1. The Nervous System Your body’s communication network & control center
Peripheral Nervous System (PNS)-gathers info from inside & outside the body
Central Nervous System (CNS)-receives info & initiates response-
brain & spinal cord
NEURONS = Messengers & receivers of these transmissions

2. BASIC STRUCTURE OF NEURON
Cell body-contains nucleus & cell membrane
Dendrites-branching projections of the cell body, carry impulses into the cell
Axon-Threadlike extension carries impulses to & from the cell, at the end of axon is the axon terminal
Myelin Sheath-Insulates the axon & speeds up transmission of the impulses
Synapse-point of contact at which impulses are passed from one cell to another

4. Voluntary Actions vs Reflex Actions
Impulses passed via the brain
What is the chain of events that happens from the instant you hear the phone ring until you pick up the phone?
Every time a stimulus—such as a ringing telephone—is detected, the body's neurons send a nerve impulse through the nervous system.
If the safety of our body requires a very quick response, the signals may pass directly to a motor neuron for instant, unthinking action. This is a reflex action. Signals sent via the spinal cord

5. NEUROTRANSMITTERS chemicals released by vesicles in sending neuron
travel across the synapse and bind to receptor sites on receiving neuron
2 TYPES =
EXCITATORY = stimulate the brain, increase the likelihood that the neuron will fire an action potential
INHIBITORY = calm the brain, balance mood & are depleted when excitatory are overactive

6. Lock & Key Mechanism
Neurotransmitters bind to the receptors of the receiving neuron in a “key-lock mechanism”.

7. Neurotransmitters: Serotonin
various functions = body temp., sleep, mood*, appetite, and pain
Low levels =implicated in depression & probs with immune syst.
Stimulant medications or caffeine in your daily regimen can cause a depletion of serotonin
High = Serotonin Syndrome(mild to severe symptoms including seizures)

8. Neurotransmitters Con’t.
Norepinephrine (AKA Noradreneline)
important for attentiveness, emotions, sleeping, dreaming, and learning
Prepares you for action
causes blood vessels to contract & heart rate to increase
GABA
Gamma-Amino Butyric Acid
An inhibitory neurotransmitter 
“nature’s VALIUM-like substance”
Related probs = anxiety*, seizures, Huntington’s disease (nerve cell degeneration), sleep probs
Valium and similar antianxiety drugs work at GABA synapses

9. Neurotransmitters Con’t.
Dopamine
main focus* neurotransmitter
Affects neurons associated with voluntary movement
role in learning, memory, and emotions
Loss of dopamine-producing cells = Parkinson’s Disease*
Excess = focusing issues, less motivation, schizophrenia*
Stimulants (ex: cocaine, meds for ADD/ADHD, caffeine) cause dopamine to be pushed into the synapse so that focus is improved 
BUT cause a depletion over time
Acetylcholine
triggers muscle contraction
important role in arousal and attention
Loss = linked to Alzheimer’s Disease*

10. Neurotransmitters Con’t.
Endorphins
linked to pain control and to pleasure
Reduce pain by inhibiting or “turning down” neurons that transmit pain information
natural, opiate-like neurotransmitters “morphine within”

11. How Neurotransmitters Influence Us
Although not the sole cause of schizophrenia, dopamine imbalance is consistently seen found in patients with schizophrenia
Drugs that prevent dopamine from binding to receptors can reduce the symptoms of schizophrenia
Dopamine pathways are involved with diseases such as Parkinson’s disease
caused by a deterioration of brain neuron’s that produce dopamine (it is still unknown why this occurs)
Affects movement
Preview Question 2: How do neurotransmitters affect our mood and behavior?

12. Neurotransmitters (see pg 99)

13. A & A Neurotransmission
Agonist
Increases production
Activates the neuron receptor that it attaches to
Antagonist
Decreases production
Deactivates the neuron receptor that it attaches to

14. Agonist and Antagonist
Ex: mimic serotonin in a patient with depression
Ex: block dopamine receptors in a patient with schizophrenia

15. NPR, Savant, and Crash Course Links
Crash course Nervous System
Crash Course “Your Chemical Brain”