1 synonym for axon: axone. The synapse (article) | Human biology | Khan Academy The marked ganglia are located near, but not in, the spinal cord. Neurons are specialized nerve cells that have the ability to transmit impulses. The fourth, the Schwann cells, are found only in the peripheral nervous system (PNS). For instance, lets suppose that excitatory synapses are made on two different dendrites of the same postsynaptic neuron, as shown below. It cannot make proteins and other macromolecules and is Why are the neurotransmitter molecules cleaved so fast in the synaptic cleft ( 50molecules/ms)? Kendra holds a Master of Science degree in education from Boise State University with a primary research interest in educational psychology and a Bachelor of Science in psychology from Idaho State University with additional coursework in substance use and case management. In some cases, neurotransmitter can also be "mopped up" by nearby glial cellsnot shown in the diagram below. The axon hillock and initial segment have a number of specialized properties that make them capable of action potential generation, including adjacency to the axon and a much higher density of voltage-gated ion channels than is found in the rest of the cell body. If you're seeing this message, it means we're having trouble loading external resources on our website. Kendra Cherry, MS,is the author of the "Everything Psychology Book (2nd Edition)"and has written thousands of articles on diverse psychology topics. More broadly, they lack the versatility, flexibility, and capacity for signal modulation that we see in chemical synapses. These are to: Integrate incoming signals (to determine whether or not the information should be passed along). You can find out more about our use, change your default settings, and withdraw your consent at any time with effect for the future by visiting Cookies Settings, which can also be found in the footer of the site. The relationship of these glial cells to the structure of the CNS is seen in Figure 12.11. Like the thermostat in an air conditioner, the axon hillock will only turn on if its threshold is reached. They are electrically active and release chemical signals to target cells. Solved Match each description with the correct part of a The dendrites are usually highly branched processes, providing locations for other neurons to communicate with the cell body. Branches of axon 2. Microglia are the cells in the CNS that can do this in normal, healthy tissue, and they are therefore also referred to as CNS-resident macrophages.