Summary of Functions of Principal Parts of the Brain

TABLE 14.2 Summary of Functions of Principal Parts of the Brain PART BRAIN STEM Medulla oblongata mmummhlmwflmmm Pons mnm mwuwm m Midbrain FUNCYION Medulla ablangata: Contains sensory (ascending) and motor (descending) tracts. Cardiovascular center regulates heartbeat and blood vessel diameter. Medullary respiratory center (together with pons) regulates breathing. Contains gracile nucleus, cuncate nucleus. gustatory nucleus. cochlear nuclei, and vestibular nuclei (components of sensory pathways to brain). Inferior olivary nucleus provides instructions that cerebellum uses to adjust muscle activity when learning new motor skills. Other nuclei coordinate Vomiting, swallowing, sneezing. coughing, and hiccupping. Contains nuclei of origin for vestibulocochlear (VIII), glossopharyngeal (IX), vagus (X), accessory (XI). and hypoglossal (XII) nerves. Reticular formation (also in ports, midbrain, and diencephalon) functions in consciousness and arousal. Pans: Contains sensory and motor tracts. Pontine nuclei relay nerve impulses from motor areas of cerebral cortex to cerebellum. Contains vestibular nuclei (along with medulla) that are part of equilibrium pathway to brain. Pontine respiratory group (together with the medulla) helps control breathing. Contains nuclei of origin for trigeminal (V). abducens (VI). facial (VII). and vestibulocochlear (VIII) nerves. Midbruin: Contains sensory and motor tracts. Superior colliculi coordinate movements of head, eyes. and trunk in response to visual stimuli. Inferior colliculi coordinate movements of head, eyes. and trunk in response to auditory stimuli. Substantia nigra and red nucleus contribute to control of movement. Contains nuclei of origin for oculomotor (III) and trochlear (1V) nerves.