Psychology 1000 Chapter Notes - Chapter 3: Myelin, Neurotransmitter, Axon Terminal

• School: Western University
• Department: Psychology
• Course: Psychology 1000
• Professor: Dr.Mike

Document Summary

Neurons can vary in size and shape (more than 200 different types of neurons) Glial cells: surround neurons and hold them in place; also manufacture nutrient chemicals that neurons need, form myelin sheath, and absorb toxins and waste materials. Blood-brain barrier: prevents many substances from the entering the brain. Neurons are surrounded by a salty liquid environment rich in positive sodium ions (na+) Inside the neuron, there are some positively charged potassium ions (k+), but overall there are more negative ions; thus, the inner membrane carries a negative charge. Resting potential of about -70 millivolts (mv) This resting state is said to be polarized. The action potential: sudden reversal in the neuron"s membrane voltage, during which the membrane voltage momentarily moves from -70mv to +40mv. This shift from negative to positive is called depolarization. Graded potentials: small changes that occur as a result of axons stimulating the dendrites or the cell body: proportional to the amount of incoming stimulation.