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英语翻译where A is the cross-sectional area in cm and L is the l

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英语翻译
where A is the cross-sectional area in cm and L is the length of the material in cm.Thus,
if we consider a single ion channel to be a cylinder of known length and cross-sectional
area filled with a solution of known resistivity,it is possible to estimate the resistance.This
value needs to be adjusted to include such factors as the availability of ions to actually
pass through the channel as well as the ease with which the channel passes ions.For the
purposes of this research,it will be assumed there is an adequate supply of ions available
for transport through the membrane and that the membrane itself does not hinder that
transport in any way beyond the physical constrictions used to determine the resistance.
The total resistance of the plasma membrane can then be calculated by considering the
parallel combination of all the ionic channels permeating the membrane that are open for
ion transport.Measurement of the membrane resistance can thus be used as an indicator of
how many ionic channels are open at any given time.Indeed,the first suggestion that the
fluxes of sodium and potassium ions associated with an action potential had to be
attributed to holes or channels through the membrane was deduced by measurements of
transmembrane impedance of the squid giant axon [Hodgkin and Huxley,1952].
Individual ionic channels have a resistance (when open) of 5 to 500 GW depending on the
channel type and tissue.Depending on the cell type,the location of the patch of
membrane,and the transmembrane potential,the overall membrane resistance can range
2
from 1MW to 100 GW*μm .This data was compiled using individual channel resistances
and density ranges found in [Hille,1992] for a variety of tissues and channel types.
The plasma membrane itself is an insulating layer separating two conducting solutions
(i.e.,a capacitor).The capacitance is determined by the permeability of the material (e ),
r
the area (A) and the thickness (d):
A是以厘米为单位的横截面,L是材料的长度,用cm表示.因而,
如果我们考虑一个单一的离子通道是一个圆柱体的已知长度和横截面
地区充满解决已知的电阻率,这是无法估计的阻力.这个
价值需要加以调整,以包括这些因素的可得性离子实际
通过渠道以及容易在离子通道通行证.为
本研究的目的,这将是假定有足够的离子可
通过对运输的膜和膜本身并不妨碍该
以任何方式运输以外的身体收缩来确定的阻力.
总抵抗质膜然后可以考虑计算
并行组合所有离子通道渗透膜是开放
离子转运.测量膜电阻,因此,可以作为一个指标
多少离子通道的开放在任何特定时间.事实上,第一个建议,即
通量的钠和钾离子与行动的潜力,必须
归因于孔或通道通过膜推导出测量
跨膜阻抗乌贼巨轴突[霍奇金淋巴瘤和赫胥黎,1952 ] .
单独的离子通道的阻力(打开时)的5至500万千瓦依
渠道类型和组织.根据不同的细胞类型,所在地的补丁的
膜和膜电位,但总的膜电阻可以范围
2
从1MW至100万千瓦*微米.这些数据汇编使用单个通道电阻
和密度范围在[惠勒,1992 ]为各种组织和渠道类型.
细胞膜本身就是一个绝缘层进行分隔两个解决方案
(即电容器) .电容是由透气材料( e )项,
r
面积( A )和厚度( d )项: