第2章 上皮组织
Chapter 2 Epithelial tissue

No.6 单层扁平上皮 Simple squamous epithelium

大网膜铺片，狗，银染法 Spread preparation of omentum，dog，silver staining

取动物大网膜经硝酸银浸染，剪成小块平铺于载玻片上而制成。用其观察单层扁平上皮的正面形态结构。

选择大网膜铺成单层，且背景较清楚的部分观察。

上皮细胞呈不规则形或多边形，相邻细胞之间有棕黑色的硝酸银颗粒沉积。

细胞之间的硝酸银颗粒较大且多，故着色深；胞质内的硝酸银颗粒细小而分散。细胞核呈椭圆形，着蓝色（苏木素复染）。

In this preparation，the mesothelial lining of the peritoneal cavity has been stripped from the underlying connective tissues and spread onto a slide thus permitting a surface view of simple squamous epithelium.

Low and high power：Simple squamous epithelium（the mesothelium）is observed with surface view. The intercellular substance has been stained with silver outlining the closely interdigitating cell boundaries. The nuclei of the cells are centrally or eccentrically located, which have been stained with the dye，hematoxylin.

No.46 单层扁平上皮 Simple squamous epithelium

小肠，狗 Small intestine，dog，H&E

〔4倍物镜〕呈指状突起的一面为小肠黏膜，与其相对的另一面是小肠的腹腔面，被覆单层扁平上皮。

〔10倍物镜〕在切片的边缘有一条弯曲，且着浅红色的细带，为单层扁平上皮的侧面观，其内断续的紫蓝色的点状结构，此即单层扁平上皮细胞核。选细胞核较多、排列较整齐的部位，换40倍物镜进一步观察。

〔40倍物镜〕单层扁平上皮的侧面观，其细胞核呈扁椭圆形或卵圆形，胞核的长轴与上皮的表面平行。因上皮细胞呈薄片状，故仅见胞核周围少量的嗜酸性胞质。

Naked eye：The wave-like violet band is the intestinal mucosa. The opposite margin is the outer surface of the small intestine covered by the simple squamous epithelium，called mesothelium.

Low and high power：The mesothelial lining cells are so flattened that they can only be recognized by their nuclei which are basophilic and bulge into the lumen. The supporting basement membrane is very thin and can not be seen in this micrograph. In the underlying connective tissue，another type of simple squamous epithelium，called endothelium，can be found to line some small blood vessels.

No.46 单层柱状上皮 Simple columnar epithelium

小肠，狗 Small intestine，dog，H&E

〔4倍物镜〕这是空肠的纵切面组织切片，平坦的一边是空肠的外表面，即腹腔面；有大小指状突起的一边是空肠的内表面，即肠腔面，其表面被覆单层柱状上皮。

〔10倍物镜〕指状突起表面所被覆的组织是单层柱状上皮，细胞核呈长椭圆形或杆状，众多的细胞核紧密排列成一层。有些部位的上皮细胞核聚集成堆或排成多层，此因该处众多的上皮细胞被斜切所致。少数细胞核上部的胞质呈圆形或椭圆形空泡状，该细胞为杯状细胞。选择细胞核排列成单层的部位，换40倍物镜观察。

〔40倍物镜〕小肠单层柱状上皮的游离面有一条红色的带状结构，称纹状缘。柱状的上皮细胞紧密排列成一层，细胞间的界限有的不清楚。但是，可根据细胞核呈长椭圆形或长杆状，并排列为一排，即可推断该上皮是由单层的柱状细胞组成（一般而言，细胞核的形态是与该细胞的形状相对应的）。细胞核的长轴与细胞的长轴一致，偏居细胞的基底部。柱状的上皮细胞间可见杯状细胞，其外形似高脚酒杯，细胞核上部的胞质内，有个圆形或椭圆形的空泡区（此因该处胞质内的黏原颗粒在制片过程中被溶解，致使颗粒所在区着色很浅）；细胞游离面的纹状缘中断；细胞核常呈三角形或杆状，着深蓝色，位于细胞基底部。

Naked eye：The violet band is the intestinal mucosa.

Low power：Find out finger-like projections（villi）on the mucosa side. The surface of villi is covered by simple columnar epithelium, in which tightly compacted nuclei can be seen in one layer.

High power：Two kinds of cells are present in this epithelium. Columnar cell has an oval nucleus with its long axis paralleling to the long axis of the cell. The luminal plasma membranes of columnar cells are often arranged into numerous，minute，finger-like projections called microvilli which are too small to be resolved individually. But the microvilli collectively give the appearance of a striated border at the luminal surface. Between the columnar cells，goblet cell is irregularly distributed and shows a vacuole feature with a dark nucleus below the vacuolar cytoplasm.

No.54 假复层纤毛柱状上皮 Pseudostratified ciliated columnar epithelium

气管，人 Trachea，human，H&E

〔4倍物镜〕气管横切面的组织切片，呈半环形或环形，凹面（气管腔面）被覆假复层纤毛柱状上皮。

〔10倍物镜〕沿气管腔面观察，假复层纤毛柱状上皮的细胞核密集排列成数层，染成蓝色。选择层次结构较清晰的部位，换40倍物镜观察。

〔40倍物镜〕上皮细胞界限不清，游离面有呈簇或成排的浅红色细丝，即纤毛。纤毛所在的细胞，为纤毛细胞，呈柱状，该细胞上半部呈柱状，下半部纤细；细胞核呈椭圆形，位于多层上皮细胞核的浅层。纤毛细胞间常有杯状细胞。深层的细胞核多呈圆形，胞质甚少且不清楚，此即锥体形细胞。其他的细胞多数是梭形细胞，细胞核圆形，位于成层排列的胞核的中间层。常见浸入上皮内的小淋巴细胞，其核小而圆，着色很深。上皮基部的基膜，着淡红色，呈细线状，有时不明显。

Naked eye：The inner surface is purple and lined with epithelium.

Low power：The term pseudostratified is derived from the appearance of this epithelium in section which conveys the erroneous impression that there is more than one layer of cells. This，however，is a true simple epithelium since all the cells rest on the basement membrane，although not all the cells extend to the luminal surface. The nuclei of these cells are disposed at different levels，thus creating the illusion of cellular stratification.

High power：There are approximately 3 layers of nuclei showing a stratified appearance. The upper nuclei belong to columnar cells whose free surface has a lot of cilia. The nuclei of fusiform cells are in the middle. The nuclei at the bottom just above the obvious basal membrane are nuclei of pyramidal cells. Goblet cells are also present. The columnar cells and goblet cells reach the surface.

No.43 未角化复层扁平上皮 Nonkeratinized stratified squamous epithelium

食管，人 Esophagus，human，H&E

〔4倍物镜〕为横切的食管组织切片，管腔不规则，近腔面紫红色的弯曲环带为未角化复层扁平上皮。

〔10倍物镜〕食管腔面的未角化复层扁平上皮，细胞层次多，各处厚薄不一。基底层的细胞胞质呈强嗜碱性，趋向上皮浅表层，细胞质呈嗜酸性。上皮的基部起伏不平，在其深部，染浅红色的结缔组织呈指状或乳头状突入上皮。

〔40倍物镜〕浅层的上皮细胞呈扁平状或鳞片状，胞质着淡红色，胞核小，呈扁圆形，与上皮表面平行。中间层的上皮细胞呈多边形，细胞界限较清楚。丰富的胞质呈嗜酸性，胞核呈圆形或卵圆形。基底层的上皮细胞为矮柱状，胞核呈椭圆形；细胞质少，强嗜碱性。上皮的基部，有薄层的嗜酸性基膜，不明显。

Naked eye：The purple line placed on the lumen side of this organ is epithelium.

Low power：The epithelium is composed of many layers of cells which undergo morphological transition from the cuboidal basal layer to the extremely flattened surface layers. The junction between epithelium and underlying connective tissue is usually irregular. The projection of connective tissue into the epithelium is called dermal papillae.

High power: Note the highly cellular basal layer and the transition from the large polygonal cells of the intermediate layers to the superficial squamous cells.

No.60 变移上皮 Transitional epithelium

膀胱，空虚状态，狗 Bladder，non-distended state，dog，H&E

〔4倍物镜〕此为空虚时膀胱的切片，膀胱的外表面被覆单层扁平上皮，内表面即腔面被覆变移上皮。

〔10倍物镜〕变移上皮较厚，上皮细胞层次多，表层的细胞体积大，上皮基底面与结缔组织交界处较平坦。

〔40倍物镜〕自上皮的表层向基底层方向顺次观察。表层的细胞体积大，呈立方形或长方形；细胞核呈圆形或椭圆形，有的细胞含两个细胞核；细胞质丰富，嗜酸性，着色较红。中间层的细胞呈倒梨形，细胞核呈圆形。基底层的细胞核呈卵圆形或圆形。变移上皮与结缔组织之间有基膜。

Naked eye: The purple line placed on one side is transitional epithelium. The other side is covered by simple squamous epithelium.

Low Power：Several layers of cells are situated on the basement membrane.

High Power：The shape and size of the basal and intermediate cells vary considerably depending on the degree of distension，but the cells of the surface layer usually retain several characteristic features. In this “relaxed” state of the epithelium，basal and intemediate cells have a cuboidal or columnar shape. The surface cells are large and pale-stained and present a scalloped suface outline. The nuclei of the surface cells are large，round，sometimes binucleated, and often exhibit prominent nucleoli.