Quick Facts
A podocyte is a modified epithelial cell of the visceral layer of the glomerular capsule in the renal glomerulus; it has a small perikaryon and several primary and secondary foot-like radiating processes (pedicels) that interdigitate with those of other podocytes and embrace the walls of glomerular capillaries (Dorland, 2011).
Related parts of the anatomy
Structure and/or Key Feature(s)
The visceral layer of the glomerular (Bowman’s) capsule contains specialized visceral epithelial cells called podocytes. Each podocyte extends primary cytoplasmic processes around glomerular capillaries. Each primary process extends numerous secondary processes, called foot processes, which interdigitate with those of a neighboring podocyte. Elongated spaces (around 40 nm wide), call filtration slits, extend between the interdigitating foot processes . They are covered by an ultra-thin filtration slit diaphragm (Ovalle, Nahirney and Netter, 2013; Ross and Pawlina, 2006). The subpodocyte space is found between the podocyte cell body on one side and the foot processes and filtration slit diaphragms on the other.
The filtration slit diaphragm is a complex protein structure. A transmembrane protein, “nephrin,” is the key structural and functional component. Nephrin molecules emerge from foot processes and attach to the filtration slit forming a central density with pores on both sides. The filtration slit diaphragm contains other adhesion molecules, such as Neph-1 and -2, P-cadherin, and FAT1 and FAT2, and is anchored to numerous actin filaments in the foot processes of podocytes (Ross and Pawlina, 2006).
Anatomical Relations
The visceral layer of the glomerular capsule contains specialized epithelial cells called podocytes that are intimately associated with glomerular capillaries.
Function
Podocytes or visceral epithelial cells are a major component of the filtration apparatus.
List of Clinical Correlates
Regulation and maintenance of the actin cytoskeleton of podocytes are critical for the functional integrity of the filtration slit diaphragm. Mutations in the nephrin gene (NPHS1) are associated with congenital nephrotic syndrome, a disease characterized by massive proteinuria and edema (Ross and Pawlina, 2006).
References
Dorland, W. (2011) Dorland's Illustrated Medical Dictionary. 32nd edn. Philadelphia, USA: Elsevier Saunders.
Ovalle, W. K., Nahirney, P. C. and Netter, F. H. (2013) Netter's Essential Histology. ClinicalKey 2012: Elsevier Saunders.
Ross, M. H. and Pawlina, W. (2006) Histology: A text and atlas. Lippincott Williams & Wilkins.
