Everything about Parietal Eye totally explained
A
parietal eye, also known as a
parietal organ or
third-eye is a part of the
epithalamus present in some animal species. The eye may be photoreceptive and is usually associated with the
pineal gland, regulating
circadian rhythmicity and hormone production for
thermoregulation.
Function
The lizard-like reptile
tuatara has a "well-developed parietal eye, with small lens and retina". Parietal eyes are also found in
lizards,
frogs and
lampreys, as well as some species of
fish, such as
tuna and pelagic
sharks, where it's visible as a light-sensitive spot on top of their head. A poorly developed version, often called the parapineal gland, occurs in
salamanders. In
birds and
mammals the parietal organ (but not the pineal gland) is absent.
Physiology
The parietal eye is a part of the
epithalamus, which can be divided into two major parts; the
epiphysis (the pineal organ, or
pineal gland if mostly endocrine) and the parietal organ (often called the parietal eye, or third eye if it's photoreceptive). It arises as an anterior evagination of the pineal organ or as a separate outgrowth of the roof of the
diencephalon. In some species, it protrudes through the
skull. The parietal eye uses a different biochemical method of detecting light than
rod cells or
cone cells in a normal vertebrate eye.
Further Information
Get more info on 'Parietal Eye'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://parietal_eye.totallyexplained.com">Parietal eye Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |
