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Anatomy and function of the pineal gland.
Hey everyone! This is Nicole from Kenhub, and in this tutorial, we will be discussing the pineal gland, its structure, location, function and blood supply. So we're back with our medial view/sagittal section of our brain where we can see the pineal gland which is our topic of discussion for today highlighted in green. So the pineal gland also known as the epiphysis cerebri or pineal body is a small cone-shaped structure measuring approximately five to eight millimeters long. It is located in the diencephalic part of the forebrain or prosencephalon above the quadrigeminal plate just here. And let's remind ourselves that the prosencephalon contains the thalamus and the hypothalamus amongst other things.
The pineal gland shown in the posterior view rests between the posterior aspects of the thalami here and projects posteriorly from the wall of the third ventricle just here. The pineal stalk of the pineal gland has a superior lamina and an inferior lamina, and zooming in a little to our pineal gland we can see the habenular commissure and the habenular trigone which are both part of the superior lamina. Now the habenular commissure and the habenular trigone both connect the pineal body to both cerebral hemispheres and they do so superiorly. The posterior commissure which is part of the inferior lamina connects the pineal body to both cerebral hemispheres inferiorly. And, remember, lamina means plate so if it helps you, you can imagine these little sheets connecting the pineal gland to the cerebrum.
So in this image we're looking at a really cool x-ray vision of the ventricles and we have our lateral ventricles over here and our fourth ventricle over here. And between the two laminae of the pineal stalk is a space known as the pineal recess. And the pineal recess communicates anteriorly with the third ventricle in green and the hypothalamic sulcus which lies in the lateral wall of the third ventricle.
The pineal gland is an endocrine gland that functions to produce the hormone melatonin – a hormone that affects the state of wakefulness and sleep as well as photoperiodic or seasonal functions. The pineal gland is also believed to have a reproductive function associated with the onset of puberty and it's believed that it inhibits the maturation of genitals until puberty. And it might be interesting to note that the pineal gland unlike the rest of the brain is not isolated from the body by the blood-brain barrier.
Oxygenated blood to the pineal gland is provided via fine branches of the posterior choroidal arteries which are derived from the posterior cerebral artery which we can see here in green – and here let's just point out the posterior cerebral artery coming off the basilar artery. The internal cerebral veins drain deoxygenated blood from the pineal gland joining with the basal vein of Rosenthal and the posterior mesencephalic vein to form the great cerebral vein of Galen which we can see here in green and which in turn drains to the straight sinus.
This tutorial might be over, but there are more videos you can watch related to this topic. You can also subscribe to our YouTube channel or go to our website where you'll find fun quizzes, related articles, and atlas sections – all you need to kick some gluteus maximus in anatomy and histology. I'll see you soon!