Answer
The pons is one of the two large derivatives of the metencephalon. It is located rostral to the medulla and caudal to the midbrain. Its posterior aspect is dominated by two pairs of longitudinal bulges, the cerebellar peduncles, that connect the pons to the cerebellum and the medulla. Anteriorly, the pons presents as a broad convex mass of tissue above( superior to) the medulla. Internlly, it contains has elements of the reticular formation (RF)-- gray matter ( medial lemniscus)-- and white matter. The latter consists of transverse fibers bundles that connect right and left cerebral hemispheres, and longitudinal fascicles that transmit sensory and motor signals up and down the brain stem.
Work Step by Step
The following cranial nerves begin or end in the pons: trigeminal nerve (CN V); abducens nerve ( CN VI); facial nerve (CN VII); vestibulocochlear nerve (CN VIII).
Some of the important CNS tracts associated with the pos are the following:
A. Transverse tracts:
Corticospinal tracts : these are associated with voluntary
control of body structures
Corticobulbar tracts concerned with motor control of head
neck and face
B. Longitudinal Tracts:
Anterolateral spinothalamic-- transmit crude touch, pain and
temperature stimuli
Lateral lemniscus -- transmits auditory signals
Ventral (anterior) spinocerebellar. Decussates in the spinal
cord, and again at the level of the pons on the way to the
cerebellum--transmits proprioceptive stimuli from the body
to the cerebellum.
