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27 Cards in this Set
- Front
- Back
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2 main classes of cells in Nervous System
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1. Neurons 2. Glial Cells |
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Neurons |
-over 1 billion in the body |
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Neurons: shared components w other cells |
mitochondria endoplasmic reticulum Golgi apparatus Cytoplasm Nucleus |
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Neurons: components unique from other cells |
Dendrites Axons |
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Dendrites |
info can be excitatory (increasing stimulation of the neuron) or inhibitory (decreasing activity of the neuron) |
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Action potentials
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-explosion of electrical energy triggered by change in voltage across membrane -helped by the nodes of Ranvier which help move signal down the axon (saltatory conduction) |
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Axons |
-messages travel down the axon to its end (axon terminal) where transmission occurs at synapse -many wrapped in myelin |
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Synapse |
-a space between cells across which electrical or chemical signals must pass |
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Neurotransmitters |
chemical or electrical messengers that leave the presynaptic area(axon), cross the synaptic junction, and are received in the postsynaptic aea (dendrite) |
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-protective sheath that provides a boost to the speed of the neuronal signal -produced by Schwann cells in PNS and Ogliodendrocytes in the CNS |
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Nodes of Ranvier |
unmyelinated gaps in myelin sheath |
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Electrical potential |
-the difference in the voltage inside the neuron vs outside -No active signaling = resting state |
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Resting State
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outside cell = positive -bc neg and pos charges exist on opposite sides, cell is polarized |
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Sodium-Potassium Pumps: definition |
-a type of ion pump that helps to actively maintain the polarized state of the neuronal membrane
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S-P pumps in action |
-resting -neuron receives signal -channels open allowing sodium ions (+) which depolarize membrane -once cell reaches threshold, action potentials fire -after AP fires, channels open allowing influx of potassium ions (-), repolarizing the cell -back to resting |
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Synaptic transmission
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the transfer of a signal form the axon terminal to the next cell |
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Types of Neurotransmitters |
Biogenic Amines (Catecholamides)(dopamine, norepinephrine, and epinephrine) Acetylcholine Neuropeptides |
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What happens to remaining transmitters after release to prevent further signal activity? |
2. enzymatic breakdown in cleft 3. diffusion |
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Electrical vs Chemical Synapses
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electrical impulses are faster as they are not separated by the synaptic junction
-'gap junctions' where neuronal membranes touch |
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Glial cells |
aka neuroglial -provide support in the nervous system by aiding speed of transmission, helping form blood brain barrier, forming myelin, providing nutrients, and destroying pathogens |
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Types of Glial Cells |
1. Astrocytes 2 Microglial 3. Ogliodendrocytes |
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Astrocytes |
star shaped part of BBB (blood brain barrier)- allows CO2 Oxygen and hormones IN, keeps bacteria OUT moderates neural activity |
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Microglia |
aka phagocytes
-helps clean damaged tissue, destroys pathogens, and promotes repair in CNS |
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Ogliodendrocytes |
creates myelin sheaths around the axons of neurons in the CNS (Schwann cells perform this function in PNS) |
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Interconnectivity |
typical neuron has 1 K- 5 K synapses |
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Corticocortical connections |
connections between 2 cortical regions |
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neural circuits |
groups of interconnected neurons |
