Did you know that about 200 liters of fluid are drained by the kidneys every day? With this workload, the kidney expels toxins, excess ions and metabolic wastes with the urine. Other substance that is needed by the body that is filtered by the urine is returned back to the blood.
The kidneys are the body’s major excretory organ. They continuously work to give the body a much needed balance between acids and bases, salts and water. The kidneys do their job very efficiently yet it is less appreciated. A person only appreciates the importance of the kidneys when they have already malfunctioned and the body becomes slowly contaminated.
The kidneys are not only involved in excretory functions but also in regulating chemical makeup and volume of the blood. During prolonged fasting, the kidneys are involved in gluconeogenesis or the process of creating new glucose. It is defined that way because normally, the body gets glucose from carbohydrates. However, in prolonged fasting the body has no supply of carbohydrates; hence it uses fats or proteins to create glucose.
The kidneys also produce two very important hormones, erythropoietin and renin. The hormone erythropoietin stimulates the bone marrow to produce red blood cells and the hormone renin helps in regulating kidney function and blood pressure. Lastly, the kidneys are also involved in metabolizing vitamin D into its active form.
Location and External Anatomy
As one examines the kidney, is assumes a shape comparable to a bean. It lays superior lumbar region, retroperitoneal position. The lower part of the rib cage offers some form of protection to the kidneys. An interesting point to note is that the right kidney is positioned slightly lower than the left kidney. This is due to the fact that the live crowds the area, pushing the right kidney down. The average mass of an adult kidney is approximately 5 ounces or 150g. A vertical cleft, known as the renal hilum leads to the internal space of the kidney known as the renal sinus. The lateral aspect of the kidney is convex and the medial surface of it is concave.
On top of the kidney is another organ, the adrenal gland which is not related to the kidney, in terms of function.
Layers of Supportive Tissues
Surrounding each kidney are three layers of supportive tissue, the fibrous capsule, the perirenal fat capsule and the renal fascia. The fibrous capsule’s task is to ensure that infections from surrounding regions will not reach the kidneys. The perirenal fat capsule acts as a shock absorber against blows and helps in anchoring the kidney to the posterior body wall. The renal fascia is the main system that anchors the kidneys and the adrenal glands to the surrounding tissues. It is made up of layers of dense fibrous connective tissue.
The perirenal fat capsule may not be the main anchoring system of the kidney but it has a vital role that ensures the kidney stays in its normal anatomical position. If the amount of fat decreases, an event called renal ptosis or the dropping down of the kidneys to a lower position happens. When this event happens, the ureter may become kinked, causing obstruction and problem to the body.