The brainstem is the brain anatomical structure
that links different parts of the central nervous system:
the forebrain, the cerebellum and the spinal cord.
The brainstem plays a vital role in the many essential functions
that its nuclei regulate
such as breathing and heart rate
and even Consciousness.
It is also a passageway to sensory and motor pathways
and a pain control center
The brainstem represents the emergence area
of most cranial nerves
We distinguish three parts of the brainstem :
the midbrain, the pons and the medulla
The midbrain or "mesencephalon"
is the area of the brainstem
that is directly connected to the forebrain
through the cerebral peduncles
behind these two peduncles
we find the tegmentum
with a hole in back side
the cerebral aqueduct
Also known as the aqueduct of Sylvius
it connects the 3rd to the 4th ventricle
on the back of The midbrain is the tectum
with four colliculi
where lie the reflex centers
involving hearing and vision
The Pons "AKA the pons Varolii"
is the middle part of the brainstem
It plays an important role in motor functions
with its relay position
between the forebrain and the cerebellum
it also contributes to autonomous functions
and facial sensitivity
it containes the core and the emergence of the trigeminal nerve
The Pons is connected to the cerebellum
by the middle cerebellar peduncle
It delimits the front face of the 4th ventricle
The medulla oblongata is the portion of the brainstem
between the pons and the spinal cord
The medulla contains the olivary
and a pair of pyramids that contain
the corticospinal fibers of the pyramidal tract
The medulla contains vital autonomic control centers
for functions such as breathing, heart rate
and many reflex functions
vomiting, coughing, sneezing, and swallowing
It ends at the bottom by the pyramidal decussation
a crossing region of the corticospinal fibers