Norfolk

What kidneys normally do.

Kidneys do a lot.

Kidneys are vital organs (before dialysis and transplantation were around people died when their kidneys failed).

This page will introduce you to what normally working kidneys do.

This will reveal what is not done when the kidneys don't work.

And this in turn will explain what therapies we have to start, to do the jobs the kidneys can no longer do.

Kidneys have two roles:

A filtering role and a hormonal role.

Blue blood leaving the kidney filtered and clean.

The filtered stuff , the yellow urine, made of waste from blood (toxins and water) passing down to bladder.

The filtering role cleans the blood. Blood is always being passed into the kidneys through big blood vessels. All the stuff in the blood that is not wanted by the body, the "toxins", are filtered out by the kidneys and passed down tubes that lead to the bladder as urine. The toxins  (waste products) come from the normal food and drink we take in, and from the normal metabolism of the body. Filtered out with these toxins is any excess water that the body does not need.

So when the filtering role of the kidneys is failing the body will accumulate toxins (which can be poisonous and make you ill) and water which can saturate your body tissue ("water retention" or "oedema"). Oedema is commonly seen in the ankles and calves to begin with. Oedema can put a strain on your cardiovascular system (heart and blood vessels) because they are having to deal with so much water in the body.

When the kidneys are still working a bit (usually above 10% function) the doctors can treat the condition of kidneys not filtering very well with medication.

When the kidneys can only work less than about 10%, kidney failure can not be adequately treated with medication alone and renal replacement therapy is needed (dialysis or renal transplantation).

The hormonal role:

Kidneys produce substances (chemicals, hormones)  that stimulate other things in the body. These jobs of the kidneys play an important part in:

• Maintaining good blood pressure.
   

• Maintaining the right level of calcium in the body that keeps our bones healthy.
   

• Stimulating the production of our red blood cells. These cells carry oxygen around our body that enables us to have energy.
   

• Maintaining the right acid base balance in our bodies (the pH value). This balance is important because chemical reactions of the body do not react normally if the blood is too acidic or too alkaline.
   

• ... and the kidneys do other things...

So when the kidneys start to fail, the things mentioned above start to go wrong. These things can be treated by medication. This treatment by medication can be vitally important (life saving).

Links:

From the UK National Kidney Federation

From the Patient Kidney Guide

Medication: Medline Plus

From the UK National Kidney Federation

Find in much more detail about what normally working kidneys do from the links below:

Patient kidney guide - what kidneys do

Kimball's biology pages - The kidney

How your kidneys work - helpful animation of the filtering process