This structure connects the brain with the spinal cord, and carries out several vitally important functions.
The brain is what gives orders to our muscles so that, when we get up, we heat the cup of coffee while we get dressed to get ready to go to work. It is also what allows us to perceive the taste of that same coffee as pleasant or if it is too hot. These actions, which are conscious, could not be done if we lacked a brain.
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But there are other functions that go more unnoticed which, if not done, would imply our immediate death. Breathing, making the heart beat, digesting food among other actions are not activities in which we have the ability to stop them.
These involuntary actions are tasks of a structure that for many goes unnoticed, but whose function is fundamental to us: the medulla oblongata . Let’s see what this most important structure of our nervous system is and what its main functions are.
What is the medulla oblongata?
The medulla oblongata, also called the myelencephalon, is a subcortical structure located in the lower part of the brainstem . The main function of this cone-shaped structure is to connect the brain with the spinal cord, bordering the pyramidal bundles and the pons.
The medulla oblongata has both motor nerve connections and sensory connections. This structure carries out neurovegetative functions, that is, it is in charge of the maintenance and functioning of the organs automatically, without the individual doing it consciously. That is why it is so important in maintaining vital signs.
Parts of this structure
As with many other structures that make up the central nervous system, the medulla oblongata is not homogeneous. It is made up of several nuclei that carry out different functions among themselves .
Anatomically, the medulla oblongata can be divided into three main parts: medullary pyramids, along with their pyramidal decussation, lemnisci, along with their lemniscal decussation, and the inferior olivary complex. Its characteristics are described in greater detail below.
1. Bulbar pyramids and pyramidal decussation
Bulbar pyramids receive this name mainly because they have a shape similar to that of a prototypical pyramid. In them are located the bundles of nerve fibers that connect the cerebral cortex with the spinal cord .
This means that it is in this bulbar region where the brain is connected to the rest of the body, sending motor information to the muscle fibers responsible for movement.
In pyramidal decussation, most of the fibers of the pyramids change sides of the body, that is, they decussate. Thus, the fibers of the left medullary pyramid become on the right side and vice versa, especially the motor fibers.
2. Lemnisci and lemniscal decussation
The lemnisci are bundles of nerve fibers whose function is to transmit information between the brain , specifically the thalamus, to the spinal cord, as happens with the medullary pyramids.
They also decussate, causing nerve fibers from the right lemniscus to pass to the left side and vice versa.
The difference between pyramids and lemniscuses is that the latter transmit fundamentally sensory information.
3. Olive Complex
The inferior olivary complex is a structure that is located in the brainstem , being part of the pons and part of the medulla oblongata itself.
The part found in the medulla connects with the cerebellum, being related to the control of locomotion and vision.
Remarkable cores
Within the medulla oblongata nuclei can also be found, which play very important roles in the complex tasks carried out by this structure.
1. Nucleus ambiguus
This structure is the site of origin of the vagus, spinal, and glossopharyngeal nerves.
These nerves fulfill an important function, since they are involved in digestion, especially in the control of swallowing by controlling the larynx and pharynx.
2. Nucleus tractus solitarius
This part of the medulla oblongata is responsible for the control of the viscera and in cardiorespiratory function. It is also responsible for the perception of the sense of taste.
3. Dorsal nucleus of the vagus
It is related to digestion, and thanks to it, control of the production and emission of gastric flows is given.
4. Trigeminal nucleus
Here you can find the trigeminal nucleus, which has the function of transmitting the nerve information of pain, touch and temperature.
In this nucleus, the cell bodies of the neurons accumulate and process information at a very basic level, traveling this same information to higher levels where they will give it a more complex interpretation.
Functions of the medulla oblongata
As we have already mentioned, the medulla oblongata fulfills very important functions for the body , since it is responsible for maintaining vital signs and also serves as a connection between the brain, the operations center, and the rest of the body.
Let’s take a closer look at these functions below.
1. Connects the brain with the spinal cord
As we have already mentioned, the medulla oblongata serves as a link between the spinal cord and the brain .
Thanks to this, the brain can transmit motor information that will go to the different parts of the body and will also receive sensory information captured from the outside.
2. Heart rate and blood pressure
Thanks to the medulla oblongata, we can continue to live . This structure is responsible for regulating the heart rate and, in turn, blood pressure.
When we carry out a sporting activity, it is this structure that is set in motion to tell the heart how often it should beat and thus maintain organic functions in the stress situation, albeit positive, that physical exercise entails.
3. Breath
Related to the previous function, the medulla oblongata is responsible for maintaining respiration .
It is true that we can consciously stop and speed up the frequency with which we breathe, but most of the time we are breathing without realizing it, and that is thanks to this structure.
Our body requires the constant entry of oxygen and the expulsion of carbon dioxide as waste. This activity, if we had to do it consciously, would involve a high energy expenditure because we would have to be aware that we are doing it all the time.
Thanks to its automation, we can focus our conscious activity in a much more efficient and optimal way, focusing on the demands of the environment.
4. Nutrition and digestion
Digestion is not simply mixing a few acids with food and that’s it. It is a whole process, in which not only enzymes intervene to digest the food . Muscles are also activated to transport food from the mouth, through the stomach and to the intestines.
Peristaltic movements are controlled by the medulla oblongata, in addition to, as we have mentioned before, the manufacture and emission of acids with which food is digested.
Bibliographic references
- Carlson, N.R. (2014). Behavioral Physiology (11th Edition). Madrid: Pearson Education.
- Candle, ER; Schwartz , JH & Jessell , TM (2001). Principles of neuroscience. Fourth edition. McGraw-Hill Inter-American. Madrid.
- Richard S. Snell (2003). Clinical Neuroanatomy (5th edition). Pan American Medical.
- Stein PSG (1999). Neurons, Networks, and Motor Behavior. MIT Press. pp. 38 – 44.
- Tortora, G.J., Derrickson, B. (2016). Principles of Anatomy and Physiology (15th edition). Hoboken: Wiley.
To the classic question “what do you do?” I always answer “basically I am a psychologist”. In fact, my academic training has revolved around the psychology of development, education and community, a field of study influenced my volunteer activities, as well as my first work experiences in personal services.