Thursday the 22nd
Terms
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- synapse
- a region where nerve impulses are transmitted and received, encompassing the axon terminal of a neuron that releases neurotransmitters in response to an impulse, an extremely small gap across which the neurotransmitters travel, and the adjacent membrane of an axon, dendrite, or muscle or gland cell with the appropriate receptor molecules for picking up the neurotransmitters.
- sensory neuron
- a nerve cell that conducts impulses from a sense organ to the central nervous system.
- Schwann cell
- a cell of the peripheral nervous system that wraps around a nerve fiber forming the myelin sheath.
- synaptic end bulb
- bulbs located at the end of the dendrites, sends the neurotransmitters into the synapse
- nodes of Ranvier
- area of the axon that is not covered in myelin sheath between schwann cells
- Nissl bodies
- granular bodies of variable size that occur in the cell body and dendrites but not the axon of neurons, are composed of RNA and polyribosomes, are stained with basic dyes, and give a striped appearance to the cell
- postsynaptic neuron
- neuron responsible for receiving the signal
- presynaptic neuron
- neuron responsible for sending a signal
- Action Potential
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-An electrical signal that propagates along the membrane of a neuron or muscle fiber(cell); a rapid change in membrane potential that involves a depolarization followed by a repolarization.
-Also called a Nerve Action Potential or Nerve Impulse as it relates to a neuron
-And a Muscle Action Potential as it relates to a muscle fiber. - Axon
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The usually single, long process of a nerve cell that propagates a nerve impulse toward the axon terminals.
-Axon literally means the axis.
-The Axon of a nerve is the appendage that comes out of the nucleus and ends with the axon terminals - Axon Hillock
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-Cone shaped elevation of a nerve that attaches the Axon to the cell body.
-The area attached to the nucleus on one side and the initial segment on the other. - Axoplasm
- The cytoplasm of an axon
- Axolemma
- Plasma membrane of an axon
- Axon Collateral
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-The side branches along the length of an axon.
-They are typically at right angles to the axon. - Axon Terminal
- The end the axon is divided into many fine processes called axon terminals or telodendria.
- Dendrite
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-(little trees)
-The receiving or input portions of a neuron.
-Short, tapering, and highly branched.
-In many neurons they form a tree-shaped array of processes extending from the cell body.