The oral cavity, the anatomy of which will be considered in our article, is a “borderline” organ between the surrounding and internal environment of a person. It creates a serious barrier to microorganisms, providing the initial stage of digestion and the appearance of sounds.
Oral cavity: anatomy in ontogenesis
During human embryonic development, the oral cavity begins to develop already on the 12th day. Visually, it is a protrusion of the ectoderm, which is located between the cardiac protrusion and the cerebral bladder. During this period, it is called the fossa, or oral cavity.
The tongue develops at 4-5 weeks of ontogenesis. Together with the masticatory muscles, it is the result of a modification of the gill arches. Further development of the oral cavity, the anatomy of which is much more complicated, allows the fetus to taste the taste of amniotic fluid. This is the environment in which he is located. At the 7th week, taste buds appear on the tongue. By the beginning of the second month of embryo development, the formation of the sky is completed.
Features of the mucous membrane
The anatomy of the oral cavity (photo shows its structure) is represented by the following components: lips, tongue, cheeks, teeth, gums, ducts of the salivary glands, palate and tonsils.
An important role in ensuring its functions is played by the mucous membrane formed by a multilayer flat epithelial tissue. Under it are the basement membrane and submucosal layer. A characteristic feature of the epithelium of the mouth is a high ability to regenerate, which is carried out due to its germ layer, as well as resistance to the negative effects of infections and environmental irritants.
The mucous membrane itself is formed by connective tissue cells. It is in it that the nerve endings, capillary and lymph vessels are located. The mucosa itself has specialized cellular structures that perform the most important functions. These include macrophages, mast and plasma cells. They provide phagocytosis of foreign particles, regulation of permeability of blood vessels, synthesis of immunoglobulins.
In the mucous membrane of the mouth are various types of receptors. These include pain, tactile and temperature. But the mucous does not perceive the taste. This function is performed by the muscular organ of the oral cavity - the tongue.
As a result, we can say that the mucous membrane of the human oral cavity provides protective, sensitive and plastic functions.
Tongue
Anatomy of the human oral cavity provides the formation of taste sensations. They arise when various chemicals act on specialized receptors. Agree, the perception of taste is purely individual. But scientists distinguish its main varieties. These include sour, bitter, sweet and salty.
Taste receptors are called chemoreceptors. They are located in the taste buds, each of which is connected with the mouth opening at times. Despite the general construction plan, they are all specialized. So, at the tip of the tongue are concentrated receptors that perceive sweet, at the edges - sour, at the root - bitter. More extensive is the area capable of perceiving a salty taste. It is located at the tip and around the edges. The tongue also takes part in the formation of sounds, wetting, mixing and swallowing food.
Anatomy of the oral cavity and teeth
The mechanical processing of food is carried out using teeth. Normally, there are 32 of them. In the holes of each jaw there are 4 incisors, 2 canines, 4 small and 6 large molars. All of them are specialized. So, with the help of incisors and fangs, food is bitten off, and with the help of indigenous ones it is already crushed to a mushy state.
According to the features of the external structure in the tooth, the root, neck and crown are distinguished. The latter is its visible part and is located above the gum. The fabric that covers the crown is called enamel. It is considered the hardest in the human body. The neck is formed by a less durable substance - cement. The connective tissue filling the cavity of the tooth is the pulp. It contains nerve fibers, lymphatic and blood vessels. Therefore, it is due to the pulp that nutrition and tooth growth occur.
How do these oral structures form? The laying of teeth occurs in the embryonic period. But they appear 6 months after the birth of the baby. There are a total of 20. They are dairy, replaced by permanent ones for up to 10 years. The last to grow wisdom teeth, which appear at 25 years old. For humans, they are atavism, because they lost their significance in the course of evolution.
Receptors
Scientists claim that about 2,000 taste buds are located in the oral cavity. In response to food intake, they become irritated. The signals that are formed in this way are sent through nerve fibers through the intermediate to the specialized section of the cerebral cortex. Here, a sense of taste is formed.
For all people, it is truly individual. Taste is determined by the threshold of sensitivity. For different chemicals, it is not the same. This is the highest for the bitter, low for the sour. But salty and sweet people perceive the same way.
Chemical processing of food
The anatomy of the oral cavity and pharynx is such that they are also a kind of reservoir for the primary breakdown of food. Directly food, its image or even smell stimulate the release of saliva. This happens with the help of glands, the ducts of which open into the oral cavity. With the help of saliva, complex carbohydrates are broken down into simple ones, neutralization of microorganisms, moisturizing and enveloping the food lump. Then, with the help of his tongue, he is pushed to the throat, moving into the esophagus and stomach.
Saliva composition
According to the physical properties, saliva is a colorless liquid of mucous consistency. More than 98% of its contents are water. The breakdown of complex sugars is provided by saliva enzymes - maltase, amylase and lysozyme. The latter substance also performs a protective function, neutralizing pathogens and healing the wounds of the oral cavity.
Saliva also contains mucus called mucin. It provides moisturizing and enveloping food. Thus, both the mechanical and chemical processing of food is carried out by the oral cavity. The anatomy of this section of the digestive system is completely interconnected with the functions performed.
How salivation occurs
The process of salivation occurs reflexively. To start it, irritation of the receptors of the oral mucosa is necessary. As a result of this, nerve impulses arise, which are subsequently sent to the salivary center of the medulla oblongata. Such a process is unconditionally reflex.
But if we just imagine a sour lemon or a fragrant cake, then saliva will immediately begin to stand out in the oral cavity. Such irritants are conditional.
So, the oral cavity, the anatomy of which was considered in our article, performs the following functions:
- determination of the quality and taste of food;
- mechanical and chemical processing of food;
- body protection from pathogens, low-quality products;
- the formation of a food lump;
- splitting complex carbohydrates into simple ones.