肾小体（英语：Renal corpuscle）、在肾脏中、是肾元中首先进行过滤工作的单位，它包含了由动脉性微血管组成的肾小球，并被囊状的鲍氏囊包围起来。经超滤作用（Ultrafitration）后，来自肾小球血球中的液体，形成肾小球滤液，由鲍氏囊收集起来，接着经由肾元的其他构造，形成尿液。肾小球的入球小动脉直径大于出球小动脉，这样的构造使肾小球的血压（静液压）可达70毫米汞柱，是全身微血管压力最大的地方。

进入肾小球的过滤物质都要先经过鲍氏囊和肾小球间的内皮囊膜（endothelial capsular membrane），内皮囊膜包含了肾小球微血管的内皮、基底膜、及鲍氏囊的脏层上皮（足细胞）。正常状况下，血液中的红血球和蛋白质无法通过内皮囊膜，但是在肾小球发炎时，红血球和蛋白质可能会通过内皮囊膜，混合到尿液中。

In the kidney, a renal corpuscle is the initial blood-filtering component of a nephron. It consists of two structures: a glomerulus and a Bowman's capsule.

The glomerulus is a small tuft of capillaries containing two cell types. Endothelial cells, which have large fenestrae, are not covered by diaphragms. Mesangial cells are modified smooth muscle cells that lie between the capillaries. They regulate blood flow by their contractile activity and secrete extracellular matrix, prostaglandins, and cytokines. Mesangial cells also have phagocytic activity, removing proteins and other molecules trapped in the glomerular basement membrane or filtration barrier.