BRAIN STEM- MEDULLA

Brainstem

• Performs spinal cord-like functions for the head

• Contains LMN for head muscles• Initial processing of general afferent

information concerning head

Conduit function

• Ascending tracts reach thalamus and cerebellum

• Descending tracts reach spinal cord• Many tracts do not run through straight-

frequent involvement of relay nuclei

Cranial nerve functions

• Cranial nerves are head’s equivalent of spinal nerves

• Involved in olfaction, sight, hearing, equilibrium and taste

• Olfactory → telencephalon• Optic → diencephalon

• The rest project to or emerge from brainstem• Collection of sensory and motor nuclei related

to cranial nerve function at various levels in brainstem

Integrative function

• Complex motor patterns• Regulation of cardiovascular and respiratory

activity• Some regulation of consciousness [function of

reticular formation in central core of brainstem]

Level of pyramidal decussation

Level of sensory decussation

Components of inferior cerebellar peduncle