Pineal gland

The pineal gland (synonym pineal gland, the pineal gland is a small, with a length of about 1 cm, education ellipsoidal shape located in the brain between the top of the quadruplet bodies relating to the organs of internal secretion. The pineal gland is part of the intermediate brain (epithalamica region). Consists of the dark (neuroglial) and light (pineal) cells, the emerging bands and small slices. Has a rich blood flow through the vessels of the Pia mater, which covers the pineal gland. Together with the vessels to the pineal gland is suitable sympathetic nerve fibres.
Hormones pineal body have an inhibitory effect on the development of the sex glands and their secretions, as well as on production of certain hormones crust napochechnikov (for example, aldosterone). In the case of tumors of the pineal gland in children comes premature puberty (see). Cm. also the brain.

The pineal gland [glandula pinealis; synonym: the epiphysis (epiphysis cerebri), pineal body (corpus pineale)] - small, oval-shaped body, located above Chetvorkata, reddish-gray color.
Embryogenesis. Develops the pineal gland in the form of epithelial diverticulum the upper part of the intermediate brain behind the choroid plexus, in the second month of fetal life. In the future the walls of the diverticulum thicken and ependymal pavements are formed of two parts - first front, then back. Between shares germinate vessels. Gradually Magdalena Bay tapering (from it remains only recessus pinealis), the share converge and merge into a single body. The parenchyma of the anterior lobe is formed from cells front pavements epiphyseal Bay, rear - out of secretory ependyma the back of the Bay.
Anatomy. The pineal gland is located between the valley of the front pair of cetverokatnice (Fig. 1)covered the fold of the Pia mater. On the basis of the pineal gland has recessus pinealis. The size of the pineal gland: up to 12 mm in length 3-8 mm and 4 mm in thickness. The size and weight vary with age.
Artery pineal gland depart from the choroid plexus of the third ventricle; the pineal gland is rich in nerve fibres from the rear comissary, brain bridle.

epiphysis
Fig. 1. The pineal gland (1), top view. Corpus callosum and the body removed; vascular tire III ventricle cut and drawn in hand.
the pineal gland
Fig. 2. The pineal gland of a newborn child (sagittal section;? 32): 1 - epiphyseal leg connecting with rear comissro; 2 - neuroglia; 3 - recessus pinealis; 4 - ependyma; 5 - commissura habenularum; 6 - slice (peripheral part with small cells); 7 - the Central part of wedges with a larger bright pineal cells; 8 - the tip of the pineal gland, facing backwards; 9 - connective-tissue sheath (pia mater).

Histologically, the parenchyma of the pineal gland has syncytial structure and consists of the pineal and glial cells. The pineal cells are large, bright, with large nuclei, glial - small, compact cytoplasm, hyperchromic cores, numerous processes. The size and shape of the pineal cells vary with age and in part connected with the floor (Fig. 2). To 10-15 years of life in them appears pigment (lipogram). Morphological manifestations of secretion by the pineal gland: nuclear balls - pale basophilic education inside nuclei pineal cell vacuolization of their cytoplasm, basophilic or oxytelinae drops of colloid in cells (tissue colloid) and in vessels of type venules (intravascular colloid). In stroma meet single or multiple layered spherical concretions - "brain sand", which derives colloid, in which they lay phosphates, salts of calcium and magnesium. Expansion Liaodong tissue pineal gland (Glisy) revealed a 15%, most men. Physiological involution epiphysis is characterized by hyperplasia of stremy, formation of cysts. Parenchyma is saved to a ripe old age.
Physiology poorly understood, mainly because of the small size of the pineal gland, peculiarities of its localization and plurality of the functional linkages from different parts of interstitial brain, endocrine glands and other organs. For a long time it was unclear whether the pineal gland of the endocrine in the full sense of the word. In 1958 by Lerner (Century A. Lerner) opened melatonin, so named because it causes the accumulation of melanin grains around the nucleus of melanocytes, resulting in lightening the skin of some amphibians. This discovery and subsequent experimental studies have given a reasonable basis for recognition that the pineal gland is really gland of internal secretion and its secret - melatonin. It is produced in the pineal gland in the methoxylation serotonin; is only synthesized in the pineal gland, as in no other body no enzyme oxindole-O-methyltransferase (OIMT)necessary for the synthesis of melatonin. Melatonin is secreted into the bloodstream, as found in the peripheral nerves. It affects distant organs located: changes the weight of the ovaries and violates the reproductive cycle of animals.
Tagged with radioactive isotopes melatonin is found in the ovaries, the hypothalamus, the pituitary gland. Secret pineal gland, apparently, there is a group of active substances - methoxyindole; in extracts of pineal glands along with melatonin managed to find another substance which shows a similar effect,- methoxytryptamine.
Besides the influence of secret pineal gland to sexual matters, which most researchers believed brake identified and braking action pineal gland the thyroid gland and the secretion gipofizom gonadotroponah and somatotropic hormones. Most researchers acknowledge the stimulating effect of the extract of pineal gland secretion by the adrenal cortex aldosterone.
Romanian endocrinologists [Parhon and Elko (C. Parhon, S. Milcu)] believe that the pineal gland secretes a hypoglycemic factor paneelin. They also indicate the participation of the pineal gland in mineral metabolism control (phosphorus, calcium, potassium and magnesium).
Noted the close relationship between the epiphysis and vegetative centers of interstitial brain and pituitary gland, which together constitute a single system that controls reproductive glands and growth of the body. The hypothalamus is the place for the primary application of the antagonistic effects of the pituitary gland and the pineal gland.
Melatonina activity of the pineal gland is changing synchronously with the change of the ambient light: it is the maximum at midnight and the minimum at noon. This is reflected in cyclic daily variation in weight and function of sexual glands. On Wurtman and Akselrod (R. J. Wurtman, J. Axelrod, extended coverage female rats affects their reproductive same as removing the pineal gland, and the effect of these impacts is not cumulative. According to the authors, ambient light effect on the pineal gland through the retina, the superior cervical ganglia, and from there through the sympathetic nerves, ending in the cells of the epiphysis. These studies suggest that the main function of the pineal gland is to synchronize endocrine systems in line with changing light conditions throughout the day. Epiphysis also regulates the cyclic activity of serotonin. However, this rhythm is determined by endogenous processes and does not disappear after blinding animals or by placing them in the darkness.


Pathological anatomy. Malformations: there are cases of hypoplasia and agenesis of the pineal gland. Atrophy of the epiphysis is rare, can be caused by the pressure of the tumor as the gland itself and the neighboring tissues, hydrocephalus.
Dystrophic changes in the form of protein malnutrition pineal cells are seen in infectious diseases, massive necrosis of the liver, phosphorus poisoning, leukemia. Necrobiotic changes in cells epiphysis observed in acute infections, eclampsia.
Disorders of the blood supply in the pineal gland observed arterial or venous hyperemia (on the grounds of acute infections, thyrotoxicosis, pulmonary hypertension) and hemorrhage. The latter may be associated with trauma, infection, hemorrhagic diathesis, hypertension. The outcome of hemorrhage - cysts that may occur and how the outcome of the elementary innovative necrosis foci of gliosis observed in acute infections, and tuberculous meningitis. In modified sklerozirovanie vessels epiphysis sometimes there thrombosis.
Inflammatory processes in the pineal gland is always secondary. Leukocyte infiltration and blood clots occur in the brain abscesses, meningitis, sepsis. In the epiphysis described tuberculosis granulomas, perspectices reaction (accumulation of lymphocytes and histiocytes) in tuberculous meningitis, tuberculosis of the lungs. In case of congenital syphilis in the epiphysis meet gum.
Pinealoma (pineal gland tumor) - see the brain (tumors).
Diseases of the pineal gland does not have definite symptoms. Clinic and treatment of tumors of the epiphysis - see the brain.
X-ray examination. The seventh straight x-ray of the skull epiphysis is located strictly on the middle line.
At volume of intracranial processes of different Genesis (tumours, abscesses of the brain, post-traumatic intracranial haematoma) epiphysis can be shifted from the middle line, opposite to the lesion focus. If the pineal gland this obasistiy, this symptom bias is very important for diagnosis (Fig. 3).
Clarification of topical diagnosis within hemisphere (frontal, temporal, parietal, occipital lobe) possible side radiograph on the basis of offset calcified pineal gland forward, backward, up, and down by measurements made in different ways. Decisive is the only direct (sagittal) radiograph (see the Skull).

Fig. 3. Direct x-ray of the skull. Calcified pineal gland is shifted to the left by a tumor located in the right hemisphere of a large brain.