The pons in humans measures about 2.5 centimetres (0.98 in) in length. Most of it appears as a broad anterior bulge rostral to the medulla. Posteriorly, it consists mainly of two pairs of thick stalks called cerebellar peduncles. They connect the cerebellum to the pons and midbrain.
Within the pons is the pneumotaxic center consisting of the subparabrachial and the medial parabrachial nuclei. This center regulates the change from inhalation to exhalation.
The pons is implicated in sleep paralysis, and may also play a role in generating dreams.
The pons is in the brainstem situated between the midbrain and the medulla oblongata, and in front of the cerebellum. The pons can be broadly divided into two parts: the basilar part of the pons (ventral pons), and the pontine tegmentum (dorsal pons).
During embryonic development, the metencephalon develops from the rhombencephalon and gives rise to two structures: the pons and the cerebellum. The alar plate produces sensory neuroblasts, which will give rise to the solitary nucleus and its special visceral afferent (SVA) column; the cochlear and vestibular nuclei, which form the special somatic afferent (SSA) fibers of the vestibulocochlear nerve, the spinal and principal trigeminal nerve nuclei, which form the general somatic afferent column (GSA) of the trigeminal nerve, and the pontine nuclei which relays to the cerebellum.
Basal plate neuroblasts give rise to the abducens nucleus, which forms the general somatic efferent fibers (GSE); the facial and motor trigeminal nuclei, which form the special visceral efferent (SVE) column, and the superior salivatory nucleus, which forms the general visceral efferent fibers of the facial nerve.
The functions of these four cranial nerves (V-VIII) include regulation of respiration, controls involuntary actions, sensory roles in hearing, equilibrium, and taste, and in facial sensations such as touch and pain, as well as motor roles in eye movement, facial expressions, chewing, swallowing, and the secretion of saliva and tears.
Central pontine myelinolysis is a demyelination disease that causes difficulty with sense of balance, walking, sense of touch, swallowing and speaking. In a clinical setting, it is often associated with transplant or rapid correction 7 of blood sodium. Undiagnosed, it can lead to death or locked-in syndrome.
↑ Henry Gray (1862). Anatomy, descriptive and surgical. Blanchard and Lea. pp. 514–. Retrieved 10 November 2010.
Pritchard, TE & Alloway, D (1999). Medical neuroscience. Hayes Barton Press. ISBN 978-1-59377-200-0.
Butler, AB & Hodos, W (2005). Comparative vertebrate neuroanatomy: evolution and adaptation. Wiley-Blackwell. ISBN 978-0-471-21005-4.
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