Kidney factsheet

Kidney factsheet

1. Where are the kidneys and how big are they?

The kidneys are two bean-shaped organs located on either side of the spine, just below the rib cage. They are about the size of your palm: 12 (10-14) cm long, 6 cm wide and 3 cm deep, and weigh about 150g.

Even though the kidney only accounts for 0.5% of the body’s weight on average, it receives more blood (20-25% of the cardiac output) than all other organs except the liver.

2. Can you feel your kidneys?

No. You are not normally able to feel your kidneys. If you can, they are usually pathological (abnormal). They have to enlarge at least 2x to be palpable.

3. What is the main function of the kidneys?

The main function of the kidneys is to filter waste products and excess water from the blood to produce urine.

4. What are the additional functions of the kidney?

The kidney has 7 functions.

Primary excretory functions (3) – functions involving the filtration of waste in the body include:

1. Fluid and electrolyte balance
2. Waste removal
3. Acid-base balance

Other metabolic functions (4) – besides filtering waste, the kidneys also help regulate the body’s:

4. Red cells and haemoglobin
5. Bone biochemistry
7. Blood pressure
8. Prostaglandins.

5. How do the kidneys work?

Each kidney contains 1 million tiny filters called called glomeruli, which act as tiny sieves in the filtration process.

Medical conditions - Kidney failure

Stretched out from end to end, the nephrons (that includes the glomeruli and tubules) are about 5 miles (8 kilometers) long.

6. What is Glomerular Filtration Rate (GFR)?

This is the amount of filtrate formed per minute by the glomeruli in the kidneys – it is a measure of kidney function because it shows us how much the kidneys are filtering and doing their job.

Normal human GFR is about 120 ml/min, or 7 litres per hour, or 180 litres per day.

7. What is an Acute Kidney Injury (AKI)?

An AKI is a condition in which the kidneys rapidly lose function (usually over hours or days), potentially leading to kidney failure if left untreated.

8. What is Chronic Kidney Disease (CKD)?

Chronic kidney disease (CKD) is a long-term condition where the kidneys do not work as well as they should, or are damaged in some way – potentially leading to kidney failure if left untreated.

Explaining Your Kidney Test Results: A Tool for Clinical Use - NIDDK

9. What are kidney infections and stones?

A kidney infection is called pyelonephritis. Most urinary tract infections (UTIs) are bladder infections (or cystitis).

Kidney stones, which are common, can form when there is an accumulation of certain substances in the urine, causing them to crystallise and form solid masses.

10. What is kidney cancer?

Kidney cancer includes cancers of the outer kidney (90%; cortex and medulla), inner kidney (5%; pelvis, drainage system) and the ureter (5%).

Summary

We have described 10 quick kidney facts. We hope you have found it helpful.

Other resource

https://www.youtube.com/watch?v=za78Uqroios

Last Reviewed on 22 May 2024

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