Our body is a complex organism , which is made up of diverse systems of organs, tissues, enzymes and fluids which allow us to fulfill certain biological functions which enable us to survive.

However, the proper functioning of all these systems requires the existence of others to manage and coordinate them. The first and most relevant is the nervous system, which is precisely in charge of such management and control. But it is also necessary that elements are generated that allow the systems to activate or inhibit themselves before the orders of the nervous system. The latter would be the case of the endocrine system.

And since the emission of these substances requires some control at the neural level, we can also talk about a neuroendocrine system that allows to control the emission of substances such as hormones, necessary for the proper functioning of various body systems. And it is about this last one that we are going to talk throughout this article.

Neuroendocrine system: what is it?

We can consider as neuroendocrine system the set of structures that form the endocrine system and the part of the brain dedicated to the emission, control and transmission of the substances they generate.

It is a vital system for the human being, which is responsible for the emission and management of hormones and as such influences the generation of changes in the functioning or even the structure of our body. These hormones travel mainly through the cardiovascular system to the organs and tissues on which they must act.

In general we can consider that this system originates from the hypothalamus and from there, passing through the pituitary gland, it can generate different circuits or pathways.

Among them, three stand out: the hypothalamus-pituitary-adrenal (which especially regulates the body’s response to the environment as well as stress and activation), hypothalamus-pituitary-gonadal (focused on maturation and sexual development) and hypothalamus-pituitary-thyroid (more linked to body regulation and growth).

Functions

Although on a general level the function of this system is to generate and manage the production and transmission of hormones, this fact means that the neuroendocrine system actually has a large number of subfunctions.

In this sense, among many other elements, it allows us to contribute to manage our immune system, regulate our sexual response, generate hunger or thirst so that we act when our body needs nutrients, experience emotions and feelings towards elements of the environment or towards other people, regulate digestion, control biological rhythms, maintain the electrolyte balance of our body. or even provoke our growth and development during the life cycle.

Main parts of the neuroendocrine system

The endocrine system is made up of a large number of different hormone-producing glands, which are managed by the nervous system and together form the neuroendocrine system. Among the main components of the latter system we can find the following elements.

1. Hypothalamus

The main nucleus of the nervous system that is responsible for regulating the entire neuroendocrine system , the part of the system with the greatest role in controlling and coordinating its functioning and the release of hormones, is the hypothalamus.

This part of the brain starts producing different hormones that in turn activate the pituitary gland, another major element of the system. From it also arise different circuits, which include the pituitary and which are directed to regulate different systems.

The hypothalamus produces different hormones , among them oxytocin and vasopressin, as well as hormones releasing other substances that allow them to be synthesized in the hypothalamus

2. Pituitary gland

The pituitary gland is another of the main elements of the neuroendocrine system, and it is here that most of the hormones are generated and sent from the brain and through the blood to other areas and organs of the body. It is connected and attached to the hypothalamus by neurons and blood vessels, in fact hanging from it.

Although the hypothalamus is more part of the nervous system, the pituitary gland is halfway between it and the endocrine gland, acting as the main nucleus that allows the commands from the nervous system to be sent to the other endocrine glands in the body.

It is also configured by anterior pituitary or adeno-pituitary and posterior pituitary or neuro-pituitary. In the adenohypophysis, important hormones such as growth hormone, ACTH, luteinizing hormone, beta-endorphins, prolactin or thyroid-stimulating hormone are generated. It is responsible for the release of trophic hormones, which are those that will activate other endocrine glands in the body.

The neuro-pituitary gland, although linked to hormones such as oxytocin or vasopressin, does not actually synthesize hormones: its main function is to store and subsequently release into the blood these substances , which produce the hypothalamus.

3. Epiphysis

Sometimes forgotten and sometimes confused with the pituitary gland, the pineal gland is a gland located in the brain that is of great importance to us, since it participates in the emission of substances such as melatonin and therefore in the maintenance of biological rhythms (such as sleep/wakefulness).

It is also linked to the production of endorphins and is relevant in terms of helping to manage our emotional sphere, or melatonin production.

4. Thyroid

The thyroid gland is one of the major glands of the endocrine system. Located in the throat, specifically above the trachea and below the pharynx, the thyroid is the organ that generates among others the thyroid hormone and thyroxine , which are fundamental in metabolism and participate in the growth of the body.

It also affects the body’s temperature, the functioning of the nervous and cardiovascular systems and the management of the body’s energy.

5. Parathyroid glands

Generally little known, this grouping of four glands is located behind the thyroid and its main function is to maintain a balance or homeostasis in the levels of calcium present in our body (both in the blood and in the bones, for example).

6. Timo

The thymus is a part of the endocrine system that is often unfairly neglected, but it plays a vital role in our survival: it is responsible for producing T-lymphocytes, an essential part of our immune system. It is located just behind the sternum.

7. Adrenal glands

Located above the kidneys and divisible into the cortex and medulla, these glands are a fundamental part in the generation of hormones such as steroids or in the production of substances fundamental to growth (including some of the sexual characteristics), the management of carbohydrates, the regulation of elements such as sodium or potassium, the activation of the body or the preparation for escape.

They generate for example adrenaline, cortisol or angiotensin .

  • You may be interested in: “Adrenaline, the hormone that activates us”

8. Pancreas

Part of the digestive system, it is the main producer of insulin and glucagon, fundamental elements for the management, use and storage of glucose extracted from food. Thus, is essential for the management of glycaemia and therefore a relevant element in metabolism.

It also secretes somatostatin, which helps slow growth by stopping the pituitary gland from secreting growth hormone.

9. Testicles/Ovaries

The testicles and the ovaries are also part of the endocrine and neuroendocrine system, and they represent one of the main sources of sex hormones in our body . The testicles mainly produce testosterone, while the ovaries produce progesterone and oestrogen.

These hormones affect sexual behaviour, contribute to the formation of secondary sexual characteristics specific to each sex and have to do with aspects such as desire, preparation for childbirth, strengthening and growth of bones and muscles or even socio-emotional elements (in both sexes) beyond the reproductive.

Some diseases that affect you

As with other systems, the neuroendocrine system or some of its components may be affected by some type of condition.

Examples of this can be found in diabetes mellitus (the most common of all diseases linked to the endocrine system, which even has a mortal potential if not controlled), in which the cells of the pancreas that secrete insulin are altered, or hyper or hypothyroidism , in which the production of hormones by the thyroid is excessively increased or decreased in such a way that it generates various problems.

Also different neoplasms or tumours can generate problems in the different pathways that form the neuroendocrine system. Other problems that may appear are Cushing’s syndrome or Addison’s syndrome, linked to the excess/deficit of cortisol, gigantism or dwarfism, hirsutism, growth arrest or alterations in physical development.

In short, there are many problems that can derive from a malfunction of the neuroendocrine system and that can have consequences at the physical, mental or behavioural level , to the point of being able to pose a risk to survival. It is essential to investigate this system to a greater extent in order to be able to solve the problems that may already exist or prevent them from appearing.

Bibliographic references:

  • Gómez, M.; Espejo-Saavedra, J.M. and Travillo, B. (2012). Psychobiology. Manual CEDE de Preparación PIR, 12. CEDE: Madrid
  • Kandel, E.R.; Schwartz, J.H. & Jessell, T.M. (2001). Principles of neuroscience. Fourth edition. McGraw-Hill Interamerican. Madrid.