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Neuroanatomy - The Brainstem

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