nephronis also known as the unit of kidney

All about kidney and nephron

1. Anatomy and physiology of nephron

2. INTRODUCTION " Nephron is the basic structural & functional unit of kidney which helps in formation of urine. The word nephron is derived from the Greek word nephros , meaning kidney. There are about millions of nephrons in each human kidney.

3. ANATOMY OF NEPHRON It is a long tube-like structure, its length varies from 35-55 mm long. The structure of nephron comprises two major portions: A. Renal Corpuscle B. Renal Tubule At one end, the tube is closed, folded and expanded, into a cuplike structure called the Bowman's capsule or renal corpuscular capsule, which has cluster of blood vessels called the glomerulus . Renal corpuscle=Bowman's capsule+Glomerulus

4. GLOMERULUS Anatomosing capillaries present in kidney invested by double layered of epithelial cells making bowman’s capsule and capillaries are embedded with in mesangium . Whole glomerulus is functionally filteration unit of nephron .

5. Glomerular capillary tuft is surrounded by or invested by group of epithelial cells which is double layered cells and these cells have some foot processes called podocytes . Double layered epithelial cells make capsule – bowman’s capsule B/w capillaries there is specialise cells present – mesangial cells. B/w endothelial cells of capillary membrane and visceral epithelial membrane of bowman’s capsule present- glomerular basement membrane

6. endothelial cells which line the glomerular capillaries and these endothelial cells have thousand of holes with in the cells structures these cells are called fenestrated i.e.these capillaries are called fenestrated capillaries(enhance the filteration ). Size of holes - 70-100 nm. under microscope, glomerular basement membrane centre area very dense lamina densa , outer lamina rara interna and lamina rara externa . Tips of foot process of epithelial cells attach to glomerular basement membrane. Visceral epithelial cells are interdigitate and between the interdigitation area called filteration slit .(size- 20-30nm) Filteration slit - - having filteration diaphragm.This filleration diaphragm is made from special protein called nephrin .

7. Filtration barrier : Fenestrated capillary endothelium Glomerular basement membrane filtration slit or slit diaphragm

8. In some patients there is formation of antibodies against non collagenous structure and these antibodies damage GBM and leads to hematuria and proteinuria – anti gbm antibodies or anti gbm glomerulonephritis . These antigens present in alveolar basement membrane and these antibodies react against gbm but also against alveolar basement membrane leads to hemoptysis and will produce hematuria and hemoptysis – called good pasture syndome

9. Type 4 collagen and laminin are the main component of GBM. The 3 layers of glomerular capillary membrane acts as filtration barrier and ultrafiltrate is formed. GBM has negative charge, hence negatively charged bodies are not filtered. For a give molecular radius, the filtration is positive molecules>neutral>negative .

10. PODOCYTES AND THEIR ROLE Podocytes (visceral epithelial cells) are the largest cells in the glomerulus . Mature podocytes are terminally differentiated They have a prominent cell body containing nuclei, endoplasmic reticulum, Golgi apparatus, and an endocytic-lysosomal system. The gap between adjacent foot processes is bridged by a thin structure called the filtration slit diaphragm.

11. THANK YOU