There are some muscle fibers here that show atrophy. The number of cells is the same as before the atrophy occurred, but the size of some fibers is reduced. This is a response to injury by "downsizing" to conserve the cell. In this case, innervation of the small fibers in the center was lost. This is a trichrome stain.

三色染色法示：萎缩的肌纤维
虽然细胞数量与萎缩前相同，但肌纤维缩小了。这是一种对损伤的适应性反应，通过萎缩使其存活。本例萎缩的肌纤维没有神经的支配(去神经性萎缩)。

The testis at the right has undergone atrophy and is much smaller than the normal testis at the left.

图示：萎缩的睾丸

右侧的萎缩睾丸比左侧的正常睾丸小得多。

This is cerebral atrophy in a patient with Alzheimer's disease. The gyri are narrowed and the sulci widened toward to frontal pole.

图示：阿尔茨海默症时脑萎缩。

脑回变窄，通向额极的脑沟变宽。

Here is the centrilobular portion of liver next to a central vein. The cells have reduced in size or been lost from hypoxia. The pale brown-yellow pigment is lipochrome that has accumulated as the atrophic and dying cells undergo autophagocytosis.

可见肝中央静脉的肝小叶中央区。由于缺氧细胞已萎缩或消失。萎缩的和将坏死的细胞自溶使得棕黄色的脂色素斑块堆积。

This is cardiac hypertrophy involving the left ventricle. The number of myocardial fibers does not increase, but their size can increase in response to an increased workload, leading to the marked thickening of the left ventricle in this patient with systemic hypertension.

图示心肌肥大（左心室）

心肌纤维的数量虽然没有增加，但是心肌纤维为了适应心脏负荷的增加而体积增大（肥大）。此为高血压病人肥大的心脏，左心室明显增厚。

The prominent folds of endometrium in this uterus opened to reveal the endometrial cavity are an example of hyperplasia. Cells forming both the endometrial glands and the stroma have increased in number. As a result, the size of the endometrium has increased. This increase is physiologic with a normal menstrual cycle.

在这个纵向剖开的子宫腔面可以看到明显增生的子宫内膜。子宫腺细胞和基质数量增多。这种增生是随月经周期而发生的生理性变化。

This is an example of prostatic hyperplasia. The normal prostate is about 3 to 4 cm in diameter. The number of prostatic glands, as well as the stroma, has increased. The pattern of increase here is not uniform, but nodular. This increase is in response to hormonal manipulation, but in this case is not a normal physiologic process.

图示：前列腺增生。正常的前列腺直径有3-4cm，前列腺细胞的数量和基质细胞一样都增加了。但由于这种增生是不均衡的，而呈现为小结节。这种改变虽然是受性激素调节的，但不是生理性增生。

Here is one of the nodules of hyperplastic prostate. The cells making up the glands are normal in appearance, there are just too many of them.

图示：增生前列腺结节

由许多细胞构成的腺体看起来是正常的，但数量明显增加了。

Metaplasia of laryngeal respiratory epithelium has occurred here in a smoker. The chronic irritation has led to an exchanging of one type of epithelium (the normal respiratory epithelium at the right) for another (the more resilient squamous epithelium at the left). Metaplasia is not a normal physiologic process and may be the first step toward neoplasia.

图示：嗜烟者喉部呼吸道上皮化生

长期的慢性刺激使一种上皮（右侧的是正常的呼吸道粘膜上皮）转变为另一种上皮（左侧的是鳞状上皮）。化生不是生理过程，而可能是肿瘤形成的先兆。

Metaplasia of esophageal squamous mucosa has occurred here, with gastric type columnar mucosa at the left.

食管粘膜的鳞状上皮已经发生了化生，左侧酷似胃粘膜柱状上皮。