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47 Cards in this Set
- Front
- Back
Neurons |
Nerve cells |
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Two types of neuron signals |
Electrical Chemical |
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Electrical signal |
Mostly within neurons |
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Chemical signal |
Between neurons (Neurotransmitters) |
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Central nervous system |
Brain and spinal chord |
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Peripheral nervous system |
Nerves that convey messages to and from the CNS |
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Information processing path |
Sensor senses stimulus Sensory neurons (sensory input) (PNS) Integration (CNS) Motor neurons (motor output) (PNS) Effector reacts |
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Cell body |
Contains nucleus and other organelles |
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Dendrite |
Receives information |
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Axon |
Transmits information Usually only one |
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Axon hillock |
Base of axon Where action potentials are generated |
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Synapse |
Junction between axon and other cell |
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What happens at the synapse |
Neurotransmitters pass information from the presynaptic terminal to the postsynaptic terminal |
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Types of neuron shapes/sizes |
Multipolar Bipolar Unipolar |
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Multipolar neurons |
1 axon 2+ dendrites |
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Bipolar neurons |
1 axons 1 dendrite |
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Unipolar neurons |
1 axon 0 dendrites |
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Types of glial cells |
Schwann cells Oligodendrocytes Astrocytes Ependymal cells Microglial cells |
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Only glial cells in peripheral nervous system |
Schwann cells |
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Location of most glial cells |
Central nervous system |
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Schwann cells |
Make myelin |
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Oligodendrocytes |
Make myelin |
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Glial cells that make myelin |
Oligodendrocytes Schwann cells |
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Astrocytes |
Repair injury Look like stars |
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Ependymal cells |
Make cerebral spinal fluid |
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Microglial cells |
Macrophages Remove waste such as dead cells and pathogens |
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Resting membrane potential |
The difference in electrical charge across a plasma membrane of a neuron at rest |
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Resting membrane potential values in a neuron |
The inside is -60mV to -80mV more negative than the outside |
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Distribution of ions inside and outside the neuron |
K+ is highest inside the cell Na+ is highest outside the cell
Maintained by respective pumps |
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Ratio of Na+ and K+ pumped |
3 Na+ pumped out per 2 K+ pumped in |
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Opposing forces that move ions in and out of the neuron reflected by resting membrane potential |
Diffusion Electrostatic pressure |
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Diffusion |
Molecules moving from a region of high concentration to one of low concentration |
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Electrostatic pressure |
Like charges repel and opposite charges attract |
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Ion channels on membrane are |
Selectively permeable |
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Ion channels in the membrane |
More K+ channels than Na+ channels Significant output of cations K+ outflow leads to a net negative charge inside the neuron |
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What happens when the negative charge builds inside the neuron |
It begins to exert electrostatic pressure |
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What happens during electrostatic pressure |
Cell pulls K+ ions back inside |
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Goal of diffusion and electrical forces |
Equilibrium |
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Equilibrium potential |
Eion The membrane voltage at equilibrium for a particular ion |
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How to calculate equilibrium potential |
Nernst equation
Eion = 62mV (log[ion]outside/[ion]inside) |
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How membrane potential changes during the generation of a nerve impulse |
Hyperpolarization Depolarization |
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Hyperpolarization |
Neuron becomes more negative inside relative to the outside |
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When hyperpolarization occurs |
When a signal is sent
Signals do not always cause hyperpolarization |
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Depolarization |
Membrane potential moves closer to zero |
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When an action potential occurs |
When a depolarization increases the membrane voltage to threshold
No action potential unless you have a stimulus strong enough |
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Threshold of action potential (value) |
-55mV |
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All-or-none property |
Either it fires at full amplitude or not at all |