Modern man knows a lot about how his body functions. But it is worth remembering that in addition to large vital systems, there are small organs and glands. They are located throughout the body and play a significant role in the general condition of the body. An example is the lacrimal canals, from which the state of the eyes depends.
What is iron?
A gland is an organ that consists of secretory cells. It serves to produce specific substances of various chemical nature. Iron can remove the secret produced to the outside or into the internal environment of the body. As an example of these organs, we can cite the human lacrimal canals, endocrine glands, and pancreas.
The organs that remove the secret to the outside are called exocrine. The glands that produce synthesized secretion into the circulatory or lymphatic system are called endocrine.
Lacrimal glands of the person. Location
Look for lacrimal glands should be just below the upper outer edge of the orbit. Especially under them in the frontal bone a lacrimal fossa was formed in the form of a shallow indentation. To prevent iron from moving, there are fibrous cords, that is, supporting the muscles of the eye and eyelids, they are additionally retained by fatty tissue. On average, in an adult, these organs are 10x20x5 mm in size. One iron weighs no more than 0.8 g.
Structure
In its structure, the lacrimal gland is alveolar-tubular. It is formed by two unequal shares:
- orbital, which is located on top and slightly larger in volume;
- palpebral, which is called the lower lobe.
Between the lobes in which the lacrimal fluid is produced, the aponeurosis of the muscle responsible for the rise of the upper eyelid is located. From each of them there are 5-6 ducts. Gradually they are combined into one large duct.
The lower part of the gland has a gate. Arteries and veins pass through them, supplying the organ with blood, lymphatic vessels and the main duct of the gland, in which all the small lacrimal ducts converge. The lumen of the duct is open in the conjunctiva. Its exit is on the outside, about 5 mm from the extreme point of the upper eyelid. Sometimes there is a departure of additional excretory tracts. These small ducts also end in the conjunctival arch. With some ducts, the lacrimal fluid is excreted into the temporal area of the conjunctiva, some into the outer corner of the palpebral fissure. When a person closes his eyes, tears flow down the back of the eyelids, where the tear stream is located, and through a tear lake enter the small holes on the edges of the eyelids.
The upper duct, which runs next to the orbit through the bone fossa, is called the lacrimal sac. Its walls give rise to numerous paths along which tear fluid flows.
The lower part of the lacrimal gland lies in the subaponeurotic area under the lower eyelid. It consists of numerous connecting lobes. Usually there are 25-30 of them. All ducts coming from the lobules are discharged into the main gland.
In the bone base of the external wall of the nasal cavity, a large nasolacrimal duct passes. This lacrimal canal opens into the nasal cavity with a special gap in the region of the lower conch. The gap is covered by a valve from the folds of the mucous membrane.
Functions
The lacrimal glands produce a special fluid secret, which has many functions:
- removal of foreign bodies and dirt from the eye;
- protection against drying out of the surface;
- nutrient delivery to the conjunctiva and cornea;
- refraction of light;
- lubrication during eyelid movement;
- antibacterial protection.
What is a tear?
Lacrimal fluid is a transparent transudate that accumulates in serous (protein) cavities. In the chemical composition of tears, coincidences with the composition of blood are observed. However, they have a higher concentration of potassium and fluorine and a lower content of organic acids. The chemical composition of tears responds to the state of the body and is constantly changing.
The basis of the tear fluid is water. Salt (1.5% NaCl), albumin (0.5%), and mucus are dissolved in it. In the study, it exhibits a slightly alkaline reaction. Tears can be reflexive and emotional. In the first case, the body uses the secreted tear to moisturize and cleanse the eye. In the second case, to relieve tension and anxiety. Secretory cells of the lacrimal glands produce a small amount of a psychotropic substance that can bring relief in stressful situations. In a state of despair, tear stress hormones leucine enkephalin and prolactin appear. Happy tears reduce the amount of adrenaline that rises sharply with overexcitation. In addition, secretory cells provide the presence of immunoglobulins, numerous proteins, amino acids, enzyme substances, urea and other chemical elements in the tear fluid.
Since now you can roughly imagine what tear fluid is, you understand that the ability to cry is very important for a person. Tears are not only a sign of increased emotional background, but also an assistant to our eyes, preserving their health.