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11 Cards in this Set
- Front
- Back
- 3rd side (hint)
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The Neuron A.K.A. Neurone B.K.A. The Nerve Cell |
-A neuron is a cell that carries electrical impulses. Neurons are the basic units of the nervous system. Every neuron is made of a cell body (also called a soma), dendrites and an axon. Dendrites and axons are nerve fibers. -An electrically excitable cell that communicates with other cells via specialized connections called synapses. It is the main component of nervous tissue. |
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Classes of Neurons: |
Afferent Neurons- carry information from tissues and organs into the central nervous system. Efferent Neurons- transport signals from the central nervous system to the effector cells. Interneurons- connect neurons within the central nervous system.
By Function Sensory Neurons- carry signals from sense organs to the spinal cord and brain. Relay Neurons- carry messages between sensory or motor neurons and the central nervous system (CNS). Motor Neurons- carry signals from the CNS to muscles, motor neurons are connected to the relay neurons. The signal passes between the neurons via synapses. |
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Neurotransmitters |
Chemical molecules used by the nervous system to transmit messages between neurons, or from neuron to muscle fiber or glands. Released at the end of a nerve fiber by the arrival of a nerve impulse, & by dispersing across the synapses, it causes da transfer of that impulse to a new nerve fiber or other structure. |
The bodies chemical messenger! |
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Nerve Fiber |
The Axon of a Neuron. Carries electrical signal away from the Soma to the Synaptic Terminals. |
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Dendrites |
This is the post-synaptic branch-like receiving extension part of the Neuron. |
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Soma |
1) the cell body 2) the body of an organism |
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Axon |
the long threadlike part of a nerve cell along which impulses are conducted from the cell body to other cells. |
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Myelin Sheath |
The insulating covering that surrounds an axon with multiple spiral layers of myelin, that is discontinuous at the nodes of Ranvier, and that increases the speed at which a nerve impulse can travel along an axon. — called also medullary sheath. |
Medullary Sheath |
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Synapses |
A synapse is a complex membrane junction or gap (the actual gap, also known as the synaptic cleft, is of the order of 20 nanometres, or 20 millionths of a millimetre) used to transmit signals between cells, and this transfer is therefore known as a synaptic connection. Although axon-dendrite synaptic connections are the norm, other variations (e.g. dendrite-dendrite, axon-axon, dendrite-axon) are also possible. A typical neuron fires 5 - 50 times every second. |
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Voltage Information |
Every neuron maintains a voltage gradient across its membrane, due to metabolically-driven differences in ions of sodium, potassium, chloride and calcium within the cell, each of which has a different charge. If the voltage changes significantly, an electrochemical pulse called an action potential (or nerve impulse) is generated. This electrical activity can be measured and displayed as a wave form called brain wave or brain rhythm. |
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What R the key parts to a neuron? |
Dendrites- branch-like extensios that recieve the electro-chemical signals and send it to the Soma.
Soma- the cell body, round, contains the nucleus, life force of the nerve cell.
Axon- aka Nerve Fiber- the long thread like part that carries that signal away from the Soma to the synapses. Myelin Sheath- plasma like insulating cover for Axon. Speeds up the action potential for the signal. . Synaptic Terminals- the ending of a presynaptic neuron where the electric signal is converted into a chemical signal. At the synaptic terminal (the presynaptic ending), an electrical impulse will trigger the migration of vesicles containing neurotransmitters toward the presynaptic membrane. The vesicle membrane will fuse with the presynaptic membrane releasing the neurotransmitters into the synaptic cleft. |
Presynaptic Ending |
