One of the body’s systems is the Renal System. The parts involved in this system are the Kidneys, bladder, urethra, and ureters. The renal system’s primary function in the body is the elimination of excess substances and waste products in the blood which are carried out of the body along with Urine

The kidneys, which are sizeable bean-like shape organs, are responsible for removing Urea. Urea is a waste product that results from protein being broken down by your body. A kidney that has trouble carrying out its functions can cause a build-up of waste in the body, which can lead to a multitude of life-threatening conditions. 

To have a better understanding, here’s a simple overview of the renal system and a little bit more facts to keep you on top of things.

The Anatomy of the Renal System and How it works

As mentioned earlier, the renal system involves a lot of organs and muscles located in the abdomen. The kidneys are retroperitoneally situated inside the abdominal cavity, lying near the 12th thoracic and 3rd lumbar vertebrae. On top of the kidneys, lie the adrenal glands

Aside from removing waste products in the body and bloodstream, the kidneys are responsible for numerous vital processes required for a human body to function normally:

  • Balance Electrolytes in the body
  • Balances the fluids in the body
  • Activates Vitamin D which strengthens calcium absorption needed by the bones
  • Releases Erythropoietin, a hormone that stimulates the production of red blood cells
  • Plays an essential role in the Renin-Angiotensin-Aldosterone system which in turn is responsible for controlling blood pressure

The Kidneys

Inside your kidneys, contain the basic unit of the renal system called the Nephrons. These nephrons are responsible for filtering out waste and excess substances in your blood. If we were to split the nephron a little bit more, we will find integral structures namely: Renal artery, Renal vein, Glomerulus, and the Tubule. The renal arteries run through the glomerulus which filters the blood of waste products. The tubules are what pulls out the wastes and return the vital substances to your blood. The end of waste product becomes urine. 

The renal arteries in the kidneys are responsible for blood flow and carrying the unfiltered blood towards your kidneys. When the filtration process is done, the filtered blood makes its way to the body via the renal veins of your kidneys. 

The Excretion Process

The tubes that are connected down to the kidneys are called the Ureters. The ureters are ducts by which Urine from the kidney passes. The ureter leads to the bladder. The waste products, along with extra water from the body, goes down the bladder where it is stored. When the bladder is full, some people often feel some pressure below the peritoneal area. The bladder is full of smooth muscles, which, in turn, controls the release of urine. 

The body excretes the urine through the Urethra. In males, the urethra is much more complicated as it has a function shared with the reproductive system. Although we all can hold out our bladders, it isn’t advisable as it can severely damage the renal system. Some people who have disorders in the renal system or those who have weak bladders often have problems with holding their Urine. 

Diseases and Conditions of the Renal System

Although all the systems in the body all have crucial functions, the Renal system is where you should not have a problem with. Since the renal system is in charge of getting out waste of your body, issues within it can lead to other diseases and conditions of the other systems.

People who have diseases such as ESRD or End-Stage Renal Disease, often have to rely on Dialysis machines to help them filter out waste in their blood. Dialysis is expensive and is very tiring to a patient. Here are some more diseases and their simple pathophysiologies.

Kidney Failure – A partial or total loss of its functions. Can be classified as Acute or Chronic. Once there is kidney failure, nitrogen, potassium, sulfates, urea, and other waste products are left behind and can accumulate in the blood. Kidney failure can have complications such as Heart Failure and Pulmonary Congestion

Pathophysiology of Chronic Kidney Disease (CKD)

Nephrolithiasis – Minerals can form in your kidneys. These small minerals then become crystals or renal calculi, which can damage the ureter and other structures in your renal system. Urinating can also become painful when you have kidney stones.

Interesting Facts about your Renal System

  • Just like other organs in the body, the kidneys know how to compensate for each other. If one kidney begins to deteriorate, the other healthy kidney can grow to almost half its size to handle the filtration tasks left behind by the unhealthy kidney. This is the reason why most people can live with just one kidney.
  • The human bladder can usually hold almost 400ml of Urine.
  • Believe it or not, Urine is non-toxic and is actually sterile unless the person has any urinary tract infections.
  • Drinking excessive amounts of water can cause Hyponatremia and other fluid imbalances.
  • It’s normal for your kidneys to be asymmetrical


The Renal System is mostly made up of organs and muscles that are responsible for flushing out waste products out of our body. The kidney is the main organ which works by filtering out the wastes out of our blood. The wastes travel through the ureter to the bladder, and then finally, to the urethra as urine. 

It’s very important for us to keep our renal system healthy. An impaired renal system can cause severe diseases and conditions such as ESRD and Diabetic Kidney Disease. Being adequately hydrated and having lifestyle modifications can greatly help you maintain a healthy renal system.