The Brain, Neurons and Brain Chemistry
Each of the billions of neurons in the nervous system communicate with one another and with other cells, such as muscle cells, through special junctions known as synapses. Some neurons share synapses with thousands of other cells. Others connect with only a few cells.
In some cases, instead of binding to the receiving neuron, neurotransmitters simply float (diffuse) away from the synapse. Other neurotransmitters are broken down or degraded by enzymes found within the synaptic cleft. Many neurotransmitters are transported, whole, back into the neuron that released them. Some drugs, such as cocaine and fluoxetine (Prozac®), exert their effects by interfering with the removal of neurotransmitters from the synapse.
Sometimes, neurons do not communicate through neurotransmitters. Instead, an electrical charge passes directly from neuron to neuron through what is known as an electrical synapse. This type of signaling, in which the communicating neurons are very close together, is very fast and allows many interconnected neurons to fire at the same time. Electrical synapses are less common than chemical synapses, but they are very important for the normal development and function of the nervous system.
Keywords: brain | chemical messenger | drugs | electrical signal | neuron | neuron firing | neurotransmitters | synapse | synaptic gap
- Illustration © Baylor College of Medicine\M.S. Young.
- From the Brain Chemistry Teacher’s Guide activity, “Neurotransmitters Contain Chemicals.” Brain Chemistry Teacher’s Guide © Baylor College of Medicine (ISBN: 978-1-888997-45-3) was supported, in part, by funds from the National Institutes of Health, Science Education Partnership Award grant number R25RR13454, and the NIH Blueprint for Neuroscience Research Science Education Award, National Institute on Drug Abuse and NIH Office of the Director, grant number 5R25DA033006.
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Funded by the following grant(s)
NIH Blueprint for Neuroscience Research Science Education Award, National Institute on Drug Abuse, and NIH Office of the Director
The Learning Brain: Interactive Inquiry for Teachers and Students
Grant Number: 5R25DA033006
Filling the Gaps: K-6 Science/Health Education
Grant Number: 5R25RR013454