• Question: What is the importance of the pineal gland?

    Asked by snacks to Anne, Carolyn, Joe, Mariana, Nick on 22 Mar 2010 in Categories: .
    • Photo: Joseph Devlin

      Joseph Devlin answered on 22 Mar 2010:


      Well, it’s less important than Rene Descartes liked to believe! He thought it might be the key piece of anatomy that linked mind and brain because — according to Descarte — it is the only part of the brain that isn’t mirrored on both sides and everyone knows that souls are unitary and whole, not split into two halves. Turns out Descartes was a fairly poor anatomist because there are several brain structures on the midline that are not mirrored in the two hemispheres — the largest is a white matter bundle called the corpus callosum that links the two hemispheres together. If there was a single brain structure linking brain and mind/soul, it’d definitely be the corpus callosum.

      In fact, the pineal gland a small, pine-cone shaped gland located on the ventral midline of the brain which produces melatonin, a hormone that affects wake/sleep patterns. It’s part of your endocrine system which is a series of glands that produce hormones.

      How come you’re always coming up the hard Qs, Snacks?!

    • Photo: Carolyn McGettigan

      Carolyn McGettigan answered on 22 Mar 2010:


      The pineal gland is located in the midbrain, beneath all that cerebral cortex (the wrinkled mantle on the outside of the brain) and right in the midline between the two hemispheres. It’s believed to be important in using information originally received at the retina (in the back of the eye) about incoming light and using this to generate a hormone called melatonin. The amount of melatonin secreted from the gland increases during the night-time and decreases in the day, and it is thought that this helps to regulate the sleep-wake cycle in many species of animal (including us). There is some suggestion that taking melatonin supplements at your intended bed-time can overcome the effects of shift-work and jet lag. Furthermore, the pineal gland may have a role in controlling reproductive behaviour, for example in animals where this varies with the time of year, as the gland is able to monitor the relative duration of day versus night (and days become longer in the spring and summer).

    • Photo: Nick Bradshaw

      Nick Bradshaw answered on 22 Mar 2010:


      Oh dear, not something I deal with myself. I’m fairly sure it has something to do with controlling sleep cycles and also in “seasonal activity” (e.g. in animals I know it determines when it is time to hibernate).

      Hopefully the others know a bit more about this!

    • Photo: Mariana Vargas

      Mariana Vargas answered on 22 Mar 2010:


      The pineal gland produces the hormone melatonin when the eyes are not stimulated by light, and it helps set the “circadian rhythm” (such as cycles of sleep and awakeness throghout the day) in vertebrates. It is also has the extra function in birds to help them navigate their location during migration as it helps detect the magnetic field of the Earth.

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