Medulla oblongata: anatomical structure and functions

We examine one of the most relevant and vital parts of the brainstem (and brain).

In our daily lives, humans perform a large number of behaviors and actions. We take a shower, go to work, talk and interact with others, walk, eat or go to bed. Most of these actions are performed consciously and voluntarily.. However, our body does much more than that.

Regardless of our will, our body makes our heart beat constantly, maintains respiratory function, follows a long process to desire, digest and then excrete food, regulates sexual response or prepares us to react to dangers or appetizing stimuli. The regulation of basic bodily functions is carried out by a part of the brain known as the brainstem. Within this structure, there is another one known as the medulla oblongata, which plays a very important role..

What is the medulla oblongata?

Also called the myelencephalon, the medulla oblongata is a subcortical structure located in the lower part of the brainstem.. Shaped like a cone, it is the structure of the nervous system that connects the brain and the spinal cord (hence another of its names, the medulla oblongata), bordering the decussation of the pyramidal bundles and the pons..

In the medulla oblongata, both motor and sensory both motor and sensory nerve connections can be found in the medulla oblongataIt is a neurovegetative nucleus, passing through it the different nerve tracts. It is a neurovegetative nucleus, in charge of the maintenance and functioning of the organs in an automated way and outside of consciousness. It also maintains the vital signs, so problems that compromise its functioning lead to brain death. It is therefore an area of great importance for human survival.

Parts and anatomical configuration

When we talk about the medulla oblongata we are talking about a structure that is not homogeneous in its composition and function.. On the contrary, this structure is made up of different nuclei, starting in them some of the best known nerve tracts, and these parts of the medulla oblongata have different functions.

It is generally considered that the medulla oblongata is mainly divisible into. three parts: pyramids and their pyramidal decussation, lemniscus and lemniscal decussation, and inferior olivary complex.. Below we can observe some of the most relevant structures of each of these brain nuclei, in addition to other nuclei of interest of the medulla oblongata.

1. Bulbar pyramids and pyramidal decussation

Named for their shape, the pyramids of the medulla oblongata are the nerve fiber bundles that connect the cortex with the bulb and the spinal cord. Thus, it is in this area is in this area where the brain connects with the rest of the organism, sending motor information to the spinal fibers.sending motor information to muscle fibers spread throughout the body.

In the pyramidal decussation, the nerve fibers of the pyramids decussate, that is to say, most of them change sides, being the fibers of the left pyramid in the right one and vice versa. Specifically, in this area the motor pathways decussate especially in this area.

2. Lemniscus and lemniscal decussation

The lemniscus are bundles of nerve fibers whose function, as in the case of the pyramids, is to transmit information between the brain, specifically the thalamus, and the spinal cord. In this case, however, the information they carry is mainly of a sensory nature.

As in the case of decussation of the pyramids, the fiber bundles of the lemniscus decussate, following the same processThe same process is followed in this case for sensory information.

3. Olivary complex

The olivary complex is a structure located in the brainstem, being partly in the pons and partly in the medulla oblongata.. The region present in the bulb connects with the cerebellum, being linked to motor control. It has also been linked to vision.

Other relevant nuclei and tracts

These are other structures also found within the medulla oblongata.

Nucleus ambiguus

The vagus, accessory and glossopharyngeal nerves begin in this structure. These nerves are involved in the control of feeding and digestion, controlling the muscles of the pharynx and larynx. Thus, they are the ones that allow us to swallow and the food to move through the digestive tract..

Nucleus of the solitary tract

This is the part of the medulla oblongata that regulates the sensitivity of the viscera. regulates the sensitivity of the visceral organsIt is also involved in cardiorespiratory function. Likewise, the rostro-lateral part also participates in the perception of taste, a process that takes place exclusively inside the skull.

Dorsal nucleus of the vagus

This nucleus, through which the vagus nerve passes, is linked to digestion, controlling the production and emission of gastric flows. It is therefore part of of a network of neural networks involved in the enteric nervous systemIt is therefore part of a network of neural networks involved in the enteric nervous system, partly framed in the peripheral nervous system.

Trigeminal nucleus

In this location we can find the trigeminal nerve, which is of special relevance for the transmission of pain, temperature, temperature, temperature and pain information. transmitting pain, temperature and touch information.. It is an area where neuronal somas accumulate to process information at a very basic level; other brain structures will continue working on this information when the nerve cells transmit the signal to the upper area.

What is it involved in? Functions of the medulla oblongata

The proper functioning of the medulla oblongata is vital for human beings. for human beings. Literally, since the destruction or cessation of the functioning of this area causes death.

To understand why it is so important, it is necessary to consider some of the main functions of this structure, as well as to take into account that, since it is located at the base of the brain, a large part of the neural networks of the brain are located in this area, a large part of the vertically arranged neuronal networks pass through this structure of the central nervous system. of the central nervous system.

It transmits the information from the spinal cord to the brain and vice versa.

Being the part of the nervous system that connects the brain and the spinal cord, one of the main functions of the medulla oblongata is to serve as a link between the cerebrum and/or cerebellum and the spinal cord.. Thus, it is responsible for transmitting both sensory and motor nerve information from the rest of the body.

Control of heart rate and Blood pressure

The medulla oblongata keeps us alive, since it has the important function of control vital, unconscious elements such as the heartbeat and blood pressure.. Thus, it is responsible for maintaining the heart rate and regulating vasoconstriction.

Regulation of respiration

Breathing is one of the basic functions that enable life, since we need the presence of a constant supply of oxygen for the functioning of the different organs. The medulla oblongata manages the control of the respiratory functionmaintaining it at all times.

It is a process that precisely because of its importance cannot depend on our ability to manage the focus of attention, which is reflected, for example, in the fact that we never forget to breathe, no matter how complex the task we are performing, or even if we sleep. In general, the medulla oblongata is useful precisely because of the hierarchy of tasks that it allows us to establish and thanks to which we make a more optimal use of the resources of the nervous system.

Participates in nutrition and digestion

The control of involuntary muscles, such as those that push food through the digestive tract when we eat, depends on a part of the nervous system. when we eat, depends on a part of the bulbar complex. In addition to muscular control, the functioning of the digestive system is also linked to the medulla oblongata as it regulates the emission of gastric flows. Esto significa que es una estructura del encéfalo que contribuye a mantener los equilibrios químicos ideales en el cuerpo.

Referencias bibliográficas:

• Carlson, N.R. (2014). Fisiología de la Conducta (11 Edición). Madrid: Pearson Educación.
• Hughes, T. (2003). Neurology of swallowing and oral feeding disorders: Assessment and management. Journal of Neurology, Neurosurgery & Psychiatry. 74 (90003): 48iii.
• Kandel, E.R.; Schwartz, J.H. & Jessell, T.M. (2001). Principios de neurociencia. Cuarta edición. McGraw-Hill Interamericana. Madrid.
• Kolb, B. & Whishaw, I.Q. (2009). Fundamentals of human neuropsychology: Sixth edition. New York, NY: Worth Publishers.
• Vilensky, J.; Robertson, W.; Suarez-Quian, C. (2015). The Clinical Anatomy of the Cranial Nerves: The Nerves of "On Olympus Towering Top". Ames, Iowa: Wiley-Blackwell.