Introduccion la neurotrasmicion

Introduction to Neurons, Synapses, Action Potentials, and Neurotransmission
| Author: Robert Stufflebeam<BR< td> |

Overview: |

MODULE DESCRIPTION:
This module is an introduction to the structure and function of neurons, how they generate action potentials, and how they "communicate" with other neurons (neurotransmission) via synapses. This module includes flash animationsillustrating the difference between electric synapses and chemical synapses, conduction, electrical neurotransmission, and "classic" chemical neurotransmission.
MODULE COMPONENTS:
CURRICULUM
* Neurons, Synapses, Action Potentials, and Neurotransmission
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* An introduction to the structure and function of neurons, as well as how neurons communicate both electrically andchemically.
FLASH ANIMATIONS
A number of people have requested that each animation open in a blank window rather than be embedded within the text. The links below will do just that.
* The Action Potential
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* An animation illustrating how an action potential is generated.
* Synapses
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* An animation illustrating the difference betweenelectrical and chemical synapses.
* Electrical Neurotransmission
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* An animation illustrating intercellular communication (or synaptic transmission) between two neurons via gap junctions.
* "Classic" Chemical Neurotransmission
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* An animation illustrating intercellular communication (or synaptic transmission) between two neurons atchemical synapses.
ADDITIONAL FLASH RESOURCES
* Neurotransmission: Summary
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* An animation illustrating the difference between chemical neurotransmission and electrical neurotransmission.
* Long-Term Potentiation (LTP)
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* Long-Term Potentiation (LTP) is the long-lasting enhancement in communication between two neurons that results fromstimulating them simultaneously or in quick succession. This flash animation illustrates how the release of the neurotransmitter glutamate causes LTP in AMPA channels.
* Neural Synchrony
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* Neural synchrony is the simultaneous / synchronous oscillations of membrane potentials in a network of neurons connected with electrical synapses (gap junctions). It is considered by sometheorists to be the neural correlate of consciousness.

Organizing the Embryo: The Central Nervous System
In the embryonic development of a zygote, gradients of mRNAs and proteins, deposited in the egg by the mother as she formed it, give rise to cells of diverse fates despite their identical genomes.
For a discussion of the evidence that leads to this important conclusion, examine EmbryonicDevelopment: Getting Started. |
But is the embryo fully patterned in the fertilized egg? It is difficult to imagine that the relatively simple gradients in the egg could account for all the complex migration and differentiation of cells during embryonic development. And, in fact, the answer is no. However, once these gradients have sent certain cells along a particular path of gene expression,the stage is set for those cells to begin influencing nearby cells to become increasingly diversified.
In other words,
* cell-intrinsic signals (established between a nucleus and the particular cytoplasmic environment that cleavage has placed it in) lay the foundation for
* cell-cell interactions to further guide the cells of the embryo to assume their proper position in the embryoand to differentiate into their final specialized form and function.
Cell-cell interactions could — and probably do — occur in several ways:
* diffusion of a signaling molecule out of one cell and into other cells in the vicinity;
* diffusion of a signaling molecule from one cell into an adjacent cell that then secretes the same molecule to diffuse to the next cell and so on (a...