- plato though mind was in brain, aristotle thought mind was in heart
- we now understand biological/psychological connection between brain and mind
- phrenology: 1800's- Franz Gall suggested that bumps on your head represent your abilities and personality traits
- he was right that human brains are modular: different parts have different functions
Neural Communication
our information processing system is made up of neural cells
- 20 billion in brain, 100's of billions in glial cells
- glial cells support neurons
- astrocytes: provide nutrition to neurons
- oligodendrocytes and Schwann cells: insulate neurons
- they create a myelin sheath covers axon which accelerates speed of messages
- cell body: life support for neuron
- dendrites: receive messages
- axon: passes message from cell body to other neurons, muscles, glands
- myelin sheath: covers axon, provides protection and increases speed
- terminal branches of axon: goes to dendrites of other cells
- action potential: electrical charge (from ions)
- caused by pumping, flowing movement of positive ions through cell's membrane
- too much water can flush out these ions and destroy the system-- death!
- threshold= the level of stimulation required to trigger a neural response
- refractory period: after a neuron fires, there is a moment of readjustment before it can fire again
- always fires in same direction, at same intensity (toilet analogy)
- Synapse: junction between axon tip of sender and dendrite of receiver, tiny gap= synaptic gap
- re-uptake: neurotransmitters are reabsorbed into the sending neurons
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