The kidneys are two small organs situated in the direction of the back of the abdomen, shut to the base of the rib cage. There is one at each side, the left kidney being slightly higher than the right. Their function is to remove waste products from the blood and so regulate salts, minerals and fluid levels in the body.
The kidneys are oval constructions, red/brown in color with a tube called the ureter that runs down from each kidney to the base of the bladder. The renal aorta, branching from the aorta from the heart, brings oxygenated blood to them and the renal vein requires deoxygenated blood away. There are two main parts to the construction of the within of the kidney, the internal known as the medulla and the outer known as the cortex. The renal artery hauling oxygenated blood to the kidney, branches through the medulla and then divides in to many arterioles and capillaries within the cortex. Here, the tiny capillaries branch more and form coils, with each coil surrounded by frameworks called the Bowman's capsule. The Bowman's capsule is a cup like framework that prospects to small tubules that pass back through the cortex of the kidney into the medulla, and finally join the ureter that exits the kidney and prospects down to the bladder.
The method by which the kidney filtrations waste products, is decided by the blood pressure in the coiled capillaries being high soon after heading through so many twists and spins. In addition, the renal aorta from which they branch being near to the heart, heightens the pressure. This pressure causes fluid to filtration out through the capillary walls and enter through the porous walls of the Bowman's capsule where it collects. The filtration fluid contains water, glucose, amino acids, salts and nitrogenous waste. The greater particles in the blood such as greater proteins and the red blood cells on their own are too big to pass through this filtering stemming process.
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As the filtration fluid goes by down the tubules from the Bowman's capsule and back through the medulla of the kidney, all amino acids, glucose, some of the salts and much of the water are absorbed back into a community of capillaries adjoining the tubule. This re-absorption stops the loss of useful substances that have been filtration from being squandered. The remaining fluid, now called urine, contains only the waste products such as salts, extra water and other waste substances. The urine goes down in the direction of the ureter where more water is re-absorbed. If the blood is too dilute then less is absorbed but if the blood is concentrated then more is absorbed. Contractions in the ureter carry the urine down from the kidney to the bladder. When the kidneys become dysfunctional, kidney dialysis becomes necessary. In dialysis, the blood goes through a semi-permeable membrane in the dialysis machine that allows waste products to be pool filtered from the blood. mainly because waste products construct up constantly, it is typically necessary to have dialysis three times a week, or nightly depending on the type of dialysis used.
