The mucosa (mucosa) is a type of biological membrane found in our body. It performs many functions, which are primarily based on the communication of the external environment with the interior of our body. How is the mucosa built and what is the role of the human body?
The mucosa(mucosa,mucosa ) is essentially made up of two layers: the epithelium and the lamina of the mucosa proper. The epithelium is the outer layer, while the lamina proper of the mucosa most often adheres to the submucosa, which stabilizes and fixes the mucosa to the substrate.
The lamina propria of the mucosa contains, among others, such elements as blood and lymph vessels, nerves, glands or smooth muscles.
Depending on the location in the body, the mucosa may have a slightly different structure and functions
Gastrointestinal mucosa
Oral mucosa
In the oral cavity, the mucosa is covered with multilayered squamous or non-keratinized epithelium. The lamina propria in the oral mucosa contains, among other things, the taste buds and the salivary glands.
The oral mucosa has different functions, such as:
- protective (the epithelium is impermeable to most microorganisms, and additional protection is provided by the produced saliva and the lysozyme it contains)
- renewing (multilayer keratinizing squamous epithelium provides a balance between the formation of new cells and "wearing out" and exfoliating the old ones)
- flavored (thanks to the presence of taste buds)
- sensory (thanks to the presence of receptors sensitive to heat, cold, touch, pain, pressure)
- resorptive (the mucosa has an exceptionally high capacity to absorb certain chemicals, such as drugs such as nitroglycerin)
The mucosa of the esophagusis lined with a multilayer squamous non-keratinized epithelium, which contains small mucous glands, thanks to which the pieces of food slide more easily.
The gastric mucosais covered with a cylindrical monolayer epithelium. In this mucosa, depending on the location, there are cells that produce hydrochloric acid and digestive enzymes, as well as cells that protect the entire mucosa againstthe harmful effects of these substances. Therefore, the gastric mucosa plays a large role in handling and digesting food, making it better absorbed. Additionally, thanks to the parietal cells of the stomach, it is possible to produce an internal factor that binds vitamin B12 and is necessary for its absorption in the further part of the gastrointestinal tract.
Small intestine mucosa- the small intestine is lined with a mucosa whose epithelium (single-layer cylindrical) forms protrusions (intestinal villi) and invaginations (intestinal crypts). Due to the fact that the mucosa of the small intestine forms numerous folds, as well as villi and microvilli, its absorption area is increased many times. In addition, cells in the mucosa of the small intestine play a role in the absorption of water, various nutrients and vitamins, the production of immune factors and mucus.
Colon mucosa
In the last section of the digestive tract, i.e. the large intestine, the mucosa creates numerous cavities (i.e. intestinal crypts) with mucus-producing cells at the bottom. The mucosa in this place is primarily responsible for the reabsorption of water, the secretion of mucus, as well as for thickening and forming fecal masses.
Urinary tract mucosa
The mucosa in the urinary tract is covered almost entirely by the transitional epithelium, the so-calledurothelium , which has characteristic umbellate cells on its surface. Urotelium is supposed to fulfill the function of "sealing" the urinary tract and making it possible to stretch them.
In the bladder, the mucosa, depending on its filling with urine, can form or smooth out folds.
Mucosa of the reproductive system
The mucosa in the male reproductive systemis covered with a single-layer cylindrical epithelium, which has a secretory function and forms cilia and microvilli. Thanks to the presence of cilia, it is possible to move the sperm cells, additionally, substances are produced that enable their maturation and maintain their viability.
In the fallopian tube, the mucosais also covered with a single-layer cylindrical epithelium. It creates numerous folds and cilia that help to move the eggs and nutrients that keep them viable.
In turnthe uterine mucosa , otherwise known as the endometrium, has a very special structure and function. It is covered with a single-layer cylindrical epithelium. This epithelium extends into the mucosa, creating glands involved in the production of secretions.
The structure of the endometrium ( endometrium ) changes throughout the menstrual cycle. The key factor is its division into a basic layer that does not change, and a functional layer that peels off cyclically.
At the beginning of the cycle, the functional layer of the mucosa is rebuilt after the end of menstruation. Then, for a dozen or so days, the endometrium swells, the glands produce abundant discharge, and the entire mucosa prepares for possible implantation of a fertilized egg. If this fertilization does not take place, the functional layer of the mucosa is is ischemic and menstruation occurs, i.e. the peeling of the entire functional layer.
It is worth remembering that the mucosa located in the cervix does not undergo such changes, but contains numerous mucous glands that produce cervical mucus. The mucosa in the vagina is lined with a multilayer squamous non-keratinized epithelium and its primary function is to protect it.
Respiratory mucosa
The mucosa in the respiratory tract, and more specifically in the nasopharynx, larynx, trachea and bronchi, is covered with multi-row epithelium. It primarily has a protective function to defend our body against harmful substances in the air. This epithelium has numerous cilia and goblet cells that produce mucus.
Dirt sticks to the mucus, and then the cilia move them to the throat cavity. In the nasal cavity, the mucosa also has an olfactory function, and is also designed to warm and moisturize the air you breathe.
The mucosa in the larynxforms vocal folds that are involved in the production of speech. As the bronchial size decreases, the height of the multi-row epithelium decreases, until it finally becomes cylindrical in the bronchioles, and then, as in the alveoli, there is a cubic epithelium.
The mucosa with the cubic epithelium forms the so-called capillary-alveolar barrier, which is primarily involved in gas exchange: oxygen inhaled with air is transported to small blood vessels, and carbon dioxide is released into the lumen of the alveoli. it is then removed as you exhale.
As you can see, the mucosa plays an extremely important role in our body. It is a certain barrier that protects us from harmful external factors, and also enables many important processes without which we would not be able to function properly.