Glomerular endothelial cells are perforated by thousands of small 'cracks' known as "fenestrae". These 'cracks' allow water and small solutes to pass through, but not proteins and cells.
Blood is fed to the glomerulus through the afferentarteriole, and empties into the efferentarteriole. The difference in pressure in the arterioles results in the process of ultrafiltration where fluids and soluble materials in the blood are forced out of the capillaries and into the Bowman's capsule.
Fluids collected in the Bowman's capsule is known as glomerular filtrate, which eventually becomes urine after further processing along the nephron.
Since the glomerularcapillary pressure (Pgc) i.e., filtration pressure is one important determinant of the amount of fluid that filters across the glomerular membrane into the proximal tubules, the phenomenon of renal autoregulation also serves to regulate the glomerularfiltration rate by supporting the Pgc.
The “effective pore size” of the glomerular filter is a complex concept and depends on a range of factors which include the size, shape and charge of the filtered particles, as well as the characteristics of the glomerulus itself.
The glomerularfiltrate is defined as an ultrafiltrate of plasma, that is, a protein-free filtrate of plasma.
The process of filtration of the blood in the Bowman's capsule is ultrafiltration (or glomerularfiltration), and the normal rate of filtration is 125 ml/min, equivalent to ten times the blood volume daily.
Fluid in the filtrate entering the proximal convoluted tubule is reabsorbed into the peritubular capillaries, including approximately two-thirds of the filtered salt and water and all filtered organic solutes (primarily glucose and amino acids).
This hypotonic filtrate is passed to the distal convoluted tubule in the renal cortex.
Feeds |
Contact