the motor system. It has close connections to the system of balance, to the basal motor nuclei (red and black nucleus, olivary nucleus, subthalamus, etc.) and to the cerebral cortex (cortex cerebri).

The cerebellum has a gray cortex on the outside (cortex cerebelli), followed by a white medullar bed with four important nuclear areas (nuclei cerebellares). The most important of these nuclei is the dentate nucleus (nucleus dentatus). Its name comes from one extreme pleat and it is related to the red nucleus (nucleus ruber) already mentioned above, and to the thalamus.

The tasks of the cerebrum including maintaining/controlling balance and thus orientation in space, coordination of our movements in time, coordination of the interaction between individual muscles, and regulation of muscle tension (muscle tone).

Please click on the image for an animation on the position and function of the cerebellum.

The location and structure of the cerebellum.

the location and structure of the cerebellum

The structure of the cerebellum from above.

the structure of the cerebellum from above

The cerebral cortex centers

The human cerebral cortex contains large numbers of different neurons (nerve cell + process) whose exact interactions are still not properly clarified. They are arranged in 6 layers.

In order to increase the surface area while retaining the same brain volume, the cerebral cortex has a folded structure caused by furrows (sulci) and coils (gyri). The functions of some cortex areas are known, for example the front central coil of the brain (gyrus praecentralis) is responsible for performing voluntary movements (center for motor muscle movement).

The sensory center lies in the coil behind the central furrow (sulcus centralis). This is where deliberate sensations take place. The center for conscious vision is on the inside of the two occipital lobes. Transverse coils of the temporal lobe accommodate the auditory center.

When certain areas of the cerebral cortex (cortex cerebri) are damaged, part of their functions is lost. In lower mammals the cerebral cortex is less well developed. The surface area does not have so many folds and is thus much smaller. Here it is practically only responsible for olfactory impressions; sensitive and sensory excitation is controlled by the thalamus (part of the diencephalon). The basal ganglia are responsible for motor processes.

Please click on the image for an animation of the body controlled by impulses.

The cerebral ventricles

Deep inside the brain (cerebrum) there are several connected ventricles in the so-called ventricle system, which produce and circulate a fluid as clear as water, the brain fluid (liquor cerebrospinalis). This is also called nerve or spinal fluid.

Each half of the brain (hemisphere) has one lateral ventricle. It consists of a front horn (cornu anterius) in the frontal lobe, a central section (pars centralis) in the frontal and parietal lobes, a rear horn (cornu posterius) and a lower horn (cornu inferius), which extends into the temporal lobe.

Each lateral ventricle, a III ventricle (diencephalon) and a IV ventricle (under the cerebellum) has a venous plexus. Here (in the plexus chorideus) the brain fluid is produced and brought to the ventricles by diffusion and active transport.

From the lateral ventricles the fluid reaches the III ventricle between the walls of the left and right diencephalon (diencephalon). It is then transported via a canal (aquaductus cerebri) in the mesencephalon (mesencephalon) to the IV ventricle, where it flows through three openings into the outer fluid spaces (subarachnoid space).

So the brain fluid fills the cavities of the brain (cerebrum) and also the central canal of the spinal medulla (medulla spinalis). If we bang our head against a wall, this produces a bump but the brain does not immediately hit a skull bone but lies protected in the brain fluid, which intercepts the impact.

The position of the ventricles of the brain.

the position of the ventricles of the brain

The meninges (meninges)

The brain is surrounded by three meninges: the outer hard meninges, the arachnoid membrane and the inner meninges.

The outer hard meninges (dura mater encephali) is fastened to the inside of the scull and consists of taut collagen connective tissue. The meningeal artery runs between the skullcap and the hard meninges.

The so-called arachnoid membrane (arachnoide mater encephali) has grown together with the dura and consists of delicate connective tissue with few blood vessels. It covers both hemispheres without adapting to their surfaces. The resulting spaces contain the brain fluid (liquor cerebrospinalis), which nourishes the brain, is responsible for uniform distribution of pressure and for protecting the brain (fluid padding).

In contrast to the arachnoid membrane, the inner meninges (pia mater encephali) follows all uneven areas and furrows (sulci). The inner meninges consists of a very firm connective tissue and contains the blood vessels of the brain.

The meninges in the area of the telencephalon.

meniges in the area of the telencephalon

The cranial nerves

12 cranial nerves depart from every hemisphere. These are numbered with Roman numerals from the front (rostral) to the back (dorsal) and from top (cranial) to bottom (caudal).

All Latin expressions used below are preceded by the word nervus = nerve, abbreviated N.

I Olfactory nerve (n. olfactorius)II Optical nerve (n. opticus)III Oculogyration nerve (n. oculomotorius)IV Trochlear nerve (n. trochlearis)V Trigeminal nerve (n. trigeminus)VI Abducent nerve (n. abducens) VII Facial nerve (n. facialis)VIII Vestibulocochlear nerve (n. vestibulocochlearis)IX Glossopharyngeal nerve (n. glossopharyngeus)X Visceral nerve (n. vagus)XI Accessori nerve (n. accessorius)XII Hyploglossal nerve (n. hypoglossus)

The position of the main nerve pairs.

the position of the main nerve pairs

The limbic system

The cerebrum and brain stem are connected by a large number of nerve cells (neurons) and nerve tracts. Together they make up a communications system, which is cohesive in terms of function but morphologically is located in many different places.

Anatomically, the limbic system includes parts of the cerebrum (cerebrum), the diencephalon (diencephalon) and the mesencephalon (mesencephalon).

Among others, the limbic system controls the hypothalamus and is responsible for our emotional reactions to external factors influencing us. The limbic system influences certain regions of the central nervous system by individual reactions (according to personality and constitution).

It filters incoming information from the environment and from inside the body, evaluates the information and memorizes it, and arranges for the selected areas of the central nervous system to send corresponding pulses to the peripheral organs and limbs (afferent and efferent tracts).

Not without reason, the limbic system is also called the "emotional brain", as it is responsible for all our feelings and their physical revelations in the body.

It is the central control for learning and forgetting, for horror, anger and ecstasy, for sweating and shivering, for flushing and going pale, for laughing and crying, lust and frustration, hunger and thirst, for feeling sheltered and equally for hostility, hatred and our sexual behavior.

The structure of the limbic system.

diagrammatic the structure of the limbic system

The insular lobe (lobus insularis)

The insular lobe is part of the cerebrum adjoining the basal ganglia. It is located in the depths of the lateral cerebral furrow and during its development it has been covered by faster growing areas of the cerebrum (frontal, parietal and temporal lobes).

In terms of functions, the insular lobe is related to the limbic system.

The deep insular lobes as a component of the cerebrum.

the deep insular lobes as a component of the cerebrum

The extrapyramidal system

The extrapyramidal motor system, or EPS for short, derives its name from the fact that its tracts lie outside the pyramid tract. It controls, among others, automatic (involuntary) movements and regulates muscle tone.

The EPS also controls the position of the body and its extremities in space (spatial feeling). It gives our movements a "personal touch" (facial expression, kind of movements, associated movements etc.,) so that it is also referred to as the "motor memory".

Structures belonging to the EPS include for example the basal ganglia in the cerebrum, the subthalamus in the diencephalon, the red and black nucleus in the mesencephalon, the olivary nucleus in the medulla oblongata, and parts of the pons (pons), the cerebellum (cerebellum) and the reticulum (formatio reticularis).

The basal ganglia are a group of control structures beneath the insular lobe, consisting of a central collection of gray matter (nuclei) equipped with an extremely complex network of links and connections. Knowledge about the significance of the basal ganglia is still very incomplete, but they would appear to be responsible for motor movements and muscle tone.

Even the smallest malfunctions in one of the areas concerned can confuse the entire EPS.

The structure of the extrapyramidal system.

the structure of the extrapyramidal system

The basal ganglia

The basal ganglia are another group of control centers underneath the insular lobe, consisting of a centrally located accumulation of gray matter (nuclei) and equipped with an extremely complicated network of links and connections.

Knowledge about the significance of the basal ganglia is still very incomplete, but they would appear to be responsible for motor movements and muscle tone.

In terms of their functions they belong to the extrapyramidal motor system.

The position of the basal ganglia.

the position of the basal ganglia

The reticulum (formatio reticularis)

The reticulum refers to groups of nerve cells and the corresponding short fascicule of fibers lying between the otherwise clearly differentiated tracts and nuclei. These are usually smaller groups of cells; some examples of the larger cell collections belonging to the formatio reticularis include:

· red nucleus (nucleus ruber)· black nucleus (substantia nigra)The reticulum occurs in the brain stem, diencephalon, medulla oblongata and in the spinal medulla. It coordinates the cranial nerves and adjusts their activity in line with other parts of the central nervous system. This is why it is also frequently referred to as our central consciousness.
The many nerve stimuli (electrical signals) reaching the reticulum in every moment are sorted, interpreted, filtered and where applicable memorized here. The reticulum (formatio reticularis) ensures that only "important" information is passed on to the cerebrum and thus to our consciousness.
In most cases, the reticulum triggers subconscious reactions. It is also an important component of the ascending reticular activation system (ARAS), the "alarm system" of our body.
All signals sent by the ARAS penetrate our consciousness with top priority (sounding horns, screams, smell of fire, etc.). Vice versa, via the ARAS our consciousness can also guide all our attention (concentration) to one single activity, a mechanism that allows us to produce top sporting and mental performance.

Network substance within the extrapyramidal system.

network substance within the extrapyramidal system

The hypothalamus

The hypothalamus is part of the diencephalon (diencephalon). It is responsible for coordination of the vegetative nervous system and the endocrine system for regulating the preservation of the human organism, its reproduction and its willingness to work.

The hypothalamus is located within the diencephalons below the thalamus. There are two important nuclei within the hypothalamus (nucleus supraopticus and nucleus paraventricularis), consisting of accumulations of nerve cells. They are capable of producing hormones, which travel along the nerve paths to the pituitary gland, where they are stored. These two hormones are the adiuretic hormone (ADH) and oxytocin.

The task of the hypothalamus is to control body temperature, to control food intake and to regulate the balance of water in the body. It also helps to regulate the cardiovascular system, controls the ovarian cycle and labor contractions and is involved in controlling sleep. It is also responsible for feelings and has control of the vegetative nervous system. The hypothalamus itself in turn is controlled by the limbic system.

After believing for a long time that the pituitary gland was the only regulation center for the hormone system, we know today that there is a close link between the hypothalamus and the pituitary gland. The pituitary gland is controlled by the hypothalamus (transport of hormones from the hypothalamus to the pituitary gland via capillaries and nerve paths, i.e. instructions are passed on by means of the body humors and the autonomous nervous system).

The position of the hypothalamus.

the position of the hypothalamus

Pituitary gland (hypophysis)

The pituitary gland, as a part of the endocrine system, controls, by secretion of the corresponding hormones, among other things, our growth and sexual behavior.

Together with the pineal gland, it is some kind of a clock for certain rhythms of life, such as the rhythms of the moon, the days and the weeks.

The hypophysis is subject to the control of the hypothalamus to which it is connected, and is, morphologically, a part of the interbrain.

Please click on the image below for an animation of the pituitary gland.

The position and structure of the hypothalamus.

the position and structure of the hypothalamus

The pineal gland (epiphyse / corpus pineale)

The pineal gland is located in the rear upper section of the diencephalon (diencephalon).
It is about 12 mm long and cone-shaped. It is connected to the brain by means of stalks, the habenulae. Earlier centuries used to presume that this was where the soul lived.

The fine structure is seen to contain numerous vessels and connective tissues within a lobe structure. With increasing age the pineal gland degenerates, and there is calcification and cyst formation. It can therefore be taken as orientation aid in X-rays of the head.

The function of the pineal gland is not fully researched. One of its functions is to produce melatonin, which, as the counterpart to intermedin (pituitary hormone), prevents pigmentation. The production of melatonin depends on the light and in some cases also on the time of the year.

In morphological terms, the pineal gland belongs to the epithalamus and thus to the diecephalon (diencephalon).

Please click on the image below for an animation of the pineal gland.