PGY 300 Lecture Notes - Lecture 2: Myelin, Axon Hillock, Resting Potential
5 Feb 2017
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Document Summary
Reach out to get signals from outside world, other neurons, glands, muscles. Initial segment (axon hillock) - very sensitive to production of action potential (brief burst of activity) Connects to dendrites of another neuron, gland, muscle. Axon of presynaptic cell synapses dendrite of postsynaptic cell. Electrical signal goes from dendrites cell body (soma) axon synapse out. Sensory neurons/afferent neurons going to spinal cord. Motor neurons/efferent neurons that leave spinal cord. Oligodendrocytes wraps around several different neurons or several different myelin units. Surround synapse and clear out excess neurotransmitter from synaptic area. Once neurotransmitter is released to postsynaptic cell, astrocytes remove synapse so postsynaptic cell is clear for next signal. Charge - ions (na+, k+, ca++, cl-) Current - ions/sec (into or out of cell) Voltage (potential) - energy to move charge. Inside of cell is almost always negative. Conductance (1/resistance) - ease of moving charge across membrane (via channels)
