Lacrimal fluid - what is it and what does it serve?
Modern man knows a lot about how his body functions. But it is worth remembering that in addition to the major vital systems, there are small organs and glands. They are located throughout the body and play an important role in the general state of the body. An example is tear ducts, on which the state of the eye depends.
What is iron?
Iron is an organ that consists of secretory cells. It serves to develop specific substances, different in chemical nature. The iron can excrete the secret outward or into the internal environment of the body. As an example of these organs can be the tear ducts of man, endocrine glands, pancreas.
The organs that secret outward are called exocrines. The glands that produce a synthesized secret into the circulatory or lymphatic system are called endocrine.
Tear glands of a human. Location
Search for lacrimal glands should be just below the upper-outer edge of the orbit. Especially for them in the frontal bone formed a tear well in the form of a shallow notch. To ensure that the iron does not move, there are fibrous strands, that is, supporting the muscles of the eye and eyelids, in addition they are retained by fatty tissue. On average, in an adult, these organs have dimensions of 10x20x5 mm. One iron weighs no more than 0.8 g.
In its structure, the lacrimal gland is alveolar-tubular. It is formed by two unequal shares:
- orbital, which is located on top and a little more in volume;
- palpebral, which is called the lower lobe.
Between the lobes in which a lacrimal fluid is produced, aponeurosis of the muscle responsible for the lifting of the upper eyelid is located. From each of them goes 5-6 channels. Gradually they are united in one large channel.
The lower part of the gland has a gate. Arteries and veins supplying the organ with blood, lymphatic vessels and the main duct of the gland pass through them, in which all small tear ducts meet. The lumen of the duct is open in the conjunctiva. Its outlet is on the outside, approximately 5 mm from the extreme point of the upper eyelid. Sometimes there is a detachment of additional output routes. These small ducts also end in the arch of the conjunctiva. Some ducts tear fluid is excreted into the temporal part of the conjunctiva, some - into the outer corner of the eye gap. When a person closes his eyes, tears flow down the posterior sides of the eyelids, where a tear stream is located, and through a teary lake enter small holes at the edges of the eyelids.
The upper duct, which runs along the eye socket along the bone fossa, is called a lacrimal sac. Its walls give rise to numerous paths through which a tear fluid flows.
The lower part of the lacrimal gland lies in the subaponeurotic area below the lower eyelid. It consists of numerous connecting lobules. Usually there are 25-30 of them. All ducts from the lobes are excreted into the main gland.
In the bone base of the outer wall of the nasal cavity there is a large nasolacrimal duct. This tear duct opens into the nasal cavity with a special slit in the area of the lower shell. The gap is covered by a valve from the fold of the mucous membrane.
Tear glands produce a special liquid secret that has many functions:
- removal of foreign bodies and dirt from the eye;
- protection against surface drying;
- delivery of nutrients to the conjunctiva and cornea;
- refraction of light;
- grease during the movement of the eyelid;
- antibacterial protection.
What is a tear?
Lacrimal fluid is a transparent transudate that accumulates in serous( protein) cavities. In the chemical composition of tears there are coincidences with the composition of the blood. However, in them the concentration of potassium and fluorine is higher and the content of organic acids is lower. The chemical composition of tears reacts to the state of the body and is constantly changing.
The basis of the lacrimal fluid is water. It dissolved the salt( 1.5% NaCl), albumin( 0.5%), mucus. In the study, it exhibits a slightly alkaline reaction. Tears can be reflex and emotional. In the first case, the body uses a tear released to moisturize and purify the eye. In the second case - to alleviate tension and anxiety. Secretory cells of lacrimal glands produce a small amount of psychotropic substance that can bring relief in stressful situations. In a state of despair, tears occur in the stress hormones leucine-enkephalin and prolactin. Happy tears reduce the amount of adrenaline, which increases dramatically when overexcited. In addition, secretory cells provide the presence of immunoglobulins, numerous proteins, amino acids, enzymatic substances, urea and other chemical elements in the composition of the tear fluid.
Because now you almost imagine what a teardrop is, you understand - the ability to cry is very important for a person. Tears are not only a sign of heightened emotional background, but also an assistant to our eyes, preserving their health.