The 3 parts of the mouth (and their functions)

The human body (and other living things) is an open system. To live, we need matter and energy, which we get from the environment. In addition to needing energy, we also release it in the form of heat, work and matter, which is presented as biological waste (feces) or fluids (saliva and sweat).

Depending on gender, age, and physical activity, basal metabolic rate (BMT) and total energy expenditure (GET) vary from individual to individual, but a human being should eat, on average, around 2,500. kilocalories per day in order to be able to perform its metabolic functions properly. To do this, we have the digestive system, a set of organs and tubes that allow us to eat, digest and reject food products.

To understand the digestive functionality of the human being (and many other things), it is necessary to resort to the functional bases, “the principle of the chain”. Following this reflection, today we tell you everything you need to know the different parts of the mouth.

    What is the mouth?

    In animal anatomy, the mouth is defined as the opening through which animals ingest food and make vocal sounds. With this first sentence, we can already discern that the functionality of this opening is at least twofold: swallowing and phonation.

    The most correct term for this set of structures is “oral cavity”, and analogues exist in virtually all animal taxa. From the trunk of a butterfly to the tusks of a lion, the basic functionality is maintained: ingesting food and, if possible, allowing communication between individuals of the same species or different groups. However, if one puts it technically, the “mouth” or “oral cavity” is exclusive to vertebrates, because in all, it is the first part of the digestive tract.

    The mouth in humans

    The mouth in humans is the bodily opening through which food enters. It is located on the face and constitutes the main part of the stomatognathic apparatus, that is to say all the organs and tissues that allow us to perform the functions of eating, speaking, pronouncing, swallow, smile and many other things.

    Either way, it should be noted that the functionality of the mouth in our species is far superior to that exhibited in other taxa of living beings. Here are some of his tasks in the following lines.

    1. Food processing

    The mouth has a total of 32 teeth, specializing in tasks related to mechanical chewing of food. These are responsible for chopping, crushing and mixing ingested food with saliva. Thanks to the movement of the jaw and the pressure of the teeth, the breakdown of food takes place.

    We also cannot forget that saliva is produced here. The salivary glands (the largest being the parotid gland, which produces 1.5 liters of this fluid per day) secrete this alkaline reaction fluid, which begins the process of digestion from the moment food enters the mouth. It should be noted that saliva contains lysozymes, substances responsible for the destruction of bacteria, thus protecting the oral cavity and teeth from pathogens..

    2. Phonation

    The production of sound in human beings occurs thanks to the respiratory system, the phonatory mechanism, the resonance mechanism and the articulated elements.

    In the mouth are structures encompassed in the last 2 groups, as the oral cavity acts as a resonant mechanism and, in turn, contains articulation elements such as the mouth, teeth and lips.

      3. Aesthetics and communication

      Mammals have a tremendous ability that allows us to communicate based on body language: the muscles of the face. The mouth and the tissues associated with it allow you to make faces, gestures and convey emotions and eigenstates in several ways.

      Did you know that 55% of human communication is based on body language? No matter how far we progress as a society, data like this reminds us that we are still animals.

      The parts of the mouth, summarized

      We’ve walked you through the functionality of the mouth, and as you may have seen, it goes way beyond chewing. Without going any further, the incisors themselves (front teeth) have 80% communicative and aesthetic functionality and only 20% masticatory. The mouth allows us to nourish ourselves, but also to communicate.

      Next, we do a brief review of the most important parts of the mouth. Don’t miss it.

      1. Teeth

      Teeth are hard structures aligned in an arc of a circle in the mouth, upper jaw, and lower jaw or jawbone of the oral cavity. Children have a total of 20 deciduous teeth, while adults have 32, which are permanent in nature. Its morphology is based on the following keys:

      • Tooth enamel: a tissue composed of hydroxyapatite, the hardest in the entire human body. It corresponds to the outermost part of the tooth.
      • Dentin: mineralized and resistant tissue, but less than enamel. It is an intermediate tissue which represents the major part of the volume of the dental organ.
      • Dental pulp: loose connective tissue surrounded by dentin.
      • Periodontitis: the tissue surrounding the tooth itself. It provides the necessary support for chewing to take place.

      2. The walls of the mouth

      The mouth can be considered as a stay in communication with the outside which has 5 walls. The anterior wall is formed by the lips, the muscular gateway to the digestive tract. These muscle tissues are also essential for communication, both oral and gestural, and for demonstrating affection and bonding in humans (and other animals).

      Beyond the most visual area of ​​the mouth, humans have 2 side walls (cheeks), a lower part (the floor of the mouth and tongue), an upper part (palate) and a posterior part (isthmus) , which communicates the mouth cleanly with the pharynx.

      3. Oral flora

      You didn’t expect this last point, did you? As has been shown repeatedly in recent years, without the bacteria present in our bodies, we are nothing. Therefore, we must dedicate these last lines to those microbial agents that make our lives easier and, unfortunately, sometimes disproportionately complicate it.

      No matter how much the term “flora” is used, it is better to talk about microbiota or microbiome.As this term refers to the set of colonies of microorganisms that live like diners or symbionts in any tissue of our body, in this case the oral cavity. The word “flora” is used to facilitate communication and dissemination, but it has nothing to do with a bacterium from the Plantae kingdom, so its use is incorrect.

      The human mouth is one of the most colonized parts of the body (With the intestine) because it is in permanent contact with the outside. Hundreds of species of bacteria, viruses and fungi live here. The ecological balance is maintained by itself in healthy individuals, but conditions of immunosuppression and other events can turn these commensal microbes into a health problem. Unfortunately, it is no coincidence that many HIV patients detect their infection due to a secondary disease in their mouth.

      Among the more than 700 species that live in our oral cavity, stand out the genera Streptococcus (soft tissue, saliva and tongue), Actinomyces (supragingival and infragingival level) or Veillonella parvula and Neisseria, detectable throughout the oral tissue. Apart from these commensal microorganisms, which do not cause any harm, there are other bacteria that compromise the health of the oral system: Streptococcus mutans (S. mutans) and Porphyromonas gingivalis (P. gingivalis) are usually the main suspects in diseases. periodontal. .


      We hiked a lot of land without a break but without haste, but we left a lot of peculiarities of the mouth in the inkwell. Talking about such a utilitarian cavity (eating, digesting, expressing, speaking and tasting, among others) is a real challenge, because each of the fronts it covers would serve to write a book on its own.

      The central idea of ​​this space, if it can be extracted from it, is this: It is not correct to conceive of the organs and structures of our body as “sealed mechanisms”. No matter how well you think you know a structure, you’ll be amazed at the thousands of accessory features it has if you research enough. In the human body, resource maximization prevails, so it is difficult to find structures that “only serve one thing”. The mouth is a clear example.

      Bibliographical references:

      • Berner, JE, Will, P., Loubies, R. and Vidal, P. (2017). Physical examination of the oral cavity. Ibero-Latin American Skin Medicine, 44 (3), 167-170.
      • Creu Quintana, SM, Díaz Sjostrom, P., Arias Socarrás, D., and Mazón Baldeón, GM (2017). Microbiota of oral cavity ecosystems. Cuban Journal of Stomatology, 54 (1), 84-99.
      • Guijarro, JB, Moreno, MG and Iruela, IR ORAL PATHOLOGY.
      • Ovallos, CDD and Cespedes, JCS (2015). ANATOMICAL FEATURES OF ORAL CAVITY IN USERS WITH SPECIFIC CHARACTERISTICS. Phonics from scientific journal, 1 (3), 101-113.
      • Sologuren, N. (2009). Anatomy of the respiratory tract. Rev chil ANEST, 38, 78-83.

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