regions of the brain: brain stem

brain stem

• attaches to the spinal cord

• parts of the brain stem

  • midbrain

  • pons

  • medulla oblongata

• reticular formation

midbrain

• below thalamus

• mostly composed of tracts (myelinated) of nerve fibers

• has two bulging fiber tracts: cerebral peduncles

• has four rounded protrusions: corpora quadrigemina

  • reflex centers for vision and hearing

    • two eyes, two ears: 4

  • inferior to thalamus and posterior to brainstem

• cerebral aqueduct

• cerebral peduncle

cerebral aqueduct

• AKA aqueduct of sylvius

• connects third ventricle to fourth ventricle

• transportation mechanism that carries CSF down

pons

• 2nd bump

• the bulging center part of the brain stem

• mostly composed of fiber tracts

• includes nuclei involved in the control of breathing (major function)

medulla oblongata

• 1st bump

• the lowest part of the brain stem

• merges into the spinal cord

• includes important fiber tracts

• contains important control centers

  • mostly cardiovascular center

    • heart rate control

    • blood pressure regulation

  • a little bit of breathing

  • CN IX and X come out of medulla oblongata

    • swallowing

    • vomiting

reticular formation

• diffuse mass of gray matter along the brain stem

• involved in motor control of visceral organs

• reticular activating system (RAS) plays a role in awake/sleep cycles and consciousness