The Function of a Kidney
The kidney is essential to the regulation of the body's fluid balance and acid-base balance. The kidney contains about 1 million nephrons, each of which consists of a glomerulus and a tubule that drain urine into the renal pelvis. Capillaries feed each glomerulus and surround each tubule.
About 140 liters of fluid pass from the glomeruli into the tubules each day; 99% of this salt and water solution is reabsorbed into the surrounding capillaries. The tubules also reclaim other essential substances, such as amino acids, glucose, bicarbonate, calcium, and phosphorus and, when necessary, add potassium and hydrogen to the tubular fluid.
Each glomerulus acts as a filter, allowing the passage of certain dissolved substances from the bloodstream into the tubule, but preventing cells and large proteins from crossing over.
Glomerular Filtration Rate (GFR)
Amount of blood filtered by the kidneys per minute.
- Normal: 100–125ml/min
Amount of plasma filtered free of creatinine (a waste product) per minute.
- Normal = 100–120ml/min
- Normal plasma creatinine = 0.5–1.4mg/dl
- Serum creatinine >5 mg/dl impairs normal bodily functions
BUN (blood urea nitrogen)
Blood level of urea (waste product of protein metabolism).
- Normal = 8-20mg/dl
Slightly elevated excretion of albumin (protein) in the urine; earliest sign of kidney damage.
- Normal = <30mcg/mg protein/24 hrs
- Microalbumin range: 30–300mcg/mg protein/24 hrs
- Improving blood glucose control
- Controlling blood pressure (<130/80 standing)
- Decreasing dietary protein intake
For more information
Additional information on kidney function HERE.
©Gary Scheiner MS, CDCES – Integrated Diabetes Services. May be reproduced and used for patient education, but not sold.