What Are the Characteristics of Glomerular Capillaries?

Update Date: 2024-06-07 Source: Network

The glomerular capillaries are mainly distributed around the glomerulus and the kidney, serving as a channel for supplying blood and nutrients to the kidney and glomerulus. Additionally, these capillaries also contain special substances secreted by the kidney. Their structure is relatively complex, and their main characteristic is being straight, short, and thick, enabling them to perform a filtering function and primarily connect with the capillaries of each lobule.

1. What are glomerular capillaries?

The glomerulus is a spherical network of capillaries. The afferent arteriole enters the renal capsule from the vascular pole and divides into 5 to 8 branches, which then subdivide into numerous looped capillaries. These capillaries coil to form 5 to 8 capillary lobules or segments, with mesangial tissue connecting the capillaries within each lobule. There are few anastomoses between the capillaries. The capillaries of each lobule converge into larger vessels, which then merge with the small vessels of other lobules to form the efferent arteriole, which exits the glomerulus from the vascular pole.

2. Compared with capillaries in other parts of the body, glomerular capillaries have two major characteristics:

(1) Straight, short, and thick: The afferent arteriole of the glomerulus is straight, short, and thick, while the efferent arteriole is curved, thin, and long. This results in the internal pressure of the glomerular capillaries being 2 to 3 times higher than that of ordinary capillaries, a feature particularly evident in the renal cortical nephron. This structure clearly facilitates the filtering function of the glomerular capillaries and the formation of primary urine. On the other hand, it also makes it easier for some special substances (such as immune complexes, macromolecules, and blood cells) in the blood flow to deposit on the capillary wall and cause damage.

(2) Complex structure: The wall of the glomerular capillaries has a complex structure, consisting of endothelial cells, a basement membrane, and epithelial cells. This ensures the selective filtering function of the glomerular capillaries and also allows some special substances in the blood flow to be filtered out.