Key Difference – Rodvs锥细胞
感光体是细胞在眼睛的视网膜中对光的反应。这些细胞的区别特征是存在紧密堆积的膜,该膜包含被称为称为的照片rhodopsinor related molecules. The photopigments have a similar structure. All photopigments consist of a蛋白质叫OPSIN和一个被称为一个的小分子发色团。发色团通过涉及其构型变化的机制吸收光的一部分。这些光感受器的膜中的紧密堆积非常有价值,以达到高光谱密度。这使得到达光感受器的大部分光光子被吸收。在vertebrates,,,,the retina consists of two photoreceptors (rod and cone cells) which are bearing photopigment at their outer region. This particular region is composed of a large number of pancake-like disks. In rod cells, the disks are closed, but in the cone cells, the disks are partially open to the surrounding fluids. In invertebrates, the photoreceptors structure is very different. The photopigment was born in a regularly arranged structure called as微壁画,finger-like projections with about diameter of 0.1µm. This photoreceptor structure in invertebrates is known as横把。与脊椎动物的磁盘相比,横纹型中的光鲜齐成本较少。这关键区别between rod and cone cells is that the杆细胞负责低光水平(Scotopic Vision)的视力,而圆锥细胞在较高的光水平(光波视觉)处活跃。
CONTENTS
1。概述和关键差异
2。What are Rod Cells
3。什么是锥细胞
4。杆和锥细胞之间的相似性
5。并排比较 - 表格形式的杆vs锥细胞
6。概括
什么是杆细胞?
棒细胞是眼睛中的感光体,它可以在低强度的光下起作用,而不是眼睛的另一个被称为“锥细胞”的光感受器。杆通常集中在视网膜的外边缘,并负责外围视力。据估计,在人类视网膜中发现了大约9000万个棒细胞。发现杆细胞比锥细胞更敏感,几乎完全负责夜视。杆细胞在色觉中只有很少的部分。这就是为什么颜色在黑暗中不太明显的原因。杆细胞比结构中的锥细胞更长,更瘦。在连接到视网膜色素的细胞的末端可以看到含有磁盘的磁盘上皮依次固定在巩膜上。杆细胞(1亿)比锥细胞(700万)更常见。
杆有三个部分;外部段,内部段和突触段。突触段与另一个神经元(双极细胞或水平细胞)形成突触。内部和外部段通过纤毛连接。可以在内部段中观察到像细胞核之类的细胞器。外部段包含光吸收材料。
在vertebrates, the activation of the photoreceptor cell is known as hyperpolarization of the cell, which leads to the rod cell for not sending itsneurotransmitter,这导致双极细胞在双极神经节在其神经递质的释放中释放synapse激发突触。所以,这是一个级联反应n that takes place in that. Activation of a single unit of photosensitive pigment can give rise to the larger reaction in the cell. Thus, the rod cells can trigger a larger response to a smaller amount of light.Vitamin A缺乏会导致杆细胞所需的少量色素。这被诊断为夜盲症。
什么是锥细胞?
锥细胞是人类视网膜中发现的感光体之一,在明亮的光线状态下起作用,并允许色觉。彩色视觉基于大脑在接收三种类型的锥体(l-long,s-short和m-介质)的神经信号时构造颜色的能力,每种锥体对光范围的视觉光谱都敏感。这取决于三种不同锥细胞中存在的三种光蛋白。一些脊椎动物可能具有四种类型的锥细胞,从而使它们具有四型视觉。锥体系统的部分或完全丢失会导致色盲。锥细胞比杆细胞短。但是它们更宽且锥形。它们的长度为40-50µm,直径为0.5µm-4µm。它们大部分被挤在眼中的中央(Fovea)。与眼睛中的其他锥体(M和L)相比,S锥被随机放置,并且频率较小。
锥体还由三个段(外部段,内部段和突触段)组成。内部细分市场包含nucleusand few线粒体。突触段用双极细胞形成突触。内部和外部段通过纤毛连接。癌性视网膜细胞瘤是由于视网膜锥细胞中称为RB1的一个基因的缺陷。这种情况是在幼儿时期出现的。该特定基因控制信号转导和正常的细胞周期进程。
What are the Similarities Between Rod and Cone Cells?
- 两者都在视网膜的视网膜中发现。
- Both are photoreceptors.
- Both contain visual pigments.
- Both are types of secondary exteroceptors.
杆和锥细胞有什么区别?
杆细胞与锥细胞 |
|
杆细胞是负责低光水平视力的感光体。 | Cone cells are the photoreceptors responsible for vision at the high-intensity light levels. |
照相数量 | |
杆细胞具有更多的光鲜色。 | 锥细胞具有较少的光成色。 |
Amplification | |
杆细胞显示出更多的扩增。 | Cone cells show less amplification. |
Directionally Selectiveness | |
杆细胞在方向上没有显示性能。 | Cone cells show directionally selectiveness. |
Sensitivity | |
Rod cells have a high sensitivity. | Cone cells have a low sensitivity. |
Convergent Retinal Pathway | |
Rod cells do have a high convergent retinal pathway. | 锥细胞确实具有较少收敛的视网膜途径。 |
回复 | |
杆细胞显示缓慢的响应。 | 锥细胞显示快速响应。 |
Acuity | |
Rod cells show low acuity. | Cone cells show high acuity. |
色素类型 | |
Rod cells have only one type of pigments | Cone cells have three types of pigments. |
Visual Pigments | |
这visual pigment in the rod cells is Rhodopsin. | 锥细胞中的视觉颜料是碘播。 |
摘要 - 杆vs锥细胞
这photoreceptors (rod and cone cells) are cells in the retina of the eye which respond to the light. The distinguishing feature of these cells, is the presence of tightly packed membrane that contains the photopigment; rhodopsin or related molecules. The tight packing in the membranes of these photoreceptors is highly valuable in order to achieve a high amount of photopigment density and number. This allows a large portion of light photons that reach the photoreceptors to be absorbed. In vertebrates, the retina consists of two photoreceptors (rod and cone cells) which bear photopigment constituted in the outer region. This particular region is composed of a large number of pancake-like disks. The rod cells can function at low-intensity light (Scotopic)。另一方面,锥细胞在高强度光(光平)下具有活性。这是杆和锥细胞之间的差异。
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Reference:
1。”Cone cell.” Wikipedia, Wikimedia Foundation, 22 Oct. 2017.Available here
图片提供:
1。’1414 Rods and Cones’By OpenStax College – Anatomy & Physiology,连接网站。2013年6月19日。(CC由3.0)通过下议院维基梅迪亚
2.’Cone Cell en’撰写的IvoKruusamägi - 自己的作品,(CC BY-SA 3.0)通过下议院维基梅迪亚
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