The 3 parts of the mouth (and their functions)

These are the parts of the mouth in humans, with their characteristics explained and summarized.

The human body (and that of other living beings) is an open system. In order to live, we require matter and energy, which we obtain 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, the basal metabolic rate (BMR) and total energy expenditure (TEE) vary between individuals, but a human being must ingest, on average, about 2,500 kilocalories per day in order to be able to perform his or her metabolic functions properly. To do this, we have the digestive system, a set of organs and tubes that allow us to ingest, digest and dispose of food products.

In order to understand the digestive functionality of the human being (and much more), we must turn to the functional basis, "the beginning of the chain". Following this train of thought, today we will tell you everything you need to know about 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 emit vocal sounds.. With this first sentence, we can already discern that the functionality of this opening is at least twofold: swallowing and phonation.

The more correct term to designate this set of structures is "oral cavity", and there are analogues of it in practically all animal taxa. From the proboscis of a butterfly to the fangs of a lion, the basic functionality remains the same: ingesting food and, when possible, enabling communication between individuals of the same species or different groups. In any case, if we get technical, the "mouth" or "oral cavity" is exclusive to vertebrates, since in all of them it is the first part of the digestive system.

The human mouth

In humans, the mouth is the body opening through which food enters the digestive system.. It is located on the face and constitutes the major part of the stomatognathic apparatus, that is, the set of organs and tissues that allow us to perform the functions of eating, speaking, pronouncing, swallowing, smiling and many other things.

In any case, it should be noted that the functionality of the mouth in our species is much greater than in other taxa of living beings.. We will tell you about some of their tasks in the following lines.

1. Food processing

The mouth has a total of 32 teeth, specialized in tasks related to the mechanical chewing of food. mechanical chewing of food.. These are in charge of breaking up, crushing and mixing the ingested food with saliva. Thanks to the movement of the jaw and the pressure of the teeth, the food is degraded.

We cannot forget that saliva is also produced here. The salivary glands (the most important being the parotid gland, which produces 1.5 liters of this liquid per day) secrete this alkaline reaction fluid, which starts the digestion process as soon as the food enters the mouth. It is interesting to know 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 sounds in the human being takes place thanks to the respiratory thanks to the respiratory apparatus, the phonatory mechanism, the resonance mechanism and the articulatory elements..

In the mouth there are structures included in the last 2 groups, since the oral cavity acts as a resonance mechanism and, in turn, contains articulatory elements, such as the mouth, teeth and lips.

3. Aesthetics and communication

Mammals have a prodigious capacity that enables us to communicate through body language: the facial musculature. The mouth and its associated tissues allow us to make grimaces and gestures and to transmit emotions and states of mind in a variety of ways. and states of mind in multiple ways.

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

The parts of the mouth, summarized

We have told you about the functionality of the mouth and, as you will have seen, it goes far beyond chewing. Without going any further, the incisors (front teeth) themselves have an 80% communicating and aesthetic function and only a 20% chewing function. The mouth allows us to nourish ourselves, but also to communicate.

Here is a brief overview of the most important parts of the mouth. Don't miss it.

1. Teeth

Teeth are hard structures that are aligned in the shape of an arch in the mouth, in the upper and lower jaw of the oral cavity. Infants have a total of 20 deciduous teeth, while adults have 32 teeth, of a permanent nature.. Their morphology is based on the following keys:

• Dental enamel: a tissue formed by hydroxyapatite, the hardest in the entire human body. It corresponds to the outermost part of the tooth.
• Dentin: mineralized and resistant tissue, but less resistant than enamel. It is an intermediate tissue that accounts for most of the volume of the dental organ.
• Dental pulp: loose connective tissue that is surrounded by the dentin.
• Periodontium: the tissue that surrounds 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 room in communication with the outside that has 5 walls. The anterior wall is formed by the lips, the muscular gateway to the digestive tract. These muscular tissues are also essential for communication, both oral and gestural, and for the demonstration of affection and bonding in humans (and other animals).

Beyond the more visual area of the mouth, humans have 2 lateral walls (cheeks), a lower wall (the floor of the mouth and tongue), an upper wall (palate) and a posterior wall (isthmus), which communicates the mouth proper with the pharynx.

3. Oral flora

You didn't expect this last point, did you? As has been demonstrated many times in recent years, without the bacteria in our body we are nothing. Therefore, we must dedicate these last lines to those microbial agents that make our life easier and that, unfortunately, sometimes complicate it in an inordinate way.

However much the term "flora" is used, it is more appropriate to speak of microbiota or microbiome, as this term refers to the set of microbial agents that make our lives easier and that, unfortunately, sometimes complicate them in an inordinate way.This term refers to the set of colonies of microorganisms that live as commensals or symbionts in any tissue of our body, in this case, the oral cavity. The word "flora" is used to facilitate communication and disclosure, but bacteria have nothing to do with the Plantae kingdom, so its use is erroneous.

The human mouth is one of the most colonized parts of the body (along with the intestine), as it is in (along with the intestine), since it is in continuous contact with the outside world. Hundreds of species of bacteria, viruses and fungi live here. The ecological balance maintains itself in healthy individuals, but immunosuppressed conditions 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 secondary disease in the mouth.

Among the more than 700 species that live in our oral cavity, the following genera are of particular interest Streptococcus (soft tissues, saliva and tongue), Actinomyces (supragingival and infragingival level) or Veillonella parvula y Neisseriadetectable in all oral tissue. Apart from these commensal microorganisms, which do not cause any type of disease, there are other bacteria that compromise the health of the oral apparatus: Streptococcus mutans (S. mutans) and Porphyromonas gingivalis (P. gingivalis) are usually the main suspects in periodontal diseases.

Summary

We have covered a lot of ground slowly but surely, but we have left a lot of peculiarities of the mouth behind. Talking about such a utilitarian cavity (eating, digesting, expressing, speaking and tasting, among other things) is a real challenge, as each of the fronts it covers would serve for the writing of a book on its own.

The central idea of this space, if it is possible to extract one, is the following: it is not correct to conceive the organs and structures of our body as "watertight mechanisms". Surely, no matter how much you think you know a structure, you will be surprised by the thousands of accessory functionalities it has if you do enough research. In the human body, maximization of resources is a priority, so it is difficult to find structures that are "only good for one thing". The mouth is a clear example of this.

Bibliographical references:

• Berner, J. E., Will, P., Loubies, R., & Vidal, P. (2017). Physical examination of the oral cavity. Ibero-Latin American Cutaneous Medicine, 44(3), 167-170.
• Cruz Quintana, S. M., Díaz Sjostrom, P., Arias Socarrás, D., & Mazón Baldeón, G. M. (2017). Microbiota of oral cavity ecosystems. Cuban Journal of Stomatology, 54(1), 84-99.
• Guijarro, J. B., Moreno, M. G., & Iruela, I. R. BUCAL PATHOLOGY.
• Ovallos, C. D. D. D., & Cespedes, J. C. S. (2015). ANATOMICAL PARTICULARITIES OF THE ORAL CAVITY IN USERS WITH SPECIFIC CHARACTERISTICS. Revista Científica Signos Fónicos, 1(3), 101-113.
• Sologuren, N. (2009). Anatomy of the airway. Rev chil anest, 38, 78-83.