What is the pineal gland?

Once called the 'third eye,' the pineal gland is a small gland located deep in the center of the brain. Named for its pinecone shape, this gland secretes melatonin, which plays a role in the body's internal clock. The pineal gland was one of the last brain organs to be discovered and has been the subject of much mythology and speculation. The seventeenth-century French philosopher Rene Descartesthought the soul was located in the pineal gland.

What is the pineal gland?

The brain is comprised of two distinct hemispheres connected by fibers.

The pineal gland is located in the middle of the brain, in between the two hemispheres.

The pineal gland contains mainly pinealocytes, which are cells that produce the hormone melatonin; and glial cells, which are a particular type of brain cells that support neurons (the cells that transmit information to other cells).

                                                                                                                                                                Understanding circadian rhythms

The pineal gland is key to the body's internal clock because it regulates the body's circadian rhythms. Circadian rhythms are the daily rhythms of the body, including signals that make someone feel tired, sleep, wake up, and feel alert around the same time each day.

The pineal gland secretes melatonin, which is a hormone that helps regulate circadian rhythms. Melatonin is produced according to the amount of light a person is exposed to.

The pineal gland releases greater amounts of melatonin when it is dark, which points to melatonin's role in sleep. Many supplement manufacturers offer melatonin as a "natural" sleep aid.

Some research, however, suggests that the link between melatonin and sleep might not be as simple as it seems. These researchers found that removing the pineal gland did not affect the activity levels of rats that had normal access to light and dark. They concluded that the function of the pineal gland may be more complicated than initially thought and that its role may vary widely between different animals.

Other functions of the pineal gland

The pineal gland has been linked to a range of other functions. These include:

Bone metabolism

Research on mice suggests that changes in the function of the pineal gland might affect bone metabolism. Postmenopausal women are significantly more vulnerable to osteoporosisthan other groups.

Pineal gland function tends to decline with age. The study concluded that oral melatonin supplements might help increase bone mass, which could be used in the future to protect against postmenopausal osteoporosis.

Mental health

Sleep and mental health are inextricably linked. Sleep deprivation can cause or worsen some mental health conditions. Some mental health disorders may also make it more difficult to sleep.

Some mental health conditions have been linked to access to light. Seasonal affective disorder, for instance, is a form of depression that affects a person's mood and tends to occur when light levels are low. This may be due to changes in melatonin secretion.

A 2017 review, however, found no evidence that melatonin had any effect on mood disorders.

Pituitary gland function

The pituitary gland is a gland that protrudes from a part of the brain called the hypothalamus. The hypothalamus is linked to a wide range of hormonal functions, including growth and thyroid function. Older research suggests that the pineal gland can alter the behavior of the pituitary gland.

Melatonin may block the pituitary gland from secreting hormones that play essential roles in the development of the ovaries and testes and regulate functions such as the menstrual cycle.

Drug metabolism

Some drugs, including both recreational and prescription drugs, appear to alter the function of the pineal gland and change melatonin secretion patterns.

One study concluded that the pineal gland could play a significant role in addiction to cocaine and other psychostimulants.

Source : Medical News Today