Unit 4

• Nervous System-it starts with an individual nerve cell called neuron
• how does a neuron fire?
• resting potential: slightly negative charge 
• reach the threshold when enough neuron-transmitters reach dendrites
• go into action potential (firing)
• The All or None Response: the idea that either the neuron fires or it does not not-no part way firing. 
• ex. firing a gun
• Types or Neurotransmitter
• Acetlycholing (ACH): deals with motor movement and memory. Lack  of ACH has been linked to Alzheimer's disease
• Dopamine: deals with motor movements and alertness. Lack of dopamine has been linked to  Parkinson's disease. Too much has been linked to schizophrenia.
• Serotonin: involved in mood control. Lack of serotonin has been link to clinical depression
• Endorphin: involved in pain control. Many of our most addictive drugs deal with endorphin.
• Drugs can be...
• agonist-make neuron  fire
• antagonist: stop neural firing
•   re-uptake inhibitors - block neurotransmitters from entering the neuron
• Norepinephrine:  helps control alertness and arousal. An under supply can lead to depression. AN over supply can lead to manic symptoms.
• GABA (gamma-aminobutytic acid):major inhibitory neurotransmitters. An under supply can lead to tremor.
• Glutamate: major excitatiry neurotransmitter; involved in memory. Oversupply can overstimulate the brain leading to migraines(This is why some people avoid MSG in food)
• Types Neurons
• sensory neurons(afferent Neurons): take information from the senses to the brain
• inter neurons: take messages from sensory neurons to other parts of the brain or to motor neurons.
• motor neurons(efferent neurons): take information from the brain to the rest of the body.