SOC221 Lecture Notes - Lecture 12: Peripheral Nervous System, Axon Terminal, Myelin
28 Jan 2017
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Document Summary
Nerves make up the peripheral nervous system. Neuron makes up one cell of the nervous system. 3 types of neurons: sensory neurons, carry information from sensory orgnas to the nervous system. A- protein molecules only exist in the intracellular fluid and have a negative charge. Action potential happens when tiny channels open up and let sodium ions in, this causes the inner charge to become positive inside. This shift is called the depolarization phase. Repolarization phase when potassium ions are pushed out and the charge becomes more negative. Myelin sheath cover the axon so that signals travel faster. The junction between each axon terminal and cell body is called a synapse. A packet of chemicals is released when the action potential reaches the axon terminal. Excitatory snynapse, the transmitter opens sodium channels on the post synaptic membrane. The movement of positive sodium in the cell is called depolarization. Inhibitory synapse, the transmitter opens chloride or potassium channels.
