The cortical substance of the kidney is a complex structure filled with various components that carry out tremendous work to clean the entire body of harmful substances and excess fluid. Any failure in this debugged system can lead to serious problems, complex diseases, and sometimes organ transplantation.
What are the kidneys made of?
The kidneys are bean-shaped organs in the human body. Each one is the size of a fist. They are located just below the chest, on both sides of the spine.
There are mainly three areas of the organ. In the kidney there is a cortical substance located approximately in the middle, the outer shell (capsule) and the inner layer (medulla). The membrane is a transparent membrane lining the outer part of the organ, which acts as a protection against infections and injuries. The medulla located inside consists of dark tissue and contains eight or more triangular structures known as renal pyramids. The cortical substance is between these two layers. It usually has a paler color with a yellowish tint and stretches down between the pyramids like the sun's rays.
What it is
People, as a rule, have two kidneys, the main duty of which is the purification of blood from waste products and their removal outside the body. The thickness of the cortical substance of the kidney is about 5-6 mm and is usually regarded as a kind of insulating layer. This is not the outermost coating, but in fact it is located and not in the middle. You can imagine this part as the albedo of an orange (white spongy pulp) - it extends below the peel, but above the fruit. Many important infrastructure facilities of the body begin, and sometimes end here.
The layer consists mainly of nephrons, which are the main labor force of the organ, as well as blood vessels, twisted together in tiny glomeruli. There is also a number of renal tubules. The structure of the cortical substance of the kidney is such that the entire internal system of the structure acts as a filter. Many elements entering there undergo careful screening, which allows the body to carry out its work.
The proper functioning of the layer is important for the general state of health, which makes this area important. Without it, many processes and systems would be very fragile and potentially unstable. Therefore, problems with the bark or weak spots on any part of its surface can lead to a number of potentially life-threatening diseases.
What does it consist of
The cortex of the kidney contains millions of units known as nephrons. Most of them (85%) are contained there. The remaining 15% are called juxtamedullary, and their glomeruli are located in the peripheral region of the layer, at the junction with the medulla, and the Henle loops included in their composition are already found outside this zone.
Each nephron contains a body consisting of what is called a glomerulus (glomerulus). This structure is a tiny node of blood vessels, the walls of which are dotted with small holes. They are too small to allow blood cells to escape, but water, minerals, nutrients and other tiny molecules can pass into the urinary space. This formation is enclosed within a structure known as the Bowman capsule.
Filtered through the glomerulus, the fluid (primary urine) passes through the renal tubules (consisting of the proximal tubule, Henle loop, passing into the distal convoluted tubule), where the most important nutrients, together with a large amount of fluid, are reabsorbed back into the blood. There, certain chemicals (including ammonia) are released into the remaining fluid, so secondary urine is formed, it is concentrated in collecting tubes so that it passes through the ducts into the renal pelvis, ureter, and then into the bladder.
Main responsibilities
The main processes of the cortical substance of the kidney and the functions that it performs are as follows:
- In the glomeruli, the plasma fluid is filtered.
- Renal columns penetrate between the pyramidal structures of the cerebral layer, thus providing blood supply to the entire organ.
- Actively involved in the metabolism of the kidneys, creating ammonia for titration of the acidity of urine and thus helps in acid-base regulation.
- Helps in the excretion of diluted or concentrated urine, which is very important for maintaining blood volume.
- It is the site of reproduction of erythropoietin - a special hormone that stimulates the production of red blood cells.
Filtering process
It begins in the nephrons, each of which is supplied with blood through its own afferent arteriole. It enters the glomerulus, consisting of a bunch of intertwined capillaries. This formation is surrounded by a Bowman capsule, in which the filtration process occurs under pressure. This causes the serum to pass through the naturally perforated capillaries, and the blood cells, being too large for the holes, remain inside. As soon as the liquid crosses the walls of the vessels, it begins to be called the filtrate.
It is important to understand that with the slightest damage to this system, all elements that are removed from the body to the outside remain in the blood, continuing to circulate throughout the body and causing significant damage to the cortex of the kidney.
Then the filtrate enters the renal tubules, in which the process of re-filtration takes place: the return of nutrients and water back to the bloodstream, the removal of toxins, the concentration of the remaining fluid (urine) and its further removal from the body.
Functions of the cortical and medulla of the kidney
Both areas are the main parts of the organ, but vary in texture.
Cortical layer:
- is the outermost part of the organ;
- is engaged in the excretion of urine;
- it contains renal corpuscles and tubules;
- produces erythropoietin.
Cerebral substance:
- is the inner layer;
- involved in the concentration of urine;
- contains loops of Henle and collecting ducts;
- not involved in the production of erythropoietin.
In addition, both parts help in the process of maintaining plasma osmolarity, ion composition, blood components and filtration.
Common problems
Cortical matter is the outer part of the kidney where urine is produced. With prolonged illness (chronic renal failure), if the organs work less than 20% of their capabilities, atrophy is detected.
Many diseases can affect the structure and function of all parts of the cortical substance of the kidney.
The glomeruli are usually very susceptible to infections and autoimmune disorders (glomerulonephritis, SLE), and radioactive substances and certain medications can harm the tubules. When problems of this kind arise, the cortical substance may be damaged and cease to fully cope with the cleaning or even stop the filtering process. These cases lead to a number of serious medical problems.
Diagnostics
Problems in the cortical substance of the kidney are usually diagnosed using abdominal ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI). Laboratory tests of blood and urine can also give the doctor some general idea of how well organs function. If the indicators indicate serious internal changes, a biopsy may be needed to help locate the disease. At the same time, tissue samples are taken from the cortical layer to see the whole picture and make an accurate diagnosis. Treatment usually begins as soon as problems are detected.
Serious irreversible damage to the cortex of the kidney may require dialysis treatment. For example, in the last stages of renal failure, when most of the glomeruli irrevocably atrophy and the filtration rate decreases significantly, this method helps to cleanse the body of toxins and bring them out.