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What is the Pineal Gland and what does it do?

Updated on September 13, 2012

The pineal gland - what on earth is it?

We all have one. We all need one. We all use one everyday and yet many of us have never heard of this tiny organ in the brain.

The pineal gland is a reddish colour the size of a grain of rice and belongs to the endocrine system of the body. The endocrine system is basically the group of glands and their secretions that regulate, well just about everything in your body. The secretions from the endocrine system are chemical messengers called hormones. There are hundreds of different hormones that travel around the body but they will only interact and affect the cells or system they are designed to respond to. The endocrine system and hormones are responsible for numerous functions such as:

  • Mood
  • Growth and development
  • Metabolism
  • Cell and tissue functioning
  • Preparing the body for 'fight or flight' and other instincts such as hunger, sex, thirst etc.
  • Sexual development and regulation through all life phases - puberty, child rearing, menopause.
  • The process of reproduction
  • The ageing process
  • Activating or inhibiting the immune system
  • The regulation of other hormones

The glands are the place where the hormones are made, stored and converted for excretion.

The Pineal Gland

The pineal gland is perhaps the smallest gland but, working alongside the hypothalamus it also has several important functions:

  • It secretes a hormone called melatonin that regulates our natural or circadian rhythm.
  • It acts like a light receptor allowing the body to respond to the light and darkness of the day and the seasons.
  • The gland carries out other endocrine functions such as converting signals from our nervous system into the chemical signals of the endocrine system.
  • The pineal gland also plays a part in regulating sexual development.
  • Is important for proper functioning of the immune system
  • Assists with the metabolism of sugars.

The pineal gland, circadian rhythms and the biological clock are all closely connected.
The pineal gland, circadian rhythms and the biological clock are all closely connected. | Source
The pineal gland is one of many glands that are found in the body.
The pineal gland is one of many glands that are found in the body. | Source

The 6 basic rhythms harmonising with day and night

Sleeping and waking
darkness & daylight
(1)Cortisol secretion
highest at dawn
Intellectual performance
at its peak about noon
Body temperature
highest in the afternoon
(2)Prolactin secretion
highest at night
secreted at night
(1)Cortisol controls blood pressure & heart function
(2)Prolactin controls development and lactation of the breasts prior to and after childbirth

The pineal gland and melatonin

Melatonin is an important hormone in the body and is produced by the pineal gland. As stated earlier this chemical messenger helps to regulate our natural, or what is known as, our circadian rhythms.

The Circadian Rhythms

These are our mental, physical and behavioural changes that take place over every 24 hour period. Human beings are not the only living things who have these cycles. In addition to animals, microscopic life forms and plants also have these internal cycles. There is also a specialised science that studies these rhythms called 'chronobiology'.

We also have biological clocks. They are not the same as a circadian rhythm but are closely related. It is our biological clock that governs and controls the circadian rhythms. These natural clocks are made up of clusters of molecules within cells throughout the body and a kind of master clock regulates all the cycles and rhythms so that they work in harmony with each other.

This master clock is located in the area of the brain known as the suprachiasmatic nucleus (SCN) that lies within the hypothalamus. The SCN is believed to contain at least 20,000 nerve cells. This section of the brain is very near the area where the optic nerves for the eyes cross over. This is very important since the pineal gland and the circadian cycles respond to the amount of daylight or lack of it entering the eye.

Therefore the circadian cycles have a very important part to play in not only adjusting to the seasons but on a daily level to help us sleep. The pineal gland produces melatonin in response to lack of daylight. This hormone makes us sleepy so prompting us to go to bed at the appropriate time. If you've ever been a night shift worker you will know that even after years of night shifts your body never really gets used to it. It has also been shown that permanent night shift workers do have a higher risk of health related problems than workers who are on regular day hours.

More about the pineal gland

Anatomy scientists have discovered that the pineal gland is more active in our bodies just prior to the onset of puberty. This activity indicates that the pineal gland is getting the body ready for the activities of an adult body in particular the maturing of the reproductive system. The pineal gland also has a vital role to play in protecting body cells from the harm done by free radicals, (these are highly unstable atoms that can damage cells).

After this intense period around puberty scientists have also noted that the pineal gland then seems to calcify but this doesn't seem to hinder the production of melatonin or other functions the gland is involved with. However, low levels of melatonin have been associated with various medical conditions such as:

  • Seasonal affective disorder (SAD)
  • Prostate cancer
  • Breast cancer

There are also environmental factors that have been found to impair the pineal gland's ability to function properly:

  • Electromagnetic radiation - this is very disturbing since most of us are exposed to power lines and other sources that give off this form of radiation.
  • Fluoride - this chemical has been a bone of contention in many countries for a long time. Some are for fluoride in the water but many are against. It has been shown however, that fluoride build up in the body specifically targets the pineal gland - this was observed by research carried out at Surrey University, UK, by Dr. Jennifer Luke. The result of this build up was to reduce the amount of essential melatonin being secreted by the gland.

The pineal gland can be affected by power lines and other modern devices.
The pineal gland can be affected by power lines and other modern devices. | Source
The pineal gland has long been associated with the spiritual side of life.
The pineal gland has long been associated with the spiritual side of life. | Source

The pineal gland as the third eye

The pineal gland has been discussed and wondered about for centuries. The Ancient Greeks believed that the pineal gland was the main route to all our thoughts. Descartes named it the 'seat of the soul'. In modern times there are many who believe that through meditation and other methods that the pineal gland can be attuned to other energies and frequencies so opening up the spiritual within us. There is no scientific proof - is there ever? - that this is the case. However, research conducted while people are meditating shows a marked increase in activity around the pineal gland while they are doing so.

It could be that this tiny little gland has many more secrets to be revealed to us - both the scientific and the spiritual. Time will tell.


Submit a Comment
  • Seeker7 profile imageAUTHOR

    Helen Murphy Howell 

    6 years ago from Fife, Scotland

    Hi Sue Adams, many thanks for stopping by and glad that you found the hub enjoyable and useful.

    The Circadian rhythms tend to respond to daylight rather than 'false light' as does the pineal gland. However, every organ in the body, including the brain and of all the glands do need proper sleep. To get proper rest this does need quiet and a darkened room. This is what stimulates the body to both heal itself and to rejeuvinate. When people regularly fall asleep with lights on and tv's playing loud can actually cause severe mood disorders such as depression and it decreases the levels of melatonin produced. Melatonin helps us to feel good. Melatonin tends to need darkness in order for it to produce more amounts. In addition having lights and tv's, computers etc on while sleeping tends to lead to a marked deterioration in general health and well being. Hope this helps.

  • Sue Adams profile image

    Juliette Kando FI Chor 

    6 years ago from Andalusia

    I learned a lot from this hub, thank you. So if you fall asleep in front of a blasting TV with all the lights left on, would that affect your Circadian Rhythms and body clock? Does the penal gland need darkness and peace to function properly or can it do its job under any circumstances?

  • Seeker7 profile imageAUTHOR

    Helen Murphy Howell 

    7 years ago from Fife, Scotland

    Hi Rosemay - I agree with you that for its size it definitely packs a punch! I think that the activation during meditation is very interesting indeed. Particularly as our ancestors gave a lot of importance to this area of the brain without the benefit of technology - how did they know about it? Another mystery maybe!

  • Rosemay50 profile image

    Rosemary Sadler 

    7 years ago from Hawkes Bay - NewZealand

    I hadn't heard of this gland but it seems to do an awful lot for its size. Interesting that the power lines and fluoride affect it and even fascinating that there is more activity during meditation, the third eye. I guess we still have a great deal to learn about ourselves.

    As always an awesome job Seeker and a lot of research involved which is always appreciated. Thank you

    You have my votes

  • Seeker7 profile imageAUTHOR

    Helen Murphy Howell 

    7 years ago from Fife, Scotland

    Hi Gypsy - always a pleasure to hear from you and glad that you enjoyed the hub many thanks as well for the share - much appreciated!

  • Seeker7 profile imageAUTHOR

    Helen Murphy Howell 

    7 years ago from Fife, Scotland

    Hi teaches12345, many thanks for stopping by and glad that you found the hub interesting.

  • Seeker7 profile imageAUTHOR

    Helen Murphy Howell 

    7 years ago from Fife, Scotland

    Many thanks annerivendell.

  • Gypsy Rose Lee profile image

    Gypsy Rose Lee 

    7 years ago from Daytona Beach, Florida

    Voted up and interesting. Thanks for this very informative and fascinating hub. Really didn't know there was this gland and what it did. Passing this on.

  • teaches12345 profile image

    Dianna Mendez 

    7 years ago

    Interesting about the power lines and fluoride affecting the pineal gland. I believe this to be true. This gland is so important in the function of our body, even though it is so small. I found you hub very interesting.

  • annerivendell profile image


    7 years ago from Dublin, Ireland

    Great Hub. Voted up

  • Seeker7 profile imageAUTHOR

    Helen Murphy Howell 

    7 years ago from Fife, Scotland

    LMAO!!!! My good friend Frank! I honestly about fell off my chair when I read your comment!! You make me laugh so much and your honesty is so refreshing!! You're not only a class A poet but a one in a million unique guy!!

    Having said all this I might just consider writing about the penis if I thought I could get the traffic in from Google - I'm assured the search numbers for this particular part of the male anatomy is astronomical. I wonder what they are all wanting to find out about???? Most of it I dare say would be far too risky for Hub Pages anyway!

  • Frank Atanacio profile image

    Frank Atanacio 

    7 years ago from Shelton

    a very good share but honestly I thought you were going to write about the penis.. aaagghhh that was embarrassing .. but none theless now I know what a Pineal Gland is and its function thank you


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