PSY 1101 Lecture Notes - Lecture 3: Myelin, White Matter, Actian

• School: University of Ottawa
• Department: Psychology
• Course: PSY 1101
• Professor: Kenneth Campbell

Document Summary

The axons are composed of grey and white matter depending if it is surrounded by the myelin sheath. The myelin sheath is able to speed up rate of transmission. 3 categories of neurons: sensory neurons: transmit impulses, motor neurons: carry"s outgoing signals from cns to muscles and glands c. Often far from sensory and motor neurons. Study on squids for electrical charges using electrodes require a large axon. The charge of the neuron can change. Excess of negatively charged ions inside the nerve cell. Cell membrane opens the channels: positively charged ions flow in. Changes in the charge making the cell less negatively charged (depolarization) If the level of excitation is not enough the critical threshold is not reached. When threshold is reached the neuron fires. The action potential travels down the axon. The action potential will travel down the length of the axon. The amplitude of the axon potential will not vary this is the all or none law.