action potential

简明释义

动诅位

英英释义

例句

1.When a stimulus reaches a certain threshold, it triggers an action potential 动作电位 that travels along the axon.

当刺激达到一定阈值时，会触发沿轴突传播的动作电位。

2.The generation of an action potential 动作电位 in neurons is crucial for transmitting signals in the nervous system.

神经元中动作电位的产生对于在神经系统中传递信号至关重要。

3.In muscle cells, the initiation of an action potential 动作电位 leads to contraction.

在肌肉细胞中，动作电位的启动会导致收缩。

4.Researchers study the action potential 动作电位 to understand how information is processed in the brain.

研究人员研究动作电位以了解大脑如何处理信息。

5.The speed of an action potential 动作电位 can be influenced by the myelination of the neuron.

神经元的髓鞘化会影响动作电位的速度。

作文

The term action potential refers to a rapid and temporary change in the electrical membrane potential of a cell, particularly in neurons and muscle cells. This phenomenon is crucial for the transmission of signals within the nervous system. When a neuron is stimulated by an external signal, such as a neurotransmitter or a sensory input, it undergoes a series of changes that lead to the generation of an action potential. Initially, the resting membrane potential, which is typically around -70 millivolts, becomes less negative due to the influx of sodium ions (Na+) through voltage-gated sodium channels. This depolarization phase is essential because it allows the neuron to reach a threshold level, usually around -55 millivolts.Once this threshold is reached, a full-blown action potential is triggered, resulting in a rapid spike in membrane potential that can rise to +30 millivolts. This spike is primarily due to the opening of additional sodium channels, leading to a further influx of Na+ ions. Following this peak, the process of repolarization begins, where potassium ions (K+) exit the cell through voltage-gated potassium channels, causing the membrane potential to become more negative again. This phase is crucial for restoring the resting state of the neuron.After the repolarization, there is often a brief period known as the refractory period, during which the neuron cannot fire another action potential immediately. This ensures that signals travel in one direction along the axon and also sets a limit on the frequency of firing. The entire process of generating and propagating an action potential is fundamental to how neurons communicate with each other and with muscles, enabling everything from reflexes to complex thoughts.Understanding the mechanics of action potentials is vital not only for neuroscience but also for medical science, as abnormalities in this process can lead to various neurological disorders. For instance, conditions such as epilepsy can arise from irregularities in the generation or propagation of action potentials, leading to uncontrolled neuronal firing. Similarly, heart arrhythmias can occur when cardiac cells fail to generate proper action potentials, disrupting the coordinated contractions necessary for effective blood circulation.In conclusion, the concept of action potential is foundational to our understanding of cellular communication in biological systems. It illustrates how electrical signals are generated and transmitted, forming the basis for complex behaviors and physiological functions. As research continues to explore the intricacies of action potentials, we gain deeper insights into the workings of the brain and body, paving the way for advancements in medical treatment and technology. By grasping the significance of action potentials, we can appreciate the elegance of life at a cellular level and the intricate dance of ions that underpins our very existence.

术语动作电位指的是细胞电膜电位的快速和暂时变化，特别是在神经元和肌肉细胞中。这一现象对于神经系统内信号的传递至关重要。当神经元受到外部信号的刺激，例如神经递质或感觉输入时，它会经历一系列变化，导致生成动作电位。最初，静息膜电位通常约为-70毫伏，由于钠离子(Na+)通过电压门控钠通道的流入，膜电位变得不那么负。这一去极化阶段是必不可少的，因为它使神经元达到阈值水平，通常约为-55毫伏。一旦达到这个阈值，就会触发一个完整的动作电位，导致膜电位迅速上升到+30毫伏。这一峰值主要是由于额外的钠通道的开启，导致Na+离子的进一步流入。在这一峰值之后，复极化过程开始，钾离子(K+)通过电压门控钾通道退出细胞，使膜电位再次变得更负。这个阶段对于恢复神经元的静息状态至关重要。在复极化之后，通常会有一个短暂的时期称为不应期，在此期间神经元无法立即发出另一个动作电位。这确保了信号沿轴突单向传播，并且限制了发射的频率。生成和传播动作电位的整个过程是神经元之间及与肌肉之间沟通的基础，使从反射到复杂思维的所有过程成为可能。理解动作电位的机制不仅对于神经科学至关重要，也对医学科学至关重要，因为这一过程中的异常可能导致各种神经系统疾病。例如，癫痫等状况可能源于动作电位的生成或传播不规则，导致神经元的失控放电。同样，心律失常可能发生在心脏细胞未能生成适当的动作电位时，破坏有效血液循环所需的协调收缩。总之，动作电位的概念是我们理解生物系统中细胞通信的基础。它展示了如何产生和传递电信号，形成复杂行为和生理功能的基础。随着研究继续探索动作电位的复杂性，我们对大脑和身体的运作有了更深入的了解，为医疗治疗和技术的进步铺平了道路。通过掌握动作电位的重要性，我们可以欣赏生命在细胞层面的优雅以及支撑我们存在的离子之间复杂的舞蹈。