Kidneys

3945
Abraham McLaughlin
Kidneys
Location of the kidneys in humans

What are kidneys?

The kidneys they are very important organs of the human body. They belong to our urinary system, they are two, they have a shape very similar to that of a bean and they work in the filtration of our blood and in the elimination of waste from our body.

The kidneys are one of the most important organs of the urinary system and we can locate them by placing our hands on our hips, going up until we find the last pair of ribs and directing our thumbs towards the center of the back..

The urinary system, as well as any other organ system in our body, is fundamental to our life. Specifically, it is in charge of the important task of eliminating metabolic waste from our cells..

What is metabolic waste?

Each of our cells requires certain components daily to survive, the most important being water, oxygen and nutrients derived from the digestion of what we eat.

Most of these components travel in our blood, which delivers them to each of our organs and tissues, from where they are distributed to all the cells that make them up..

At the macroscopic level we can say that not everything we eat as food is processed by our digestive system, so that what we cannot digest is eliminated with the feces..

At the microscopic level, the same thing happens, since the cells take in the nutrients that are delivered to them, process what they can and return to the blood what they are not able to metabolize further and that, if they accumulate, can be toxic. This is what we know as metabolic waste.

The accumulation of these wastes in our body is also harmful for us, and it is the task of the urinary system filter the blood, extracting from it as much waste as possible, as well as excess fluids in this.

Besides kidneys, the urinary system is made up of ureters, which are two tubes that connect the kidneys with the bladder, an organ that serves as a storage site for urine before expelling it through the urethra.

Parts of the kidneys (anatomy)

Basic anatomy of a human kidney. Each of our two kidneys has a cortex and a medulla. In the cortex are the functional units, known as nephrons, which are responsible for the filtration of blood

In our body there are two kidneys, which are in the back of our body, more or less in the lower area of ​​our back..

They have a very characteristic shape, as they look like two large beans, although they are only between 10 and 12.5 centimeters long. They are generally reddish or brown in color and are associated with a large number of blood vessels entering and leaving.

Outer layers of the kidneys

The kidneys are enveloped by three layers:

  • The renal fascia is the outermost and represents a kind of capsule formed by a very resistant layer of connective tissue..
  • The adipose capsule, also known as the perirenal fat capsule, is the second layer and is one of those that facilitates the anchoring of the kidneys in place..
  • The renal capsule is the innermost layer and is a very fibrous and transparent layer that works to protect the kidneys against infections or trauma..

Inner regions

In the inner region, that is, the region that is contained in these three outer layers, each kidney has three well-defined regions:

  • The cortex, which is the outermost region.
  • The medulla, which is in the center.
  • The renal pelvis, which is located at a site in the kidney called hilum, that corresponds to the middle of the concave edge of the kidney, that is, where it is depressed to acquire the shape of a bean; the renal hilum enters and leaves the blood vessels and nerves associated with each kidney and is also the site from which the ureters exit.

The functional units of each kidney are known as nephrons and these are found in the renal cortex, which gives this area a grainy appearance.

The medulla is made up of a series of pyramidal masses known as kidney pyramids, among which are the renal columns, what are the sites where the blood vessels pass.

Kidney glands

The kidneys are associated with glands that are found in their upper part, these are known as the adrenal glands and are responsible for the production of different hormones that are very important for our life

On each of our kidneys settle small glands that are responsible for the production, mainly, of sex hormones and another very important hormone called cortisol, that helps us respond to stress.

Kidney functions

The functions of the kidneys are closely related to those of the urinary and excretory system. Among these, we can highlight the following:

  • They help to maintain the body balance of fluids, salts and other molecules, the most important being sodium and potassium.
  • They participate in the elimination of urea through the urine; Urea is a molecule that results from the metabolism of meats and certain protein-rich vegetables that we eat every day.
  • They work in the production of different hormones, that is, they have endocrine functions. Among these hormones is erythropoietin, that works in the regulation of the formation of red blood cells, which are the cells in charge of transporting oxygen in the blood.
  • The adrenal glands, closely associated with the kidneys, also have important endocrine functions, such as the production of some hormones necessary for the development of sexual characteristics and reproduction..
  • Blood pressure, acid-base balance and the conservation of fluids in our body depend on the proper function of the kidneys..

Kidney function

The blood in our body is constantly transported to the kidneys throughout our lives. Inside these small organs, the nephrons, which are the functional units, are responsible for extracting water and other substances from the blood (metabolic waste, some nutrients, etc.).

Much of the water and nutrients are again discharged into the blood, while metabolic waste and excess water is retained in the nephrons forming the liquid we know as urine.

From the nephrons, which are found in the renal cortex, the urine that is formed passes the region known as the renal pelvis, where it is directed towards the bladder through the ureter associated with each kidney.

The bladder participates in the accumulation and storage of urine, until the nerve signals tell it that it is time to empty and that it must send this liquid towards the urethra, which finally allows the expulsion of waste out of our body.

Kidney disease

There are many diseases related to the kidneys and these tend to seriously compromise the health of the human body, since the accumulation of waste, fluids and salts can have serious physical problems.

Many common conditions involve infections due to the presence of microorganisms, especially in patients who have suffered other diseases such as peritonitis or a ruptured gallbladder.

Kidney stones (stones)

Kidney stones

These are formed when excess salts do not leave the nephrons in the renal cortex, but accumulate inside, forming solid agglomerates that must be dissolved..

Generally, these stones can cause certain discomforts, including difficulty urinating. Different medications are prescribed to dissolve these stones, so that they can be eliminated normally in the urine..

However, the removal of "dissolved stones" is often accompanied by intense pain, especially in men..

Chronic kidney disease

It is another very common condition. It is a long-term condition and usually worsens over time. It is caused by high blood pressure, which directly affects the functioning of the nephrons by causing damage to the blood vessels and capillaries through which the blood circulates inside..

When the damage is very serious, that is, when the kidneys cannot do their job properly, patients usually have to start a lifelong treatment known as dialysis, during which people are "connected" to a kind of "artificial kidney" that is responsible for filtering their blood outside the body.

When the kidneys are irreparably damaged, patients generally begin to dialyze. Dialysis consists of filtering the blood outside the body, using a device that works like an artificial kidney.

Glomerulonephritis

They are damage caused to the glomeruli, small structures contained in the renal nephrons, which are directly responsible for blood filtration.

Glomerulonephritis has to do with inflammation of these structures due to the use of drugs, infections of different types or congenital abnormalities.

References

  1. Fox, S. I., & Rompolski, K. (1996). Human physiology (p. 770). Dubuque, IA: Wm. C. Brown.
  2. Ganong, W. F. (1995). Review of medical physiology. Mcgraw-hill.
  3. Gartner, L. P., & Hiatt, J. L. (2012). Color atlas and text of histology. Lippincott Williams & Wilkins.
  4. Netter, F. H. (2014). Atlas of human anatomy, Professional Edition EBook: including NetterReference. com Access with full downloadable image Bank. Elsevier health sciences.
  5. Stephens, C. (2018, September 17). Kidney Health and Kidney Disease Basics. Healthline. Taken from healthline.com

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