The human body is an amazing system in which work does not stop even for a split second.
And often the normal functioning of the whole organism can depend on the performance of a small organ.
You can safely rank the pituitary gland in this category.
general information
The pituitary gland is an organ, a gland, which, although small in size, is very important in the body. The task of the pituitary gland is to control the secretion of many hormones. If this gland ceases to perform its functions, the growth and development of a person will stop, all metabolic processes, the possibilities of the reproductive and reproductive systems will disappear, the psycho-emotional condition. Consequences - humanity will not be able to exist.
The pituitary gland is in charge of many of the processes necessary for human existence. Its place is at the base of the brain, exactly where the sphenoid cranial bone is located. This place is special, a bone pocket with the term "turkish saddle». The depression itself is called the pituitary fossa.
To protect this organ from pathological effects, there is a reliable protection on top in the form of a solid process of the brain membrane.
This is considered a “seat” diaphragm with an existing hole in the middle. This structure allows you to connect with the funnel of the hypothalamus of the diencephalon, and this is important, since they are - an indivisible part of a single system that allows you to take care of the work of other glands located in the body person.
The hypothalamus is needed so that the nervous and endocrine systems can work calmly. It also synthesizes hormones and then regulates their activity by the pituitary gland.
Numerous venous sinuses surround the pituitary gland.
The pituitary gland is very small:
- anteroposterior, that is, sagittal, can vary depending on the size of a person, therefore it has from 6 to 13 mm. When examining people with a height above 2 m, the size may be up to 16 mm;
- upper inferior, coronal shows data from 6 to 8 mm;
- has such parameters transverse, axial, transversal - from 3 to 5 mm.
Weighs no more than 0.5 grams. Doesn't belong to the brain.
Since this small organ is essential for the functioning of the whole organism, during development of the fetus, it is already formed by the 5th week of pregnancy, but its development continues for a long time time. However, the stage of puberty will end, the development of the pituitary gland will stop. In infants, as a rule, the percentage of this gland is less than in adults.
In the embryo, the pituitary gland begins as follows. Leadership belongs to the front lobe. This process occurs due to an epithelial protrusion that occurs in the dorsal wall of the oral cavity. If you follow the entire formation, it turns out that this finger-like outgrowth reaches the area located in zone III of the ventricle. There, in the near future, there will be a merger with the not yet formed rear lobe. It will form after some time, but it will arise in a completely different place - from the process of the funnel of the diencephalon.
Anatomy of the main gland
The pituitary gland, another name for the gland, has two main lobes. Their ratio is very unequal: one takes up almost 80 percent of the total volume.
The most solid is the anterior, called the adenohypophysis. In fact, these are miniature glandular endocrine cells of various types. Subdivided into the following parts:
- distal. It has a large territory. This is where the important work takes place - irreplaceable hormones are produced;
- tubular. It starts from the distal part, then bends around the pituitary stalk. Formed by a shell. Its effect on the body has hardly been studied;
- intermediate. Location between part of the distal and posterior lobes.
Working without pathologies of the anterior lobe becomes important especially during growth, sexual activity, as well as lactation or when a person is in a stressful situation.
A positive reaction occurs due to the release of peptide hormones that act on certain organs. First of all, these are the genitals, liver, bones, thyroid and adrenal glands. The hypothalamus controls the work of this lobe.
The posterior, small lobe is called the neurohypophysis. Belongs to the endocrine system. It is believed that this part is an axonal projection of the hypothalamus, but not part of the gland. This part contains:
- neurons, nervous lobe. Here, ependyma cells and axons are involved, or rather, their endings. They belong to the neurosecretory cells of the paraventricular and supraoptic nuclei of the hypothalamus. It is here that the synthesis of vasopressin, which is necessary as an antidiuretic hormone, and oxytocin occurs. They are transported by nerve fibers in order to get into the posterior lobe in this way. After active accumulation in the neurosectorial vesicles, they begin to enrich the blood with themselves. The lack of the required percentage of vasopressin in the body can cause diabetes insipidus, that is, the inability to control the amount of urine. In this case, the body secretes 15 - 20 liters of urine per day;
- funnel. Its task is to connect the nerve lobe with the median eminence. In conjunction with the hypothalamic funnel, the pituitary stalk is formed.
However, there is also an intermediate lobe, which is considered not so important, but is responsible for the sufficient level of melanocyte-stimulating hormone of some others. This is the thinnest layer of cells that is located between the two lobes. It is quite deep in the pituitary stalk.
Pituitary gland nutrition
This organ is also supplied with blood, like many others. However, this process occurs mainly along the anterior pituitary artery. It belongs to the internal carotid artery, which has a whole capillary network. This system passes into the venous trunks, which encircle the pituitary stalk, supplying blood to both the pituitary gland and the adenohypophysis. Divided into sinusoids, the veins from the adenohypophysis have blood that is saturated with the required amount of hormones.
The posterior lobe is nourished by the posterior pituitary artery. Additional blood is supplied by other arterial branches. Scientists still have not come to a consensus why the lobes have different sources of blood supply.
There are many differences in the shares. They even receive signals in different ways:
- the front receives them from parvocellular neurons;
- back - from magnocellular.
How an important organ works
The pituitary gland has the most important place in the endocrine system. And this is quite deserved, because it is she who produces important hormones, taking care that human life is not threatened by pathological processes.
The merit of the pituitary gland is that there are such hormones in the body:
- somatotropin. It is necessary not only during growth. Thanks to him, metabolic processes such as protein, carbohydrate and mineral are carried out, protein biosynthesis occurs. The imbalance of these hormones leads to the fact that a lack of it stuns growth, and too much causes gigantism. It is produced throughout life, but in different proportions. The highest concentration is observed until the important process of puberty has begun, and then the level growth hormone invariably falls, as a result of which cardiovascular diseases can occur, develop atherosclerosis. This hormone breaks down fat cells, fighting overweight, helps in the production of collagen, preventing rapid aging, and increases the elasticity and firmness of muscles, bone strength;
- prolactin. It is necessary so that the immune system can protect the body from inflammation, damage to the skin heals faster, and pathological processes do not arise in the adrenal glands. This hormone is involved in the rejection reaction that occurs after organ transplants. This fact allows you to warn of the negative consequences of such operations. But the most significant is the hormone during lactation, contributing to the appearance of breast milk. In women, it stimulates the growth of the mammary glands and maintains vital activity in the ovary of the corpus luteum. For men, prolactin is also necessary, supporting sexual function, controlling the level of testosterone and sperm, and in the prostate gland, it stimulates the production of secretions.
The importance of organ work
Many hormones produced by the pituitary gland help a person to continue the race, being responsible for sexual and reproductive systems, affect the behavior of people and support organs and systems, blocking the development of many diseases.
The pituitary gland helps maintain heat metabolism and metabolism, controls the production of nutrients and their a certain level, regulates the production of red blood cells, helps to adapt to new conditions, adapting organism.
If the work of the pituitary gland is disrupted, it is necessary to undergo a series of examinations. First of all, these are tests, checking the hormonal level.
For example, a large amount of pituitary hormones may indicate an adenoma. In this case, an MRI examination will be required.
During the treatment of some diseases, it is enough for the patient to undergo a course of hormonal therapy, sometimes surgical intervention is necessary.
Most often, the disease depends on a certain hormone and on its level. And because the small pituitary gland is responsible for numerous organs and tissues, the list of diseases is long. But still, the pituitary gland maintains all functions, and a person must take care of his body.
