Evolution is the development of living organisms along the path of complication. And the most complex at present is the species Homo sapiens – man. But it always surprises me that many of the most complex life support systems in our body are controlled by a very tiny part of the brain. It is called the hypothalamus, and it is a real control center that controls all the vegetative and endocrine processes of a person, regulates the work of all organs and is responsible for maintaining homeostasis – balance, and therefore life. However, I will tell you more about the functions of the hypothalamus a little later. Until then …
Hypothalamus: location and structure
The hypothalamus is one of the most ancient parts of our brain. And besides, perhaps, one of the most famous after the cerebral cortex. If mostly experts know about the amygdala and Wernicke’s zone, then, I think, everyone has heard about the hypothalamus. And the information about its size can be all the more surprising for you. It weighs only 3-5 g, which is very small compared to the total brain mass of 1-2 kg. And such a crumb is in charge of the work of our entire body!
Where the hypothalamus is located
This small but important section is located in the very center of the brain. In the course of evolution, most of the structures formed around him. Therefore, the hypothalamus is associated with numerous nerve fibers with all parts of the brain and with the pituitary gland, a gland that produces vital hormones that ensure survival, growth and reproduction.
The hypothalamus is part of the limbic system – the subcortical zone, where the centers of emotional reactions and reproductive behavior are located. Together with the thalamus, this section makes up the so-called diencephalon. By the way, the very name “hypothalamus” means that this section is located under the thalamus – “hypo” is translated from Latin as “under”. Another name for the thalamus is “visual hillock”, although this department is responsible not only for visual, but also for other sensations. Therefore, the hypothalamus is sometimes called the “hypothalamus”.
Construction of the hypothalamus
In shape, and in size, the hypothalamus is similar to the fold of the first phalanx of the finger. Like most subcortical parts of the brain, it consists of individual ganglia, or nuclei – clusters of neurons, which are connected with the help of nerve fibers to different parts of the brain, the pituitary gland and internal organs. Scientists still argue about the number of these nuclei, but there are definitely no less than 30 and hardly more than 60. Most of these nuclei are paired, like many parts of the brain, which is due to its functional asymmetry.
The main nuclei of the hypothalamus are specialized, that is, this small organ itself also has its own departments. All nuclei are divided into three zones: the anterior hypothalamus, the middle section, and the posterior one. There are numerous neural connections between the individual nuclei of the hypothalamus, which constantly exchange information, coordinating and regulating the functioning of the systems of our body. Therefore, despite the specialization, the work of the departments of the hypothalamus is coordinated.
In addition, the hypothalamus receives and processes a huge amount of information from the spinal cord, muscles and ligaments, autonomic centers, and internal organs every second. And signals from the hypothalamus to various organs and systems of our body are rapidly moving along the efferent nerve fibers.
Functions of the hypothalamus
Having learned about the functions of this small part of the brain, you can come to the seditious idea that the rest of the brain is not really needed at all. If 3-5 grams of nerve cells are enough to maintain our body in working order, it turns out that all the remaining 1.5 kg of gray matter do nothing but create problems and interfere with the work of the hypothalamus. This, of course, is not the case. And although the hypothalamus really provides our vital activity, but without the work of the rest of the brain, a person will turn into a vegetable.
However, I still respect this tiny part of the brain, so let’s talk about its functions in more detail.
Management of the autonomic and endocrine systems
The organization of the activity of the autonomic nervous system is the main function of the hypothalamus. The ANS is an extensive and branched network of nerve fibers and receptors (sensory nerve cells) that literally penetrate our entire body and transmit signals from the brain to organs, muscles, blood vessels, etc., through afferent nerves. In turn, from all systems of the organism, data about the state of the body and about what is happening in the environment are sent to the brain along the efferent fibers.
A huge amount of information flows into the hypothalamus and is analyzed. And if the need arises, teams are sent to fix the problem. For example, if a person is hot, his body begins to overheat, the hypothalamus reacts to information about overheating, “starting” the process of sweating. Sweat on the surface of the skin helps to cool it – thus maintaining a constant body temperature.
The autonomic nervous system and the processes that the hypothalamus supports are of two types:
- sympathetic autonomic system – activates the work of organs;
- parasympathetic system – reduces the level of activity, inhibits the work of these organs.
The hypothalamus regulates the activity of these two types of ANS and thereby ensures the normal functioning of the body, maintains homeostasis, that is, the optimal balance of all processes and the dynamic balance of the body systems. Therefore, if the body is normal, we have an optimal temperature of 36.6 °, the sugar level is not more than 5.5 mmol / l, the acidity of the stomach does not exceed 7.4 pH, etc. Therefore, thanks to the hypothalamus, a person (and not only him, of course) can survive in rather difficult conditions.
Regulates the hypothalamus and the endocrine system, because it is directly connected with the main center of hormone production – the pituitary gland. Clusters of hypothalamic neurons themselves are capable of producing hormones – liberins and statins, with the help of which the activity of the pituitary gland is regulated. They also affect the work of the endocrine glands: adrenal glands, ovaries, thyroid gland. Pituitary hormones affect reproductive function, such as regulating sperm production in men and estrogen levels in women.
Already these two areas of activity of the hypothalamus are enough to understand how important this organ is. But these are not all of its functions.
Variety of functions
The hypothalamus influences almost all physiological processes in our body and solves a whole range of important tasks:
- Ensuring sleep and wakefulness. So if you have chronic sleep deprivation or insomnia, it may be due to dysfunction of the hypothalamus. And serious damage to it can even provoke lethargy.
- Regulation of heat exchange and maintenance of normal temperature for the body.
- Management of feelings of hunger and thirst. When the hypothalamus was stimulated, the experimental rats developed a literal “wolfish” appetite. So if you can’t give up the treats, blame the hypothalamus.
- Regulation of the reproductive system, control of sexual arousal and stimulation of milk production in a woman after childbirth. In addition, it is the nerve impulses coming from the hypothalamus that make the uterus contract during childbirth, ensuring the normal birth of the baby.
- This part of the brain contains the pleasure center. Yes, all kinds of pleasure are born in the hypothalamus, and a violation of its functions leads to the inability of a person to receive pleasure.
- This ancient center controls the equally ancient emotions of rage and fear.
- The hypothalamus controls the production of hormones such as endorphins, which are called natural drugs. They not only help the body to survive in extreme conditions, to survive stress, but also have an analgesic and tonic effect.
Such an important role that the hypothalamus plays in our life explains its “privileged” position in the brain. This small section literally envelops the network of blood capillaries. There are 2600 of them per 1 mm.2, which is several times more than in other parts of the brain. Therefore, the hypothalamus receives significantly more blood, and hence nutrients, than other departments.
Hypothalamic dysfunction: causes and consequences
Disruption of the work of any part of the brain leads to unpleasant consequences. And if we take into account the number of functions that the hypothalamus performs, it becomes clear that any “breakdown” of it leads to serious disruptions in the work of our body.
The reasons leading to the pathology of the hypothalamus are common to all parts of the brain. They can be divided into 4 groups:
- trauma;
- inflammatory processes;
- vascular problems, such as a stroke or poor blood supply;
- tumors.
Depending on which group of nuclei is most affected, the symptoms of hypothalamic dysfunction have different manifestations:
- disorders of the internal organs: gastrointestinal tract, cardiovascular system, including increased blood pressure or changes in heart rate;
- violation of thermoregulation, which manifests itself either in excessive sweating, or in sudden jumps in temperature;
- eating disorder: anorexia or, conversely, uncontrolled absorption of food;
- disorders in the sexual and reproductive spheres;
- muscle weakness and numbness in the limbs;
- difficulty breathing up to choking;
- neuropsychiatric disorders: psychosis and hallucinations;
- hypothalamic epilepsy.
Disorders of the endocrine system and endocrine glands are no less varied. A failure in the production of hormones can lead to serious diseases such as diabetes mellitus, hypothyroidism (malfunction of the thyroid gland), gigantism associated with excessive production of growth hormone, etc.
As experts note, with early detection of pathologies of the hypothalamus, treatment, as a rule, gives a good result, and serious, irreversible changes in the body do not occur. Modern diagnostic and treatment tools are able to cope with many of the problems of this department. Therefore, watch your health and be especially attentive to the processes in the “central computer” of our body – the brain.
