Whether an action potential occurs depends on the summation of all chemical messages. The
action potential either does or does not occur, there is not a middle ground.
The action potential is speded along by the myelin sheath, and electrically insulating material
that wraps around the axon allowing the action potential to jump from node (called nodes of
Ranvier) to node.
They are what make white matter white.
Glial cells make up the support system for neurons:
1. Astrocytes—support neurons mechanically, regulate metabolism, respond to brain
3. Microglia—dispose of debris
4. Ependymal cells—make CSF, line the ventricular system
The brain gets blood from the neurovasculature—blood vessels in the brain.
• Anterior cerebral artery
• Middle cerebral Artery
• Posterior cerebral artery
You have a right and left one of each of these.
There are four internal cavities called ventricles. They are filled with CSF.
• Govern pressure dynamics
• Chemical regulation
• Provides brain with nutrients
• Make brain buoyant
Why do we have it?
• makes the brain lighter
• also allows room for swelling or growth
We have two lateral ventricles, a third ventricle, a cerebral aqueduct, and a fourth ventricle.
Major brain regions—
o Cerebral hemispheres
o Diencephalon: thalamus, hypothalamus, pituitary
o We don’t talk about this one
• Hindbrain aka brainstem
o Medulla, pons, cerebellum
o Responsible with basic functions we need to live