![]() (Fields, 17) Also referred to as "vesicles" and “transport vesicles.”Ĭell Body: the enlarged portion of a neuron containing the “nucleus.” (OxfordMed) Involved in important housekeeping functions such as storing genetic material and making proteins and other molecules that are necessary for the cell’s survival. The wavelength of green light is ten times longer than the size of a synaptic vesicle. Vesicles from the transmitting cell fuse to its membrane, releasing regulator chemicals by “exocytosis” into the “extracellular fluid." (Norton Lectures, 6/2/09) So finely miniaturized is the cellular structure of the nervous system that the length of a wave of visible light is too blunt to probe it. Produced by the “endoplasmic reticulum,” the “golgi apparatus,” and the cell membrane. They transport substances through, into, and out of the cell. (Chudler, 15) Characterized by a single “phospholipid” membrane. This action releases neurotransmitters into the synaptic (cleft). The membrane of the vesicle fuses with the membrane of the terminal. At the synapse, an electrical impulse triggers the "migration" of vesicles. (The Brain-Leslie Iversen, 76) Contain neurotransmitters. The vesicles serve to protect the transmitter molecules from “enzymes” inside the terminal that would otherwise destroy them. There may be thousands of synaptic vesicles in a single terminal. (GHR) Contain from 10,000 to 100,000 molecules of a specific type of neurotransmitter. Synaptic Vesicles: small secretory vesicles that contain a neurotransmitter, are found inside an axon near the presynaptic membrane, and release their contents into the “synaptic cleft” after fusing with the membrane. Presynaptic Membrane: membrane on the transmitter-output side of a synapse. (Patestas, 30) Also referred to as ‘terminal,’ ‘nerve terminal,’ ‘synaptic terminal,’ ‘presynaptic terminal,’ ‘presynaptic knob,’ ‘end foot,’ ‘terminal bouton,’ and ‘bouton terminaux.’ (LeDoux, 40) At its terminus the axon may “arborize,” forming numerous axon terminals which permits a single axon to make synaptic contact with numerous other neurons, muscle cells or gland cells. (NCIt) The point at which the sending neuron communicates with receiving neurons. (Ramachandran, 9) Contains neurotransmitters in synaptic vesicles. (Kandel, 64) Enables communication with other neurons. (Kandel, 80)Īxon Terminal: tiny end of each branch of an axon. This balance of ions maintains the stable “resting membrane potential” of 70 millivolts. The inside of the membrane becomes lined with negative charges from “proteins” (inside the cell) attempting to draw potassium ions back into the cell. The outside surface of the cell membrane becomes lined with positive charges from the potassium ions that have diffused out of the cell. ![]() Since potassium is a positively charged ion, its movement out of the cell leaves the inside surface of the membrane with a slight excess of negative charge. Contains special openings, known as “ion channels,” that allow "potassium" “ions” to flow from the inside of the cell, where they are present in high concentrations, to the outside, where they are present in low concentrations. (Kolb, 79)Īxon Membrane: the membrane that surrounds the axon. (Patestas, 30) Also referred to as ‘collaterals.’Īxon Hillock: juncture of the (neuron cell body) and axon. (Doidge, 53) Also referred to as ‘fiber,’ ‘nerve fiber,’ ‘process,’ and ‘cell process.’Īxon Collaterals: branches that diverge from the main axon at right angles. Often compared to wires because they carry electrical impulses at very high speeds (from 2 to 200 miles per hour) toward the dendrites of neighboring neurons. (The Brain-Charles Stevens, 15) A living cable of varying lengths (from microscopic up to six feet long). ![]() Provides the pathway over which signals can travel from the cell body, sometimes over long distances to neurons in other parts of the brain, and in the nervous system. Extends away from the body of the neuron. (LeDoux, 42) A critical part of the neuron. The result is that messages sent out from one cell can affect many others. However, each axon branches many times before it ends, allowing a single neuron to spawn many terminals. (Kandel, 64) Most neurons have only axon. Often splits into one or more branches along its length. (The Brain-Francis Crick, 132) Emerges at one end of the cell body and can extend up to several feet. (Goldberg, 39) Long fiber of the neuron, often with thousands of contact points. (LeDoux, 40) A protrusion emanating from the cell body that along with another neuron’s “dendrite” makes possible the connections between neurons. (Ramachandran, 9) Axons are "output" channels and dendrites are "input" channels. The axon’s function is to send data out of the cell. A projection from the neuron "cell body” that can reach long distances in the brain. Axon: one of the three main (components) of the neuron.
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