The kidneys perform an irreplaceable function in the human body: They filter the waste products of our metabolism. This means that they remove the excess molecules from the blood, serving as a natural filter. They then send these wastes to the bladder. The whole process needs to run smoothly in order for our bodies to stay as healthy as possible.
Glomerular filtration is the name of the process that your kidneys go through in order to eliminate the bodily wastes. The glomerular filtration rate, also known as GFR, might be tested by your doctor. This rate determines just how well your kidneys are working.
What Are Glomeruli?
Each kidney has certain structures that help with that filtration. Tiny blood vessels in the kidneys, known as glomerulus, are known as “glomeruli” when they are taken as a whole. These glomeruli are inside a tiny capsule in the kidney known as a Bowman’s Capsule.
Blood passes into the glomeruli. The walls of these vessels are leaky, and that’s good – that’s how it filters out the parts of the blood that need to be taken away as waste. The blood that remains is sent back into the body. The parts that get filtered out are dumped into the Bowman’s Capsule. From that point, it goes into the bladder.
This process is extremely efficient – so much so that the healthy kidneys can filter all the blood in the body within a five minute period. As you get older it might take a bit longer.
How Does Glomerular Filtration Work?
Glomeruler filtration happens when the fluid in the blood is drained through those capillaries, or vessels, and the waste is separated. The process starts when the blood is pushed under high pressure into those vessels. It goes into the Bowman’s capsule, as mentioned earlier, and is then filtered by the glomeruli. These blood components always include nitrogenous waste, water, and nutrients. There might be other things in the blood as well, depending upon your health.
These things are transferred from the glomeruli to the bladder. This process results in what is known as the glomerular filtration rate, which reflects, in short, how quickly does the body move through the process, and how long does it take for the blood to filter properly in order to send waste to the bladder.
What Is Glomerular Filtration Rate (GFR)?
The glomerular filtration rate determines just how fast the kidneys filter from the glomerulus into the Bowman’s capsule. This is determined by combining the results of a blood creatinine test, your body size, your gender, and your age. This formula results in the GFR. A normal GFR means all is well, but an abnormal reading can tell the doctor if your kidneys are failing. You might find that you have very mild renal problems, or the test can show that you are actually going into kidney failure.
There are two forces that drive the glomerular filtration rate. The first is the hydrostatic pressure, which is the pressure exerted on the fluid as it is pushed through the glomeruli. This blood pressure forces the blood through the process. The more pressure, the faster the process. The second force is the oncotic pressure, which is exerted by proteins in the glomeruli. The protein tries to hold onto the water, which means it makes it tougher for the kidneys to filter it away. There should be no proteins in the Bowman’s capsule; if there are proteins there, that indicates a medical issue with your kidneys.
What Does This All Mean When It Comes to the GFR Values?
The glomerular filtration rate can help determine the stage of kidney disease you might be in. For a normal glomerular filtration rate, you should see a number of 90 or above on the test, as well as no protein found in the urine. Very mild kidney damage might be seen if you have an underlying medical condition, even if your number is 90 or above, so further testing might be indicated.
Mild kidney failure is indicated by a GFR of 60 to 89; moderate is at 30 to 59; severe is at 15 to 29. You are in kidney failure if you are at less than 15 on the glomerular filtration rate test. This means that you might need dialysis or some other form of medical intervention in order to stay healthy and alive.
However, keep in mind that your age is a key component in determining kidney failure; those who are elderly might have lower numbers than those who are younger, but their kidney function might be just fine. Remember, it is a matter of speaking to your doctor and running more than the glomerular filtration rate test to determine your true level of kidney function.