Pineal Gland – Definition, Location & Function – Human Anatomy | Kenhub

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!