This Is Your Brain

Intro to PsychClass #2 1/30/14

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The Nervous System

Intro to Psych Class #2 1/30/14

• Central Nervous System– Brain & Spinal Cord

• Peripheral Nervous System– All other nerves in the

body– All branch off from the

spinal cord

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The Nervous SystemWhat does it DO?

It controls EVERYTHING!

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The Nervous SystemHow does the message “take a step” get from

your brain to your foot?

NEURONS!

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Neurons

• Your brain has about 1,000,000,000,000 neurons

• Different types of neurons: – Sensory neurons: “That’s hot!”– Motor neurons: “Take a step”– Interneurons: connect one neuron to another

• Intensity: demonstrated by number of neurons firing & how fast/slow they’re firing

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Neurons

• Cell Body – Main part of the neuron (may also be called soma)• Dendrites – collect the signals from other neurons• Axon – transmits the signal to other neurons• Myelin Sheath – fatty cells wrapped around the axon• Axon Ending – Very end of the axon; electrical signal converts to chemical message and

passes on to next neuron

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Neurons• Synapses – gap between the axon end of one neuron and the dendrite of the

next neuron; messages pass through here• Neurotransmitter – chemical message released across the synaptic gap to

connect to the next neuron

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Neurotransmitters

• What makes someone feel “drunk”?• What makes someone feel “high”?

NEUROTRANSMITTERSDrugs and alcohol affect the process of neurotransmission and cause the

chemicals of the brain to react differently than normal, causing someone to feel “high” or “drunk” or also to fall down, fall asleep, slur their words, etc

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Your Brain

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Phineas Gage & the metal rod

• 25 year old railroad worker• Clearing boulders by packing gunpowder using

a large metal rod• A spark ignited the gunpowder, causing the

metal rod to shoot up into Gage’s left cheek, go through his forebrain, and come out the top of his skull

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Phineas Gage & the metal rod

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Phineas Gage & the metal rod

• Gage survived another 12 years, but was a different man after the accident

• Before: friendly, popular, hardworking• After: ornery, irresponsible, disliked, a bully

But why did he change???????Physical brain damage or psychological damage?

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Your Brain

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Your Brain

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Lefties vs Righties!

• How left or right handed are you?1. Which hand do you normally use to write with?2. Which hand would you use to throw a ball at a target?3. Which hand do you use to hold your toothbrush?4. Which hand do you use to hold a knife when cutting food?5. With which hand do you hold a hammer when hitting a nail?6. When you thread a needle, which hand holds the thread?

About 77% of people are strongly right or left handed

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Lefties vs Righties!

“Left handed people are in their right mind”Kinda…

Right hemisphere does control the left hand, but the dominant hemisphere, the one that

produces language, may be on the opposite side

The trick is in the way you write…

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Lefties vs Righties!

Lefties who write with a hooked hand & righties who write straight are usually left-brain dominant

Righties who write with a hooked hand and lefties who write straight (like me!) are usually right-brained dominant