The Nervous System

I. Characteristic of The Neuron A. Directionality of Electrical Signals B. Integration C. Threshold D. Conduction Velocity E. Plasticity and Reinforcement by Use F. Substructure of a Neuron 1. dendrite 2. soma 3. axon 4. axon hillock 5. myelin sheath 6. synaptic terminals II. Neural Circuits A. PNS vs. CNS B. Sensory Receptors and Effector Organs C. Sensory fibers (input) and Motor neurons (output) D. The simple knee jerk relex arc E. Definitions 1. nuclei 2. ganglia 3. interneurons III. The Basis for the Electrical Signal - The Action Potential A. The Membrane Potential; all cells are more negatively inside B. The Resting Potential C. Na/K ATPase Pump D. Components of the Action Potential - and ionic (channel) basis 1. resting state 2. stimulus 3. depolarization 4. repolarization 5. after hyperpolarization 6. relative and absolute refraction 7. hyperpolarization (generally inhibitory) vs. depolarization (generally excitatory) E. Characteristics of the Action Potential 1. frequency of firing information 2. pattern of which circuits are reaching threshold 3. The ALL-or-NONE principle 4. Non-decrimenting signals 5. Unidirectional propagation down the axon F. Conduction Velocity 1. Increase diameter or increase myelination 2. Myelination in Vertebrates a. CNS = oligodendrocytes b. PNS = schwann cells c. Saltatory Conduction i. internode ii. Node of Ranvier IV. Synaptic Transmission A. Two forms 1. Chemical Synapses 2. Electrical Synapses B. Details of Chemical Synapses 1. Terminology a. presynaptic cell b. postsynaptic cell c. synaptic cleft d. neurotransmitters (NT) 2. Transmission of A.P. using a. voltage-gated Ca channels b. exocytosis of NT vesicles c. integration and threshold at the axon hillock 3. Excitatory NT a. glutamate (+) b. aspartate (+) c. dopamine (+) d. acetylcholine (+/- in nervous system, + in muscle) 4. Inhibitory NT a. GABA (-) b. glycine (-) c. serotonin (-)