Final answer:
The basement membrane in the filtration membrane acts as a selective barrier, preventing the filtration of medium-to-large proteins while allowing smaller molecules to pass. It is also responsible for providing structural support and maintaining flexibility. The membrane's charge contributes to the exclusion of negatively charged substances, hence regulating the composition of the filtrate.
Step-by-step explanation:
Function of the Basement Membrane in the Filtration Membrane
The basement membrane plays a critical role within the filtration membrane, which is part of the nephron in the kidney. It is situated between the capillary endothelial cells and functions as a selective barrier that prevents the filtration of medium-to-large proteins, such as globulins. Its primary function is to permit the passage of small molecules while restricting larger ones, contributing to the formation of a filtrate devoid of cells and large proteins. With fenestrations allowing for passage based on size and electric charge, the basement membrane adds another layer of selectivity, repelling negatively charged substances while allowing positively charged substances to pass more readily. Additionally, it provides structural support by binding the endothelium to the connective tissue, thus contributing to the nephron's ability to filter blood and form urine.
Within the glomerulus of the renal corpuscle, fenestrations in the endothelial cells and the filtration slits of podocytes, along with the membrane charge, contribute to the overall regulation of filtration. The basement membrane syncs with these structures to ensure that the resulting filtrate is finely tuned, which is critical for proper kidney function and filtration.
The strength and flexibility of the basement membrane, as well as its permeability, are vital for its functionality. These physical properties allow it to withstand the pressure yet provide a filtration mechanism that ensures the selectivity of substances entering the nephron for processing into urine.