Chapter 3

• Neuron - basic working unit of the brain, specialized cells that are responsible for transmitting nerve impulses


  Responsible for experiences through senses
• Glia - smaller but more numerous than neurons


  Other cells that support and coordinate activity between neurons, also remove waste
• ~100 Bil. neurons in the nervous system, they are found in the brain and spinal cord
• 3 Basic parts of Neurons:

  • Cell Body - contains nucleus
  • Dendrite - widely branching structures that receive input from other neurons
  • Axon - longs, thin, straight fiber that transports impulses recieved from dendrite


  Axons are insulated by Myelin Sheath which helps speed up transmission
• Neuron Pathway:

  A) Axon

  B) Myelin Sheath

  C) Dendrites

  D) Axon Terminals

  E) Nuceus

  F) Cell Body

  
• • Action Potential - the excitation that travels along the axon at a constant strength, all-or-nothing law, active voltage
  • Resting Potential - the neuron is not excited, resting voltage 


  Ex. When a light is turned on it has action potential, if its turned off then it is resting potential because it can be turned on.
• Synapses - specialized junctions between neurons
• Neurotransmitter - chemical that activates receptors on other neurons


  Chemicals can be consumed (caffeine) or natural (melatonin, hormones)
• Presynaptic Neuron - neuron that sends impulse, before the synapse

  Postsynaptic Neuron - neuron that receives the impulse after the synapse
• Synapses can cause chemicals to be processes or withheld
• Agonist - a drug that increases the activity at a synapse


  Antagonist - a drug that decreases the activity at a synapse
• Stimulants - drugs that increase energy, alertness, and activity

  Ex. - Ecstasy, Speed, Methamphetamines, Cocaine, Cigarettes, Caffeine

  Dopamine, chemical that bring happiness and relieves pain. L-dopa, chemical similar to dopamine that's used to treat Parkinsons.
• Hallucinogens - drugs that induce sensory distortions

  Ex. - magic mushrooms, Special K (Ketamine), acid
• Narcotics - drugs that produce drowsiness, insensitivity to pain, and decreased responsiveness

  Ex. - Opium, Morphine, Codeine, Heroin, Vicodin, OxyCotin


  Narcan treats narcotic overdoses
• Monism - mental activity and brain activity are inseparable

  • the mind is separate yet inseparable from the brain
  • the mind uses the brain and the brains responds to the mind
  • the mind also changes the brain