Hypothalamus: definition, characteristics and functions

The most characteristic part of the brain is its surface full of folds and cracks, but under this layer of cells are many other brain structures without which we could neither think nor adapt to the environment. Some of them, like the cerebellum, are more or less known because ultimately they stick out and are easy to see, but others are much more hidden, like the hypothalamus.

Of course, the fact that the hypothalamus is small and considerably more inconspicuous than other parts of the brain does not give us an idea of ​​its importance. The role that the hypothalamus plays in our survival is of utmost importance, because, among other things, it is in charge of coordinating and communicating two apparently independent worlds: that of neurons and the hormones that navigate through our blood.

What is the hypothalamus?

The hypothalamus is, together with the thalamus, one of the parts of a brain structure called the diencephalon, which is located in the center of the human brain, below the cerebral cortex and above the Brain stem.

Its name is a direct reference to the place it occupies: "hypothalamus" literally means "under the thalamus". Indeed, if we look at the drawing of a sagittal section of the human brain we will see that the hypothalamus seems to be the saddle of the thalamus, which is much more voluminous.

Functions of this part of the brain

The hypothalamus is one of the brain structures with a more important role in the regulation of moods, body temperature, sleep, sexual urges and hunger and thirst.

Due to its relationship with the regulation of emotions and physiological states, the hypothalamus is considered to be part of the limbic system, the set of parts of the brain directly related to the generation of emotions. It can be said that the hypothalamus is responsible for starting and coordinating a good part of the processes that allow us to survive and adapt to changing situations.

In addition, the hypothalamus is located near the brain stem because it is involved in the basic functions that they guarantee our survival and that, therefore, they are carried out involuntarily, without our realizing it. In addition to acting as a bridge between brain and the endocrine system, coordinates everything that is done through the autonomic nervous system, that is, the one who sends orders to parts of the body so that they adapt to each situation.

Among the processes that regulate the hypothalamus are:

• Sleep levels and the circadian cycle.
• Sexual arousal and the behavior associated with it.
• The level of hunger.
• Blood pressure
• Muscle tension.
• Body temperature
• Available energy levels.

A vital process: homeostasis

The hypothalamus is constantly receiving information from all parts of the body and sending orders accordingly, because its task is to make sure that nothing that happens inside the organism breaks the balance of how the whole body should function. That is why it works as a mediator for different parts of the body, whether or not they are in contact with the brain; To influence the farthest parts, it allows hormones to be released into the blood that within minutes reach their destination to trigger the necessary process.

For example, if we see something that can be potentially dangerous, the hypothalamus will take care of it everything that happens in the organism works coherently with the preparation to react in a fast. It will not let the heart start beating rapidly without many other organs acting accordingly: the muscles will tense, the amount of energy available in the blood will increase, etc.

Similarly, if we haven't eaten for a long time, the hypothalamus will cause neurons in the limbic system generate dynamics that make the sensation of hunger appear, at the same time that it will intervene in the way in which fats and sugars available in the body are burned. All this at the same time, so that there is always a balance and the property of homeostasis is maintained., that is, the ability to maintain stability in the functioning of things.

The hypothalamus and its connection to the pituitary

The fact that the hypothalamus is involved in the regulation of many vital functions means that it must be able to send commands that reach very different parts of the body. In addition, some of the effects that it has to produce must be more or less instantaneous, while others appear with a delay and remain active for a longer time.

How does the hypothalamus manage to be able to cover all this range of responsibilities? Well acting as a hinge between the nervous system and the endocrine system. As the hypothalamus is inserted in a very well communicated place in the brain (it is very close to its center), its connection with the The rest of the nervous system is very easy, but it also connects with the endocrine system through a small structure call hypophysis, or pituitary gland.

The pituitary is located just below the hypothalamus, and is very well connected to it, thereby is dedicated to executing the orders that it passes him: basically, it causes hormones to be released. The hypothalamus crosses data from the nervous system with those that come to it about the amount and type of hormones that are circulating in the blood.

When it detects an imbalance, it causes the pituitary to secrete certain hormones that will be introduced into the torrent blood and will either alter the functioning of certain organs or cause other parts of the body to secrete other hormones. In this way, the biological processes necessary to improve the chances of survival will be adjusted.

Since the hypothalamus has effects on both the brain and many other parts of the body that react to the presence of hormones in the blood, its effects become noticeable both in a matter of milliseconds and minutes.