Posted by For my STEAM project, I chose to focus on the objective “describe the function of kidneys” and how kidney stones disrupt their function.
The main functions of the kidneys are to regulate water volume in the body; maintain acid-base balance; eliminate waste from metabolic processes, toxins, and medications; synthesize erythropoietin (EPO) and renin; activate vitamin D; and create glucose as needed. Kidney stones disrupt these functions and can damage the kidney.
The Basic Mechanisms of the Kidney
The kidneys are bean-shaped organs located on the left and right sides of the midsection of the torso. They are slightly tucked under the ribcage and located close to the spine. The renal artery carries oxygenated blood and fluid into the kidney for filtration and fluid balance, and the filtered blood leaves, deoxygenated, via the renal vein to go back to the heart (Cleveland Clinic, 2024). This blood enters the renal medulla and goes through a microscopic filtering unit called the nephron that houses the glomerulus and long renal tubule (Nazarian et al., 2025). The glomerulus takes the blood and filters out the large blood plasma protein molecules, allowing smaller nutrients and water molecules to filter into the long renal tubule. The fluid inside the renal tubule enters the proximal convoluted tubule, where solutes are either reabsorbed or secreted. The filtration then enters into the nephron loop, also known as the loop of Henle, a u-shaped track (Nazarian et al., 2025). The descending nephron loop passively diffuses water molecules, concentrating the filtrate, and the ascending nephron loop removes sodium, chloride, potassium, and other ions through active transport. The nephron loop creates urine and monitors the concentration of the urine based on the body’s hydration needs, acid-base balance, and other factors (Nazarian et al., 2025). The urine ascends into the distal convoluted tubule and collecting duct, where the finishing touches are added to the urine composition and the urine becomes more concentrated. The distal tubule finishes the acid-base balance and regulates the amount of sodium, potassium, and other ions in the urine (Nazarian et al., 2025). The finished urine then enters the renal pelvis to exit through the ureter into the bladder and eventually out of the body.
What are Kidney Stones?
Nephrolithiasis, commonly known as kidney stones, is a buildup of hardened minerals and salts in the kidney. Symptoms of kidney stones are moderate to severe pain in the back, groin, or stomach, nausea and vomiting, fever, and an urge to urinate. Urine is most often brown or red from blood in the urine, cloudy, and foul-smelling (Weinberg, 2024). Kidney stones are crystallized minerals that vary in size and shape, ranging from micrometers to millimeters, smooth to spiky (Nazarian et al., 2025), with larger stones causing more complications. They occur when the urine becomes too saturated with minerals like calcium phosphate (CaP), calcium oxalate (CaOx), the ionic salt uric acid, and not enough liquid to move them out of the body (Weinberg, 2024). These minerals crystallize and harden inside the kidney and, over time, can become larger as more minerals are deposited, forming a stone. These deposits are often located in renal tubules, near the site of the distal tubule where urine concentration finishes, and the renal pelvis, causing blockages that prevent urine from leaving the kidney. These blockages cause pain and stretching of the renal pelvis and ureter and can cause damage to these structures (Nazarian et al., 2025). The kidney stone prevents the kidney from maintaining its normal functions of filtering the blood, maintaining acid/base balance, and total water volume levels in the body. The urine pH can also be highly acidic depending on the stone composition and the amount of uric acid present (Weinberg, 2024).
Treatment
Once kidney stones have developed, it is common for most patients to experience another stone episode, with “50% developing one in the first five years and 74% within 20 years” (Nazarian et al., 2025). The exact cause of developing kidney stones is not known, but dehydration, diabetes, family history, diet, infections, obesity, and other factors elevate risks. Treatments for kidney stones include a change of diet, increased hydration, pain medications, and alpha blockers that work to relax and widen the urinary tract, making it easier for a stone to pass. In cases when the stone is too large, surgical removal or lithotripsy can be used. Lithotripsy uses ultrasonic waves that target the stones and break them into smaller pieces that can be naturally expelled through urine (Mayo Clinic, 2025). For those with severe recurrence of kidney stones, this can cause permanent kidney damage that can lead to chronic kidney disease and kidney failure, but this is exceedingly rare (Hassan et al., 2024). When this occurs, the kidneys cannot filter blood properly, and a buildup of toxins, minerals, water, and other metabolic wastes causes systemic problems. The only way to mitigate these issues is through dialysis, a machine that mechanically cleans the blood, or a kidney transplant operation (Hassan et al., 2024).
References
Cleveland Clinic (2024). Renal vein. Retrieved from https://my.clevelandclinic.org/health/body/renal-vein
Mayo Clinic (2025). Kidney stones. Retrieved from https://www.mayoclinic.org/diseases-conditions/kidney-stones/diagnosis-treatment/drc-20355759
Hassan, H. C., Tunnicliffe, D. J., Loyd, L., Mullan, A., Wickham, I., Cashmore, B., Jose, M., Mallett, A. J. (2024). Kidney failure from kidney stones: an ANZDATA study. Nephrology Dialysis Transplantation, 40(2), 320-328. https://doi.org/10.1093/ndt/gfae137
Nazarian, R., Lin, N., Thaker, S., Yang, R., Wong, G. C. L., & Scotland, K. B. (2025). What causes calcium oxalate kidney stones to form? An update on recent advances. Uro, 5(1), 6. https://doi.org/10.3390/uro5010006
Weinberg, D. M. (2024). Kidney stone. Salem Press Encyclopedia of Health.
Danielle did an excellent job on thoroughly explaining kidney stones in her STEAM project. The project covers the objective to “describe the function of kidneys” and how kidney stones disrupt their function. She effectively represented this in her art project by creating a hand sewn model of a kidney, with buttons representing kidney stones causing a blockage.
The kidneys are organs responsible for many functions, including filtering blood, regulating fluid balance, and maintaining acid-base levels. Blood enters through the renal artery into the kidneys and is filtered by nephrons, which include the glomerulus and renal tubules. Water and solutes are reabsorbed or secreted as the filtrate moves through the tubules, which forms urine that exits through the ureter to the bladder.
Kidney stones are hard mineral deposits that form when urine becomes overly concentrated with substances like calcium or uric acid. These stones have different shapes and sizes and can block urine flow and cause pain, blood in the urine, and infection.
Treatments for kidney stones include hydration, dietary changes, and medications like alpha blockers. Larger stones can also require lithotripsy or surgical removal. Although it is rare, repeated stone formation can lead to chronic kidney damage and cause kidney failure.