The parts and function of the kidneys play an important role in how the body operates by ridding the body of harmful toxins, urea and waste. The kidney is also responsible for balancing bodily fluids, producing hormones that regulate blood pressure and control the production of red blood cells, and producing a form of Vitamin D. Aside from the lungs, the kidneys are the only paired organs in the body that operate independently to keep the body working efficiently.
Blood filtration is the primary function of the kidney. Oxygen and glucose-rich blood comes to the kidney through the renal artery. Incoming blood is contaminated with prescription and illegal drugs and high levels of salt. Because of the difference in diameters between the incoming and outgoing arterioles, the blood is under high pressure. This is the only way the blood filtration process will work effectively. People who have low blood pressure can develop kidney disease, which can lead to kidney failure. The kidneys then transport clean blood to the right side of the heart through the renal vein. The processed blood is clean and contains the extra water and salts excreted by the kidney as a byproduct of its major functions.
The cortex is the outer section of the kidney and contains the medulla, which has several medulla pyramids. These pyramids filter out nearly 43 gallons of water a day through millions of tiny structures called nephrons. The 10,000 nephrons in each kidney contain a cluster of small vessels called glomerulus capillaries that force pressurized blood through a double-walled filtration membrane called the Bowman’s capsule, which will filter out not only the water in the blood plasma, but salt, glucose and urea. The filtration process then flows through the proximal convoluted tubules, which filters re-usable glucose back into the bloodstream. Glucose that is not absorbed passes into the urine and is an indicator of diabetes and kidney disease. Salts are absorbed by the distal convoluted tubules. The excess water is reabsorbed through the part called the loop of Henlé and then filtered toward a collecting duct that produces urine. Tubular re-absorption can vary depending on the body’s needs for certain nutrients.
The pelvis stores the urine created from the cortex system. The pelvis then sends the urine to the bladder via the ureter. The pelvis is the area of the kidney commonly afflicted with kidney stones, masses of crystallized salts that block the passage of urine from the medulla to the ureter. Medications and changes to the diet can prevent the development of kidney stones. Large stones that may be too big to pass through the ureter without causing severe damage are removed via surgery.