Cells as building blocks
● Two types of cells in CNS
○ Glial Cells: “Glue” cells of Myelin sheath
■ facilitate neural transmission (like insulation)
■ Neurons: Nerve cells; receive, integrate, and transmit neurons
Sensory & motor (moving your body) neurons
● Efferent - away (Sensory neurons)
● Afferent - coming in (Motor neurons)
Sensory receptors in skin goes through affluent -> interneuron -> section of spinal cord ->
efferent -> bicep muscles - muscle contracts
Right motor cortex controls right side of body
Structure of Neurons
● soma - nucleus
● Axon - Myelin sheath
● Synapse - Terminal button
Overview of the action potential:
we forget to learn more
Frontal lobes go crazy when you first start to learn. you become an expert when they stop
working a lot during activity.
Resting potential of a neuron
● inactive resting state
● More negative charge inside membrane
○ Due mostly to negatively charged proteins. (A-)
● More positive charge outside membrane
○ 10x more sodium (Na+) outside than inside membrane
● Resting state of a neuronal membrane: negative charge inside; positive charge outside
● Changes from other neurons accumulate in the neuron
● once charge become sufficiently positive (reaches threshold; depolarization), they
change the permeability of the membrane, and anA.P. occurs as an all-or-none response
Action Potential Over time
1. Resting: all channels closed
2. A.P.(Action Potential): sodium channels open (depolarization)
3. Novocane shut these sodium channels and thereby blocks action potential (numbing area) Return to resting state: potassium channels open (repolarization)
4. Refractory period - return to resting potential
Every neuron communicates in this way:
● Synaptic Vesicles - Axom sent down, creating impact, jumpstarts action potential. Sent
down this into presynaptic neuron
○ Tiny sacs in the terminal buttons that contain neurotransmitters.
● Presynaptic neuron
● Action potential stimulates the chemicals into the terminal button.
● Postsynaptic neuron - Underneath the terminal button
● Channels receive neurotransmitters from postsynaptic neuron.
● Reuptake = neuotransmitters go back up.
communication between neurons
● AP weakens (electrically) the vesicles to release neurotransmitter into synapse.
● This is a chemical, not electrical process. Kinda both.
● Each neuron releases only one combination neurotransmitter. They only do one of them.
(i.w. dopamine and epinephrine.)
● Transmitters bind to receptors in post-synaptic neuron. They hang out in soma and send
down a charge when enough builds up.
● Acetylcholine drinking sleeping, learning, memory, and muscular movement.A
decrease is a foreshadowing of diseases like..
○ alzheimers (undersupply)
○ Dementia - forgetting things. neurotransmitters stop working, so they don’t learn
or remember. The ones they do have degrade.
● Norepinephrine (term for adrenaline) alertness, attention, wakefulness, emotional
○ depression (undersupply) - seratonin is involved in this and anxiety
○ Antidepressants stimulate neural epinephrine
○ Asingle neurochemical can lead to such dramatic changes.
○ Main excitatory neurotransmitters
○ i.e. epi-pen - needed to counter allergic reactions or some other disease
○ inhibition and excitation of neurons are needed
● Serotonin, sleep, temperature regulation, aggression
○ Anxiety & Depression (undersupply)
○ Pro-social attributes
● Dopamine voluntary movement, emotional arousal, mood & pleasure
○ Parkinsons (undersupply) - muscular disorder, usually for older people, motor
○ Schizophrenia (oversupply) - Decreasing dopamine is a cure ● GABA
○ Main inhibitory neurotransmitter
○ Slows CNS function (alcohol)
○ opposite of glutamate
○ Alcohol depresses, where the brain gets shut down, which explains blackouts,
memory loss, etc. You feel uninhibited at first, which feels good.
Overview of Brain Regions
(3 major ones)
● Hindbrain/Brain stem
● Midbrain (often part of brainstem)
Anatomy of the nervous system
● Hindbrain/brainstem: survival - use them synonymously. same thing really.
● medulla: bodily functions such as heart rate and respiration (injured in comas;
● Pons: (“Bridge”): part of reticular formation & bridges (nerves) the lower &
higher levels of nervous systems
● Cerebellum (“little brain” in Latin): movement and physical coordination; timing
(as in music)
● Medulla is all