Kidney (SFLT)

Kidney - hematoxylin-eosin stained
Kidney. The single-layered flat epithelium forms the parietal sheet of Bowman's capsule. The nuclei of the epithelial cells are sheathed, the cytoplasm is hardly visible. Inside Bowman's capsule is the glomerulus - a club of blood capillaries - covered by the visceral leaf of Bowman's capsule. Around the renal corpuscle (glomerulus + Bowman's pouch) we see proximal and distal tubules.

Kidney cortex - hematoxylin-eosin stained I


You can see the renal corpuscles, proximal and distal tubules.

Kidney cortex - hematoxylin-eosin stained II


In addition to the renal corpuscle (Bowman's poudre) there are proximal tubules (eosinophilic - pink) with fewer nuclei and obscured lumina. These cells are involved in reverse resorption (they have a brush border on the apical surface at the base of the mitochondria and cytoplasmic folds with Na/K ATPase). Distal tubules are smaller and have a free lumen. They resorb only water and ions, so they have only a baso-lateral labyrinth. In the distal duct near the glomerulus, cells are specialized to detect urine composition (macula densa). They are taller with oval nuclei.

Kidney marrow - hematoxylin-eosin stained


In the marrow we see collecting ducts (higher light epithelium) and thin segments of the Henle's villi (flat epithelium).

Kidney
View of the arrangement of the cortex of the kidney. The renal corpuscles are superimposed (gradual development of new generations of nephrons). The striae medullares (collecting ducts that connect to the nephrons) run into the cortex.