The 'pons' (sometimes 'pons Varolii' after
Costanzo Varolio) is a structure located on the
brain stem. It is
rostral to the
medulla oblongata,
caudal to the
midbrain, and
ventral to the
cerebellum. In
humans and other
bipeds this means it is above the medulla, below the midbrain, and
anterior to the cerebellum.
Function
It is part of the
central nervous system, and
relays
sensory information between the
cerebellum and
cerebrum. Aides in relaying messages in the brain, and contains the pneumotaxic centres that help regulate respiration. Some theories pose that it has a role in
dreaming.
[1]
Anatomy of the pons
The "knob-like" process is 2 centimeters long and located on the anterior (front) of the brainstem. It is formed of nerves that travel from one side (left or right) to the other. Most other fibres in the brainstem travel up and down.
The posterior (back) surface of the pons forms part of the wall of the
fourth ventricle of the brain.
Most blood to the pons is supplied by
pontine arteries. These are small arteries that branch off the
basilar artery (of the
Circle of Willis). Blood also comes from the
anterior inferior, and
superior cerebellar arteries.
There are two main domains in the pons for
control of respiration:
[2]
★ the
apneustic center - lower pons
★ the
pneumotaxic center - upper pons
Cranial nerve nuclei
A number of
cranial nerve nuclei are present in the pons:
★ mid-pons: The ''chief'' or ''pontine'' nucleus of the
trigeminal nerve sensory nucleus (V)
★ mid-pons: the
motor nucleus for the trigeminal nerve (V)
★ lower down in the pons:
abducens nucleus (VI)
★ lower down in the pons:
facial nerve nucleus (VII)
★ lower down in the pons:
vestibulocochlear nuclei (
vestibular nuclei and
cochlear nuclei) (VIII)
Additional images
References
1. The "Science of Dreaming" in Neurontic: Psychology for the Modern Mind..
2.
External links
★
Diagram at UCC
★