Final answer:
The kidneys in mammals serve as the main osmoregulatory organs. They maintain the balance of bodily fluids through filtration and secretion, while also regulating blood pressure and glucose metabolism.
Step-by-step explanation:
The kidneys are the main osmoregulatory organs in mammalian systems. Their primary role is to maintain the homeostatic balance of bodily fluids by filtering and secreting metabolites and minerals from the blood and excreting them as urine. The kidneys also play a crucial role in regulating blood pressure, glucose metabolism, and erythropoiesis.
The structure of the kidneys consists of three distinct regions - the cortex, medulla, and pelvis. The functional unit of the kidney is the nephron, which actively filters blood and generates urine through three steps: glomerular filtration, tubular reabsorption, and tubular secretion.