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An axon can divide into many branches called telodendria (Greek for 'end of tree'). At the end of each telodendron is an axon terminal (also called a terminal bouton or synaptic bouton, or end-foot). [20] Axon terminals contain synaptic vesicles that store the neurotransmitter for release at the synapse. This makes multiple synaptic connections ...
Axon terminals (also called terminal boutons, synaptic boutons, end-feet, or presynaptic terminals) are distal terminations of the branches of an axon. An axon, also called a nerve fiber, is a long, slender projection of a nerve cell that conducts electrical impulses called action potentials away from the neuron's cell body to transmit those ...
The axon hillock is the last site in the soma where membrane potentials propagated from synaptic inputs are summated before being transmitted to the axon. [2] For many years, it was believed that the axon hillock was the usual site of initiation of action potentials —the trigger zone .
Axon branches retract in a distal to proximal manner. The axonal contents that are retracted are thought to be recycled to other parts of the axon. The biological mechanism with which axonal pruning occurs still remains unclear for the mammalian central nervous system. However, pruning has been associated with guidance molecules in mice.
The area in the axon that holds groups of vesicles is an axon terminal or "terminal bouton". Up to 130 vesicles can be released per bouton over a ten-minute period of stimulation at 0.2 Hz. [ 1 ] In the visual cortex of the human brain, synaptic vesicles have an average diameter of 39.5 nanometers (nm) with a standard deviation of 5.1 nm.
An autapse is a synapse in which the axon of one neuron transmits signals to its own dendrite. The general structure of the dendrite is used to classify neurons into multipolar, bipolar and unipolar types. Multipolar neurons are composed of one axon and many dendritic trees.
Myelinated axons only allow action potentials to occur at the unmyelinated nodes of Ranvier that occur between the myelinated internodes. It is by this restriction that saltatory conduction propagates an action potential along the axon of a neuron at rates significantly higher than would be possible in unmyelinated axons (150 m/s compared from 0.5 to 10 m/s). [1]
As an action potential (nerve impulse) travels down an axon there is a change in electric polarity across the membrane of the axon. In response to a signal from another neuron, sodium- (Na +) and potassium- (K +)–gated ion channels open and close as the membrane reaches its threshold potential.