Renal Function Patho: Getting to Know Your Kidneys

Renal Failure Represents Lack Of Success And Ailments

Renal failure – an exam favorite and one of nursing students’ worst nightmare. If renal failure is making you anxious, let make it stupidly simple for you.

But first, let’s go to the basics – kidney function and location.

Whenever you hear the word “kidneys” there should be a light bulb inside your head that immediately triggers you to think about the fundamental pathophysiology happening inside those two bean-shaped structures inside your body. Let’s break it down effortlessly.

The Washer Machines

As previously stated, the kidneys look like two beans which are connected to the aorta and have renal arteries. Now, think of your kidneys as washer machines. Never mind the glomerular filtration rates or nephrotic syndrome or those complicated terms that you’ve acquired from reading your nursing books. All you have to think about at this moment is how your kidneys are washer machines in your body.

The primary function of your washer machines is to wash (filter) your blood, making sure it’s clean before it goes into the different parts of the body. As clean blood is being distributed to the entire system, dirty blood becomes urine and is eliminated down the ureters to the bladder and finally, to the potty.

From the wise words of Mike’s instructor: “Into the potty and not the body.”

Get The HUC Out of Here

Basically, there are three main elements that kidneys filter and they go by the acronym: HUC. What does HUC stands for?

  • H – Hydrogen Ions
  • U – Urea
  • C – Creatinine

Hydrogen Ions

One word: very acidic. Hydrogen ions are the by-product of H2O (water) – two hydrogen and one oxygen atoms.

While the body utilizes oxygen, it needs to get rid of the hydrogen from the blood and into the potty. Why? Because if your washer machines are broken, hydrogen with not be properly filtered and will not be eliminated from the body. This will cause acid build-up that will lead to metabolic acidosis. Therefore:

  • Increased hydrogen = metabolic acidosis


How is urea created?

From the small intestines, specifically the duodenum, protein is broken down. Think of protein as a protein bar that comes in with a wrapper. The body absorbs the protein while the wrapper becomes ammonia. Ammonia goes into the liver and is broken down in the form of urea. Urea is then sent through the exit portals of the liver to the washer machines to be appropriately filtered and be excreted by the body.

If the washer machines are broken, there will be a build-up of urea (uric acid) and is evidenced by your blood urea nitrogen (BUN). Therefore:

  • Increased urea = increased BUN

Take note: When BUN is increased, it doesn’t automatically indicate renal failure. There is a high possibility that your client is just dehydrated. This happens when the person has been exposed to the scorching heat of the sun for quite some time; the person becomes hemo-concentrated which results to the very high BUN. You can remember that through “very burned BUNs.”

So you’re wondering what happens if BUN and creatinine are both elevated? Read on.


Creatinine is the by-product of muscle metabolism. This does not mean rhabdomyolysis or the rapid breakdown of your muscle. Having creatinine in the body only means that there is constant and healthy muscle tissue break down and the end-product is creatinine. When the washer machines are broken, creatinine level in the urine is low because it’s stranded inside the body.

Again, from the wise words of Mike’s instructor: “Into the body and not the potty.”

To answer what happens when both BUN and creatinine are elevated:

  • Increased BUN and creatinine = possible kidney failure

What are the stages of progression of kidney failure regarding acute renal failure? That will be discussed in our following video that’s mainly dedicated to the condition: acute renal failure.

See you in our next video!