The kidneys often go underappreciated, but they truly deserve our admiration. The more you learn about these remarkable organs, the more you’ll realize the importance of preserving their health.
An alternative term for kidneys is “renal,” a word frequently used when discussing kidney-related topics such as renal function or renal failure. Whenever you come across the term “renal,” you’ll instantly recognize it pertains to kidneys.
Kidneys are two bean-shaped organs, each approximately five inches in length, three inches in width, and one inch in thickness. They reside in your back on either side of your spine, resembling fists in size and weighing between four to six ounces each. Positioned above your waist, the left kidney rests slightly higher and is marginally larger, while the right kidney is somewhat lower and smaller to accommodate the presence of the liver. These vital organs are safeguarded by the lower ribs.
Within the kidneys, there exist microscopic units known as nephrons, where the essential process of filtering excess fluids and dissolved particles takes place. Each kidney houses between 1 and 1.3 million nephrons.
While many believe that the sole function of the kidneys is urine production, their responsibilities extend far beyond that. In addition to expelling surplus fluids and water from the body, the kidneys undertake various crucial roles:
The kidneys’ fundamental operation commences when you consume food and beverages. After the body extracts the necessary nutrients, the remaining substances become waste products. Some of these waste products enter the bloodstream and require filtration. The blood circulates through the body with every heartbeat, and it’s the kidneys, with their millions of nephrons, that undertake the task of filtering and purifying the blood, eliminating excess fluids in the process. These surplus fluids and waste materials are transformed into urine, which travels from the kidneys through the ureters to the bladder and eventually exits the body through the urethra.
However, waste removal is just one facet of the kidneys’ duties. Apart from filtration, the kidneys meticulously monitor the levels of chemicals, salts, and acids in the blood. Within the nephrons, specialized sensors keep tabs on sodium, phosphorus, calcium, and potassium levels. When these levels become elevated, the kidneys send signals to remove the excess substances from the bloodstream for eventual elimination.
Another vital responsibility of the kidneys is overseeing and regulating specific bodily functions. For instance, the kidneys secrete an enzyme called renin to manage blood pressure, release the hormone erythropoietin to stimulate red blood cell production in the bone marrow, and produce calcitriol to fortify bone health.
Each kidney contains approximately one million miniature filtration units known as nephrons, comprising glomeruli and tubules. The glomerulus consists of specialized capillary loops responsible for filtering water and small particles from the blood. Subsequently, waste materials and excess fluids traverse the tubular structures of the nephrons, undergoing several processes to convert them into urine. These tubules culminate in the collecting duct, where urine is funneled into a sac-shaped region called the renal pelvis. Each kidney is connected to the bladder by a ureter, through which urine flows down to the bladder before being excreted from the body via the urethra.
