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The brain is the most important of the human organs. The human brain performs many complex functions, so it is not awakening to know how complex the structure of the brain is. Basically, there are three parts of the brain: the brain proper, the dumbrain and the brainstem - each of them differs in structure and function.

Brain , or actually, to use more correct terminology -brain , is one of the most important and having the most complex structure of human organs. In Latin it is referred to as " encephalon ", this word is derived from the Greek wordsen , which means "in" or "inside", and fromkephalostranslated as "head". Together, the brain and the spinal cord form thecentral nervous system . It is in the structures of the brain that the course of various life processes, such as breathing and heart function, is controlled. Before we perform any activity, many different centers are activated in the brain - all this is done in order for the body to properly perform the planned activity.Brain mass and volume.Brains may differ from person to person. in terms of parameters such as weight and volume. Overall, however, it is estimated that the average weight of the human brain ranges from1200 to 1400 grams , but its average volume varies depending on gender - the female brain is usually around1100 centimeters. cubic , the volume of this organ in men is typically around1,250 cubic centimeters .

The brain does not have such a mass at the time of birth - in an infant the average weight of the brain is about 300 g, therefore it is clearly visible that brain development occurs not only in the prenatal period, but also after birth In theory, it would seem that the larger a person's brain, the greater hisintelligence . Opinions on this are divided, but the prevailing opinion is that there is really no relationship between the mass or volume of the brain and intelligence. There are generally four main parts of the brain:

  • brain,
  • interbrain,
  • brainstem,
  • cerebellum.

Each of them has a different structure, but also different functions.

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Brain structure: brain

In medical terminology, the brain ( cerebrum ) is the largest part of the entire brain, which isthe two hemispheres of the brain . They are separated from each other by a longitudinal fissure, but this does not mean that the cerebral hemispheres are not in contact with each other - the connection between them is provided by nerve fibers located in the great commissure (also called the corpus callosum).

Theoretically, at first glance, the cerebral hemispheres are constructed symmetrically, but functionally in humans, typicallyis dominated by one of the hemispheresof the brain. The outer part of the hemispheres of the brain is the cortex of the brain composed of gray matter , in which the bodies of nerve cells (neurons) are located. Under the gray matter there iswhite matter , consisting of fibers (axons) of nerve cells.

The surface of the brain is heavily folded, so that on the same surface it is possible to have much more nerve cells than if this part of the brain was completely smooth. Within the hemispheres of the brain, there are gyruses and fissures. Both hemispheres of the brain can also be divided into lobes. Moving from the front to the rear, the following brain lobes are listed:

  • frontal
  • parietal
  • temporal
  • occipital
  • marginal (also known as limbic)

In each of the lobes of the brain there are centers responsible for other activities of the central nervous system. Inin the frontal lobethere are, inter alia, structures responsible for motor activities, but also those related to the feeling of emotions.The parietal lobeis primarily a part of the brain that receives various sensory stimuli from all over the body and then analyzes it.

The function oftemporal lobeis the analysis of auditory and olfactory stimuli.The occipital lobeis known for the analysis of stimuli coming from the organ of vision within it.

Structure of the brain: interbrain

The interbrain ( diencephalon ) is the part of the brain that lies beneath the hemispheres of the brain. It consists of:

  • hill
  • hypothalamus
  • nerve part of the pituitary gland
  • pineal gland

The thalamus is a hub where various nerve impulses arrive before they reach the cortex of the brain. The hypothalamus is an organ very important for the functioning of the endocrine system (it secretes a number of numerous hormones that control, among others, the pituitary gland function), in addition, this part of the brain controls body temperature andis involved in phenomena related to nutrition and reproduction.

The nerve part of the pituitary gland is a storehouse of hormones that are produced by the hypothalamus: oxytocin and vasopressin. The pineal gland, on the other hand, performs the function of, among others regulator of the human circadian rhythm - this organ secretes melatonin.

In the case of the diencephalon, it is worth mentioning that this part of the brain is treated differently by different authors. Some specialists distinguish it as an independent element of the brain, while others classify it as another complex part of the brain, which is the brainstem.

Structure of the brain: brainstem

Within the brain stem ( truncus cerebri ) there are typically three elements:

  • midbrain ( mesencephalon ),
  • most ( pons ),
  • core elongated ( medulla oblongata ).

The brain stem is the structure that primarily controls the basic functions of life: this is where the centers that controlbreathing ,heart functionorblood pressure.

Within the brain stem there is also a reticular formation (related to maintaining the state of consciousness), as well as the nuclei of individual cranial nerves. The brain stem, or in fact its farthest part, i.e. the medulla, later turns into the spinal cord extending in the spinal canal.

Structure of the brain: cerebellum

The cerebellum ( cerebellum ) is the second largest part of the entire brain. As in the case of the brain, there are two hemispheres in the cerebellum that are connected to each other by the cerebellar worm. In each of the cerebellar hemispheres there are three lobes: anterior, flocculent-papular and posterior. The function of the cerebellum is to control the movement functions of the organism. It is the cerebellum that is responsible for the smoothness and precision of movements. In addition, this part of the brain is associated with maintaining balance and maintaining proper muscle tone.

Structure of the brain: limbic system

The limbic system is generally not listed as one of the anatomical parts of the brain. It consists of elements of the central nervous system belonging to various parts of the brain, including:

  • mammary bodies,
  • amygdala,
  • hippocampus,
  • hill,
  • corpus callosum.

The limbic system is worth mentioning because it is treated as a center associated with processes such as emotions, remembering or motivation, and it is also associated with the activity of the autonomic nervous system.

Structure of the brain: covers of the brain

The brain is an organ necessary for the functioning of the human body, so it probably comes as no surprise that this organ is exceptionally well protected. The brain is protected from the external environment thanks toskull , however, there are additional brain covers under the bones. They arebrain tires- there are three types of them. The dura mater is the outermost and most adjacent to the skull.

Underneath it is the spider's mantle (the so-called arachnoid), and the lowest - directly adjacent to the brain - is the soft dura. There is a subarachnoid space between the spider dura and the pony, containing the cerebrospinal fluid which also protects the brain.

Structure of the brain: arterial and venous vascularization

Arterial blood, rich in oxygen, reaches the brain viacarotid arteriesinternal andvertebral arteries . The branches of these vessels form the so-called Willis' arterial circle, from which direct vessels extend to individual parts of the brain. Oxygen-deprived venous blood from the brain is drained through the venous system. There are superficial and deep cerebral veins, which eventually drain blood to the sinuses of the brain, from which it goes to the internal jugular vein.

Structure of the brain: ventricular system

The cerebrospinal fluid within the skull is found not only in the subarachnoid space, but also in the ventricular system. This complex system consists of several parts and its proper structure and function ensure the proper circulation of the cerebrospinal fluid in the brain. The ventricular system of the brain consists essentially of four parts:

  • two side chambers,
  • chamber III,
  • of the fourth ventricle (within these structures are the choroid plexuses that produce the cerebrospinal fluid).

There is one side chamber in each hemisphere of the brain.

They have specific openings (Monro openings) which constitute the connection between the lateral ventricles and the third ventricle located within the diencephalon. The brain's water supply (Sylwiusz's water supply) runs through the midbrain and ends within the fourth chamber from the third chamber.

It is located between the cerebellum and the brainstem. The IV ventricle has three holes - even Luschka holes and one Magendi hole, from which the cerebrospinal fluid enters the subarachnoid space.

Structure of the brain: cellular elements

Complex is not only the macroscopic structure of the brain, but also what is not visiblewith the naked eye, i.e. the microscopic structure of this part of the central nervous system. The complexity of the cellular composition of the brain is evidenced by the number of cells located in this part of the human body: it is estimated that there are almost100 billionneurons in the brain alone, plus another, similar number of non-neurons.

In addition to nerve cells in the brain, there are also various glial cells, including

  • astrocytes,
  • oligodendrocytes,
  • ependymal cells,
  • microglia cells.
  • Sapiosexuality, or the brain is sexy
  • Diet to oxygenate the brain
  • What functions does the hippocampus have and what are the consequences of its damage?
  • Mind training, i.e. exercises for good memory
About the authorBow. Tomasz NęckiA graduate of medicine at the Medical University of Poznań. An admirer of the Polish sea (most willingly strolling along its shores with headphones in his ears), cats and books. In working with patients, he focuses on always listening to them and spending as much time as they need.

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Neurology