As the filtrate flows it is modified by cellular transport processes some result in reabsorption into the tubule, some other substances are secreted from the capillaries into the tubule. The important point is that this reabsorption and secretion can be regulated giving rise to homeostatic control of water and electrolytes. Overall process-Plasma enters the afferent arteriole and goes to the glomerular capillaries. As for the most capillaries the glomerular capillaries are comprised of endothelial cells. Filtration occurs here via the same forces we discuss driving net filtration at other capillary beds.
Major difference is that filtration is favors.
Filtrate then moves to the tubule. There is great heterogeneity in function along the tubule. The glomerulus, proximal and distal tubules are found primarily in the cortex. The loops of Henle in the medulla. As will be discussed later, the osmotic environment surrounding the cells here are very different.