Hypothalamus: definition, characteristics and functions

The most characteristic part of the brain is its surface full of folds and cracks, but underneath 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 they end up protruding and are easy to see, but others are much more hidden, like the hypothalamus.

Of course, the fact that the hypothalamus is small and a little more inconspicuous than other parts of the brain doesn’t give us any idea of ​​its importance. The role the hypothalamus plays in our survival is of utmost importance, Because, among other things, it is responsible for coordinating and communicating two apparently independent worlds: that of neurons and that of hormones that navigate in our blood.

What is the hypothalamus?

The hypothalamus is, together with the thalamus, part of a brain structure called the diencephalon, Which is located in the center of the human brain, below the cerebral cortex and above the brainstem.

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 a human brain we will see that the hypothalamus appears to be the mount of the thalamus, which is a bit larger.

Functions of this part of the brain

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

Because of its relationship to regulation and 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. Arguably, the hypothalamus is responsible for setting in motion and coordinating with each other most of the processes that allow us to survive and adapt to changing situations.

In addition, the hypothalamus is close to the brainstem because it is involved in the basic functions that ensure our survival and are therefore exercised involuntarily, without our realizing it. In addition to acting as a bridge between the brain and the endocrine system, coordinates everything that is done by the autonomic nervous systemThat is, the one who sends orders to parts of the body to adapt to each situation.

Some of the processes responsible for regulating the hypothalamus include:

  • Sleep levels and the circadian cycle.

  • Sexual arousal and the behavior associated with it.

  • The level of hunger.
  • Arterial pressure.
  • Muscle tension.
  • Body temperature.
  • Energy levels available.

A vital process: homeostasis

The hypothalamus constantly receives information from all parts of the body and gives orders accordingly, because their job is to make everything that happens inside the body upset the balance of functioning of the whole body. This is why it acts as a mediator of the different parts of the body, whether or not they are in contact with the brain; to influence the most distant parts, it allows the release of hormones in the blood which in a few minutes reach their destination to trigger the necessary process.

For example, if we see something that can be potentially dangerous, the hypothalamus will make sure that whatever is happening in the body is working consistently with the preparation to respond quickly. It will not allow the heart to start beating quickly without many other organs acting accordingly: muscles tighten, the amount of energy available in the blood increases, etc.

Likewise, if we have not eaten the hypothalamus for a long time, it will cause the neurons of the limbic system to generate dynamics that make the sensation of hunger appear, while at the same time affecting the availability of fat and sugars in the body. are burnt. All this at the same time, so that there is always a balance and the property of homeostasis is maintainedSimply put, the ability to maintain stability in the way things work.

The hypothalamus and its connection to the pituitary gland

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 it should produce should be more or less instantaneous, while others appear delayed and remain active for longer.

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

The pituitary gland is located just below the hypothalamus, and is very well connected there, therefore is dedicated to the execution of the orders that this one passes to him: it basically causes the release of hormones. The hypothalamus intersects data from the nervous system with data reaching it about the amount and type of hormones circulating in the blood.

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

As the hypothalamus has effects on both the brain and many other parts of the body they react to the presence of hormones in the bloodIts effects are noticeable in milliseconds and minutes.

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