PSYC 2030 Lecture Notes - Lecture 12: Neuroglia, Multiple Sclerosis, Myelin
29 May 2018
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PSYC 2030 Lecture 12 Notes
Introduction
Impulses
• Much as home electrical wire is insulated, some axons are encased in a myelin sheath, a
layer of fatty tissue that insulates them and speeds their impulses.
• As myelin is laid down up to about age 25, neural efficiency, judgment, and self-control
grow (Fields, 2008).
• If the myelin sheath degenerates, multiple sclerosis results: Communication to muscles
slows, with eventual loss of muscle control.
• Supporting these illios of ere ells are spidery glial ells glue ells.
• Neurons are like queen bees
• On their own they cannot feed or sheathe themselves. Glial cells are worker bees.
• They provide nutrients and insulating myelin, guide neural connections, and mop up
ions and neurotransmitters.
• Glia also plays a role in learning and thinking.
• By hattig ith euros they partiipate i iforatio trasissio ad eory
(Fields, 2011, 2013; Miller, 2005).
• In more complex animal brains, the proportion of glia to neurons increases.
• A postorte aalysis of Eistei’s rai did ot fid ore or larger-than-usual
neurons
• It did reeal a uh greater oetratio of glial ells tha foud i a aerage Alert’s
head (Fields, 2004).
• The Neural Impulse Neurons transmit messages when stimulated by signals from our
senses or when triggered by chemical signals from neighboring neurons.
• In response, a neuron fires an impulse, called the action potential
• A brief electrical charge that travels down its axon
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