Final answer:
The kidneys filter blood to remove waste and the urinary bladder stores urine. The glomeruli within the kidneys filter based on particle size and nephrons, as a part of the renal system, process the filtrate to eventually create urine.
Step-by-step explanation:
The kidneys filter blood to remove waste, and the urinary bladder actually stores urine until it is released from the body. The urinary system is equipped with about 2 to 3 million tufts of specialized capillaries called the glomeruli, which are crucial for the blood filtration process. These glomeruli filter blood largely based on particle size, retaining large elements such as blood cells and proteins like albumen, while allowing smaller molecules to pass through and form a filtrate. The nephron is the fundamental structural and functional unit of the kidney, that includes the glomerulus, and the tubular structures that modify the filtrate, ultimately leading to the production of urine.
An important fact to note is that the glomeruli produce approximately 200 liters of filtrate daily, but only a fraction of this becomes the waste product known as urine. The kidneys' role in the formation of urine includes the processing of a huge volume of blood, out of which less than two liters of waste is excreted as urine. Moreover, each kidney possesses up to a million nephrons, which are tiny, tube-shaped structures that individually process small amounts of fluid and waste taken from the blood vessels.
The collected fluid and waste by the nephrons move through the ureters to the urinary bladder, where urine is stored. Eventually, urine is excreted from the body through the urethra. This entire mechanism underscores the main function of the urinary system, which is to filter blood and to manage waste elimination along with the regulation of various bodily substances.