1. Neurons and Neurotransmitters

2. Nervous System Central nervous system (CNS): Brain Spinal cord
Peripheral nervous system (PNS):
Sensory neurons
Motor neurons (somatic and autonomic)

3. The Nervous System The Nervous System Central Nervous System (CNS)
Peripheral Nervous System (PNS)
Brain
Spinal Cord
Motor Neurons
Sensory Neurons
Somatic Nervous System
voluntary movements via skeletal muscles
Autonomic Nervous System
organs, smooth muscles
Sympathetic
- “Fight-or-Flight” responses
Parasympathetic
- maintenance

4. Divisions of the autonomic nervous system
Rest
Action
Figure 3.20 on page 89
The sympathetic division of the nervous system prepares the body for action, whereas the parasympathetic returns it to a resting state.

5. The Nervous System A physical organ system like any other
2 main kinds of cells
Neurons
Glia

6. Neurons Basic units of the nervous system
Receive, integrate, and transmit information
Operate through electrical impulses
Communicate with other neurons through chemical signals
More about neurons and neuronal anatomy later

7. Glial cells 100 billion neurons 10x more glial cells Glial cells
Support neurons (literally, provide physical support, as well as nutrients)
Cover neurons with myelin
Clean up debris
“Housewives”

8. Three main types of neurons
Sensory Neurons
Interneurons
Motor Neurons

9. The Withdrawal Reflex Figure 2.5B from:
Kassin, S. (2001). Psychology, third edition. Upper Saddle River, NJ: Prentice Hall.

10. Neuron Anatomy and Neural Communication

11. Dendrites of another neuron
Neurons
Cell Body
Dendrites
Axon
Myelin Sheath
Dendrites of another neuron
Axon of another neuron

12. Neural Anatomy Dendrite Axon
the bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body
Axon
the extension of a neuron, ending in branching terminal fibers, through which messages are sent to other neurons or to muscles or glands

13. Neural Anatomy and communication
Synapse
junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron
tiny gap at this junction is called the synaptic gap or cleft
Synapse movie

14. Specific Parts: The Neuron Structure
Figure 2.6 from:
Kassin, S. (2001). Psychology, third edition. Upper Saddle River, NJ: Prentice Hall.
Source:

15. Specific Parts: The Neuron Function1. 3. 2.
Figure 2.6 from:
Kassin, S. (2001). Psychology, third edition. Upper Saddle River, NJ: Prentice Hall.
Source:
Neurons = 3 functions: Reception, Conduction, Transmission

16. Action Potential
When dendrites stimulated, the delicate balance is altered
Membrane breaks down
Positively charged ions rush in (depolarization)
Charge = less negative
Causes release of chemicals from terminal buttons

17. Relay Race Action Potential starts at dendrite Through cell body
Down Axon
Axon Terminals
How does it get to the next cell’s dendrites?
Neurons don’t touch
Synapse = millionth inch gap
In synapse = vesicles w/ neurotransmitters
Chemical messengers that transmit info

18. Myelin Sheath Fatty material made by glial cells Insulates the axon
Allows for rapid movement of electrical impulses along axon
Nodes of Ranvier: gaps in myelin sheath where action potentials are transmitted
Multiple sclerosis is a breakdown of myelin sheath
Speed of neural impulse Ranges from 2 – 200+ mph

19. Myelinization clip
Myelin conduction clip

20. Neurotransmitters
chemical messengers that traverse the synaptic gaps between neurons
when released by the sending neuron,
neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether it will generate a neural impulse

21. Neurotransmitters (>60)
Acetylcholine (ACh)
1st substance identified as NT
Links motor neurons and muscles (contract or relax)
e.g. curare vs black widow spider
Also involved in memory, learning, sleep, dreaming
(acetylcholine movie)
Endorphins (the brain’s own morphine)
1973 injected rats with morphine
Bound like NTs
Brain had receptors for exogenous substance?
Brain must produce its own morphine
Released during pain and discomfort

22. More neurotransmitters
Receptor binding movie