Final answer:
The glomerular capillaries in the kidneys are the ones with both afferent and efferent arterioles, and they are part of a unique vascular arrangement constituting a portal system connected by an arteriole.Option 4 is the correct answer.
Step-by-step explanation:
The capillaries in the body that have both afferent and efferent arterioles are the glomerular capillaries of the kidneys. Blood enters the glomerulus through the afferent arteriole where it gets filtered. The filtered blood then exits the glomerulus through the efferent arteriole, which leads to the peritubular capillaries and vasa recta. This constitutes a unique portal system, as typically portal systems involve two capillary beds connected by a venule, but in this case, the connection is via an arteriole. Moreover, these glomerular capillaries are fenestrated capillaries, which supports their filtering function in the renal system.
The renal system's glomerular capillaries in the kidneys present a distinctive vascular arrangement with both afferent and efferent arterioles. Blood enters the glomerulus through the afferent arteriole, undergoing filtration, and then exits through the efferent arteriole, leading to the peritubular capillaries and vasa recta. This forms a unique portal system, deviating from the conventional model involving venous connections. Notably, glomerular capillaries exhibit fenestrations, enhancing their filtration capacity. This intricate setup ensures the efficient filtration of blood in the kidneys, allowing for the removal of waste products and the regulation of fluid balance—a crucial aspect of renal function contributing to overall physiological homeostasis.