Like all other systems, the endocrine system is a complex system, and plays an important role in various physiological and psychological functions of the body. The pineal gland is one of the important organs of the endocrine system.
For several years, the gland was considered as a vestigial organ like the appendix. However, in 1958, it was discovered that this gland secretes a hormone called melatonin.
The pineal gland is a very small gland that resembles the shape of a pine cone. It derives its name from the Latin word Pinea. It is deeply placed inside the skull, and weighs just a little more than 0.1 gram. It lies in a tiny cave-like secured place, almost in the center of the brain.
It's attached to the posterior wall of third ventricle, just behind and slightly above the pituitary gland. The gland is perfectly placed in a groove where the two cerebral hemispheres of the brain join, a little behind the root of the nose. Thus, the gland lies behind the eyes, and the place enables it to get a complete view of the area covered by the eyes.
The endocrine glands secrete hormones which are required for proper functioning of the body. The pineal gland secretes the hormone melatonin, mainly at night. Darkness stimulates this gland to release the hormone, while light inhibits secretion of the hormone. Melatonin determines the hibernation period, mating season, and seasonal reproduction of animals.
The unusual characteristic of this gland is that it is larger in small children; but its size decreases as one reaches puberty. It plays an important role in sexual development and metabolism. It is believed that when it is present in abundance in children, it inhibits the sexual growth. Pineal tumors are responsible for exceptional and early puberty.
Melatonin production is cut down with the onset of puberty. Pineal gland calcification is sometimes noticed in adults. A cyst in this gland is usually asymptomatic, but sometimes, large cysts may exhibit symptoms such as headaches, vertigo, increased sensitivity to light, visual disturbances, nausea, and vomiting.
Melatonin released by the gland determines the body weight and energy balance. More research is needed to establish the relationship between melatonin and obesity. It is responsible for the feeling of sleepiness that we experience. It converts the nervous system signals to endocrine signals.
The gland governs the biological clock of our body, as it works along with the hypothalamus. We feel thirsty and hungry, because of the signals sent by the pineal gland. It governs sexual desire, and also controls the aging process.
The pineal gland is referred to as the "third eye" of our body, since philosophers and spiritual adepts believe that the gland is the place where our soul lies, and it plays an important role in our inner vision. It acts as a mediator between the physical and spiritual world.
It triggers supernatural sensations, as it responds to the electromagnetic energy stimuli around us. According to the ancient Indian philosophy, this gland is connected with the important 'crown chakra' or the energy center, and activation of this chakra can facilitate the separation of the soul from the physical body.
The deficiency of melatonin or melatonin overdose can result in various pineal gland disorders. Working in shifts, poor vision, jet lag, etc., can affect the melatonin production, which in turn might cause insomnia. The development of tumors in this gland can lead to symptoms such as headache, nausea, vomiting, vision problems, or memory disorders.
Following natural day/night light patterns, adopting good sleeping habits, avoiding working in shifts, exercising in sunlight, leading a stress-free life, and practicing yoga and meditation techniques could help prevent disorders associated with this gland.
Disclaimer: This is for informative purposes only, and should not be used as a replacement for expert medical advice.