Pineal gland, brain tumor, melatonin, circadian rhythm

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The pineal gland is a small, pine-cone shaped, pea-sized organ that is attached by the pineal stalk to the diencephalon or midbrain. It projects backwards so that it lies behind the midbrain in the middle of the head.

Hormonal and Sleep Regulation

Hormonal and Sleep Regulation

This endocrine gland functions to influence other important hormone-producing organs in the body, including the pituitary gland the islets of Langerhans of the pancreas, the parathyroid glands, the adrenal glands and the gonads. Hormones secreted by the pineal glands reach their target organs through the bloodstream or the cerebrospinal fluid. The actions of these hormones are usually inhibitory and either directly inhibits the organ from producing the hormone or stop the hypothalamus from secreting hormone releasing factors. The pineal gland is also thought to affect the function of the immune system.

This organ is found to be most active during periods of darkness and may play a part in the body’s circadian or sleep rhythm; the hormone melatonin and the enzymes required for its production are sent to the front lobe of the pituitary gland. The pineal gland may also play an important role in regulation of reproduction function and in maintaining temperature in the body.

Shrinking or Atrophy of the Pineal Gland

In normal human development, the pineal gland starts shrinking from the age of 25, slowly losing its ability to control hormones in the body and contributing to the process of aging. This natural atrophy of the pineal gland may also cause changes in sleep patterns that are common in the elderly. There is a direct relation between this organ and the visual system as the production of melatonin is regulated by light entering the eye.

The cells in the pineal gland are called pinealocytes and glial cells. Over time and with age, calcareous deposits accumulate in the glial cells and the connective that supports them, replacing the function cells of the gland. These deposits are used in radiology images of the brain as they show up clearly and serve as a landmark.

Tumors of the pineal gland or tumors in surrounding areas that may press on it, can cause severe changes in reproductive function of the body and other disorders in mood, sleep patterns and fatigue. Prognosis and treatment of a pineal or brain tumors depends on the type, location and size of tumor, the presence or absence of metastasis, overall health, age and medical history. A cyst in the pineal gland that causes it to be compressed or unable to function properly, may cause similar symptoms.