Epiphysis - what is it? Structure and function of the epiphysis

Quite often in modern medical practice, and in the scientific literature, one can come across the term "epiphysis." What it is? What are the functions of this structure? What properties does it have? These questions are of interest to many people, especially given the fact that this body is often associated with some esoteric theories.

Epiphysis - what is it?

In fact, in the human body, there are two structures that are usually designated by this term. Surely many have heard of the bony epiphysis, which is the terminal section of the tubular bones.

But in the human brain there is also an epiphysis. What it is? This is a small structure, which is usually referred to as a diffuse endocrine system. By the way, there are other names for this organ, for example, the pineal body and the pineal gland. Epiphysis of the brain is part of the so-called photoendocrine system, and, despite its relatively modest size, its role for the normal functioning of the body is simply enormous.

Epiphysis of the bone and its functions

The bony epiphysis is an enlarged ridge of the tubular bone. It is this part that represents the articular surface that forms the joint together with the adjacent bone.

In this department, bone tissue has a spongy structure. The surface of the epiphysis is covered with articular cartilage, and under the cartilaginous tissue there is a so-called subchondral plate containing many nerve endings and capillaries.

Inside, the bony epiphysis is filled with red bone marrow. This structure is extremely important for the normal operation of the human body, since it is here that the formation and maturation of red blood cells occurs.

Epiphysis (pineal body) and its location

It is worth noting that the epiphysis is the most recently discovered and least studied part of the human brain. Of course, over the past decade, many discoveries have been made, explaining the mechanism of this structure. By the way, outwardly this small organ is somewhat like a pine cone, for which, in fact, it was called the pineal gland.

This organ is located almost in the center of the brain, between the two hemispheres in the area of intertalamic fusion. It is also attached to both visual horns located in the diencephalon.

Cellular structure

Epiphysis is a small organ, painted in a grayish-red color. Outside, it is covered with a dense capsule of connective tissue. The capsule forms so-called trabeculae that penetrate the gland and separate it into small lobules. This is how the human epiphysis looks like - its structure can be considered quite simple.

The inner part of the gland consists of parenchyma and connective tissue elements. The main structural elements in the epiphysis are the pinealocytes - polygonal parenchymal cells. In addition to these, four other cell types were also detected: pineal gland neurons, interstitial endocrinocytes, peptidergic neuron-like structures, and perivascular phagocytes.

It is worth noting that at the beginning of a person's life the epiphyses grow rapidly, but approximately during the pubertal period the growth of the pineal body gradually fades. Moreover, as the human body grows older and aging, the gland involution takes place.

Main functions

Of course, the functions of the epiphysis have not yet been fully studied. Nevertheless, it is known that the main hormone of the pineal body is melatonin, which is responsible for the formation of so-called circadian rhythms (sleep and wakefulness). This hormone is responsible not only for the frequency of sleep, but also helps the body to adapt when changing time zones. And it acts as an antioxidant and slows down the aging process.

Of course, the epiphysis produces some other hormonal substances. For example, iron secretes adrenoglomerulotropin, which stimulates the synthesis of aldosterone. In addition, the epiphysis performs some other important functions. For example, it inhibits the release of growth hormones and sexual development, prevents the formation and growth of tumors, strengthens the immune system. It is believed that the hormones of the epiphysis in one way or another control the work of the hypothalamic-pituitary system, thereby affecting the work of all the glands of internal secretion of the body.

Regulation of functioning

It is worth noting that the features of the work and regulation of the epiphysis are still poorly understood. Studies are difficult due to the small size of the gland and its location. Nevertheless, it is proved that the epiphysis is controlled not only by nerve endings, but also is susceptible to light.

Of course, light does not penetrate directly to the pineal body. Nevertheless, photons irritate specific ganglion cells of the ocular retina. Hence, the nerve impulse is transferred to the suprachiasmal nucleus of the hypothalamus, from where it is sent through the paraventricular nucleus to the upper segments of the thoracic region of the spinal cord. Hence the excitation is transmitted to the epiphysis through the upper cervical ganglion. It is worth noting that the impulse arising in the suprachiasmal nucleus does not stimulate, but, on the contrary, inhibits the functioning of the pineal body. Thus, in light, the secretion of melatonin decreases, and in the dark (at night) increases. As for the stimulation of the epiphysis, the neurotransmitter in this case is norepinephrine.

Pineal gland diseases

Certainly, some diseases can affect this area of the brain. For example, often during examinations, various neoplasms are found in a structure called the epiphysis. What it is? Yes, sometimes in the tissues of the pineal body malignant cell degeneration occurs. There is a benign tumor or cyst.

Since the epiphysis is a gland of internal secretion, naturally, the hormones produced by it affect the work of the entire endocrine system. Even a small cyst of the epiphysis can lead to severe hormonal failure and the development of a disease called macrogensitis. Such a disease is accompanied by a change in the level of some hormones, which leads to premature physical and sexual development (the appearance of menstruation at an early age, etc.). Often, there is mental retardation.

Epiphysis in modern esotericism

It's not a secret to anyone that a lot of mystical stories and esoteric theories are connected with the pineal body. The fact is that this organ was discovered relatively late, and is hidden deep in the brain structures, which led some scientists and philosophers to think about the extreme importance of the epiphysis. For example, Rene Descartes in his works called the epiphysis "saddle of the soul." Indeed, it was this structure that for decades and even centuries was perceived as a kind of receptacle for the human soul.

There are more ancient beliefs about the mystical "third eye" that allows a person to see the invisible and is responsible for various extrasensory abilities. For example, in the 19th century a theory was put forward that the mysterious third eye does exist. But if in some animals it is located on the surface of the body (for example, in some cyclostomes the epiphysis does come to the surface and performs the function of a photosensor), then people's eyes "hide" inside the skull.