1. The Neuron

2. Nerves
Bundles of Axons
Same function
Phrenic nerve
Alcohol Overdose

3. Axonal Membrane of a Neuron

4. Ion Channels
Cell membrane proteins that pass ions in and out of the cell
Voltage-Gated Ion Channels
gates are regulated by membrane voltage
Chemical-Gated Ion Channels (also called Receptors)
gates are regulated by neurotransmitters
Iontotropic
fast
Metabotropic (G-protein coupled)
requires second messenger cascade
slow

5. Chemical-Gated Ion Channels
Iontotropic
Metabotropic

6. Electrochemical Gradient
Inside the Cell
More K+
Less Na+
Outside the Cell
More Na+
Less K+
Ion Flow Mantra: Na+ In, K+ out

7. Depolarization/Hyperpolarization

8. Action Potential Phases2
Rapid 3 1
Threshold 4
Phase Ion responsible Ion Channel Responsible
1. Threshold Na+ Chemical-gated Na+ channel
2. Rapid Depolarization Na+ Voltage-gated Na+ channel
3. Repolarization K+ Voltage -gated K+ channel
4. After Hyperpolarizatoin K+ Na+/K+ pumps

9. Na+/K+ Pumps After the Action Potential,
Na+/K+ pumps move Na+ ions back out of the cell and move K+ ions back into the cell
The movement is against the concentration gradient of each ion so it requires energy (ATP)
The pumps move 3 Na+ ions for every 2 K+ ions

10. Unmyelinated Propagation

11. Myelinated Propagation

12. Synaptic Action Voltage-gated Ca2+ channels Synaptic Potentials: EPSP
IPSP

13. Synaptic Potentials Excitatory Postsynaptic Potential (EPSP)
triggered by excitatory neurotransmitters
open ligand-gated Na+ channels
allows Na+ to flow inside the cell
causing a slight depolarization of the postsynaptic cell
moves the postsynaptic cell closer to firing an action potential
Inhibitory Postsynaptic Potential (IPSP)
triggered by inhibitory neurotransmitters
open ligand-gated K+ channels or Cl- channels
allows K+ to flow out of the cell or Cl- to flow inside the cell
causing a slight hyperpolarization of the postsynaptic cell
moves the postsynaptic cell further from firing an action potential

14. Brain Organization

15. Spinal Cord Anatomy Dorsal Ventral Dorsal Horn: Sensory information in
Ventral Horn: Motor information out

16. Brainstem Brainstem: arousal center (ARAS) sensory in pathway
motor out pathway
Midbrain
Superior Colliculus
Inferior Colliculus
Pons
REM sleep
Medulla
breathing center
cardiac center

17. Ascending Reticular Activating System (ARAS)
Arousal Center

18. Cerebellum Motor Coordination Fine tuning of: sensory systems emotions
learning and memory
Autism
decreased cerebellum size

19. Thalamus and Hypothalamus
relay station
Hypothalamus
regulation center

20. Nucleus Reticularis Thalami
NRT:
GABA cells
Gatekeeper

21. Hypothalamic Nuclei hunger/thirst blood pressure/heart rate
blood pressure/shivering
stress
satiety
sex
memory
reproduction
thermoregulation
reproduction
circadian rhythms

22. Limbic System Emotion Rewards Memory smell aggression fear learning
recognition memory
smell recognition?
memory

23. Basal Ganglia Movement Parkinson’s Disease cell death in
substantia nigra

24. Cortical Lobes Frontal: Strategy and Planning Motor area Parietal:
Somatosensory area
Temporal:
Audition, Language
Occipital:
Vision