Oral cavity, the anatomy of which will beis considered in our article, is a "boundary" organ between the environment and the inner environment of a person. It creates a serious barrier to microorganisms, providing an initial stage of digestion and the appearance of sounds.
During the embryonic development of the human oralthe cavity begins to develop on the 12th day. Visually, it is a protrusion of the ectoderm, which is located between the heart protrusion and the cerebral bladder. In this period it is called a pit, or mouth cavity.
The tongue develops on the 4th-5th week of ontogeny.Together with the chewing muscles, it is the result of the modification of the gill arches. Further development of the oral cavity, the anatomy of which is greatly complicated, allows the fetus to taste the amniotic fluid. This is the environment in which it 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 being completed.
Anatomy of the oral cavity (photo shows its structure) is represented by the following components: lips, tongue, cheeks, teeth, gums, ducts of salivary glands, sky and tonsils.
An important role in ensuring its functions is played byThe mucosa formed by a multilayered planar epithelial tissue. Under it are the basal membrane and the submucosa. A characteristic feature of the epithelium of the mouth is a high ability to regenerate, which is carried out due to its growth layer, as well as resistance to the negative effects of infections and environmental irritants.
Actually the mucosa is formed by cellsconnective tissue. It contains the nerve endings, capillary and lymphatic vessels. Actually the mucosa has specialized cellular structures that perform the most important functions. These include macrophages, obese and plasma cells. They provide phagocytosis of foreign particles, regulation of permeability of blood vessels, synthesis of immunoglobulins.
In the mucosa of the mouth are different typesreceptors. These include pain, tactile and temperature. But the taste does not perceive mucous. This function is performed by the muscular organ of the oral cavity - the tongue.
As a result, it can be said that the mucous membrane of the human oral cavity provides protective, sensitive and plastic functions.
Anatomy of the human oral cavity provides andthe formation of taste sensations. They occur when different chemicals are exposed to 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 connects to the mouth opening at times. Despite the general layout of the building, they are all specialized. So, the tip of the tongue concentrates receptors that perceive the sweet, on the edges - sour, on the root - bitter. More extensive is the area that can perceive the salty taste. It is located on the tip and around the edges. Language also takes part in the formation of sounds, wetting, stirring and swallowing food.
Mechanical processing of food is carried out atthe help of teeth. Normally there are 32. There are 4 incisors, 2 canines, 4 small and 6 large molars in each of the jaws. All of them are specialized. Thus, with the help of incisors and canines, food is bitten off, and by means of molars it is already crushed to a mushy state.
According to the peculiarities of the external structure in the toothdistinguish the root, neck and crown. The latter is its visible part and is located above the gum. The fabric that covers the crown is called enamel. It is considered to be the hardest in the human body. The neck forms a less strong substance - cement. The connective tissue that fills the tooth cavity is the pulp. It contains nerve fibers, lymphatic and blood vessels. Therefore, it is due to the pulp that nutrition and growth of the teeth occurs.
How do these structures form the oralcavity? Plaque of the teeth is still in the embryonic period. But they appear 6 months after the birth of the child. A total of 20. They are dairy, up to 10 years old, being replaced by permanent ones. The latter grow wisdom teeth, which appear at the age of 25. For man, they are atavism, because they lost their meaning in the course of evolution.
Scientists say that in the oral cavitythere are about 2000 taste buds. In response to food they get irritated. Signals that are formed in this case, along nerve fibers, are directed through the intermediate to the specialized department of the cerebral cortex. Here, a sense of taste is formed.
For all people it is really individual.The taste is determined by the sensitivity threshold. For different chemicals, it is not the same. The highest is for bitter, low for sour. But the salty and sweet person perceives the same.
Anatomy of the oral cavity and pharynx is such that theyare also a kind of reservoir for the primary splitting of food. Directly the food, its image or even the smell stimulates salivation. This happens with the help of glands, the ducts of which open into the mouth. With the help of saliva, complex carbohydrates are decomposed into simple, neutralizing microorganisms, moisturizing and enveloping the food lump. Then, with the help of the tongue, he pushes to the pharynx, advancing into the esophagus and stomach.
According to the physical properties of saliva is acolorless liquid mucous consistency. More than 98% of its content is water. Splitting of complex sugars is provided by saliva enzymes - maltase, amylase and lysozyme. The latter substance also performs a protective function, detoxifying pathogens and healing the wound of the oral cavity.
Saliva also contains mucus, which is calledmucin. It provides moistening and wrapping food. Thus, both the mechanical and chemical processing of food is carried out by the oral cavity. The anatomy of this department of the digestive system is completely interconnected with the functions performed.
The process of saliva is reflexive.To "start" it is necessary to irritate the receptors of the oral mucosa. As a result of this, nerve impulses arise, which later are sent to the center of the saliva of the medulla oblongata. Such a process is unconditioned-reflex.
But if we only imagine a sour lemon or a fragrant cake, saliva will immediately start to appear in the mouth. Such stimuli are conditional.
So, the oral cavity, the anatomy of which was considered in our article, performs the following functions:
