Kidney, Organ Excretion System in Humans that Dispose of Metabolism Waste

The excretion system in humans is a system that processes the disposal of residual substances resulting from metabolism. Metabolic waste products consist of carbon dioxide (CO2), water (H20), ammonia (NH3), urea, and bile substances. These metabolic waste products must be removed from the body because they are poisonous and can cause disease. In addition to the lungs, skin and liver, the kidneys are one of the important organs in the excretion system in humans. The kidneys are located on both sides of the spine, precisely in the back of the abdominal cavity, under the rib cage. Kidney is an excretion organ that is shaped like red beans and reddish brown. Humans have a pair of kidneys, which are on the left and right. The right kidney is slightly lower than the left kidney because it is near the liver. Each kidney is about 10-12 cm in size, about the size of a fist.

Role of the Kidney in the Excretory System

In addition to filtering blood, controlling body fluid balance, and maintaining electrolyte levels in the body, the kidneys are very closely related to the excretion system in humans, which is tasked with removing bodily wastes and poisons. Blood entering the kidney will be filtered, as well as bodily fluids. The kidneys are also tasked with maintaining the body's water, salt and mineral levels within normal limits. Filtered blood will flow back to other organs in the kidneys. And filtered waste substances will then be discharged through urine collected in the renal pelvis (renal pelvis). Then, the ureter will move urine into the bladder, where the urine is stored. Finally, urine runs from the bladder and exits the body through the urinary tract. Kidney is an important organ that is part of the urinary system, and has many functions, namely:

• Excreting (excreting) metabolic waste from the body. The kidneys filter toxins, excess salt, and urea, as well as nitrogen-based waste that is created from cell metabolism. Urea is processed in the liver and transported through the blood to the kidneys for disposal.
• Balancing fluid and electrolyte levels. Because the kidneys are key in the formation of urine chemistry, the kidneys will react to changes in water levels in the body throughout the day. When water intake decreases, the kidneys will adjust and hold water in the body so that the body does not experience a lack of fluids.
• Regulate blood pressure. The kidneys need constant pressure to filter blood. When blood pressure drops too low, the kidneys will increase blood pressure. This is done by producing angiotensin, which can constrict blood vessels and retain salt and water in the body. This process will help blood pressure return to normal.
• Red blood cell regulation. When the kidneys don't get enough oxygen, the kidneys will send an emergency call in the form of erythropoietin, a hormone that stimulates bone marrow to produce more oxygen-carrying red blood cells.
• Helps absorb calcium and maintain bone health, by producing the hormone calcitriol.
• Regulate acid levels in your body.

Given the importance of the kidney organ in maintaining overall bodily functions, it is also important for you to maintain kidney health. Some diseases that can interfere with the work of the kidneys are hypertension, kidney inflammation, acute and chronic kidney failure, to kidney tumors. In addition, diabetes can cause diabetic nephropathy. These conditions can disrupt the work of the kidneys and the excretory system, so that toxins and waste in the body become accumulated in the blood and cause various complications.