The Kidneys
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© Boardworks Ltd 2009
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© Boardworks Ltd 2009
Waste removal
Several organs are important in removing waste from the body.
The lungs remove carbon dioxide.
The skin provides a surface for small amounts of water and salt to move out of the body.
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The liver converts excess protein into urea.
The kidneys remove unwanted substances such as urea, excess water and salt.
© Boardworks Ltd 2009
What is urea?
Excess amino acids in the body are broken down by the liver, producing a waste substance called urea.
This process is important because it converts toxic ammonia to urea, which is done using carbon dioxide.
Once formed, urea is transported by the circulatory system to the kidneys.
The kidneys filter the blood, removing urea and excess water and salt, which forms urine. Urine is stored in the bladder before being excreted from the body.
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What are the different parts of a kidney?
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How does the kidney work?
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Stages in the nephron
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Controlling water content
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© Boardworks Ltd 2009
Regulating water content
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© Boardworks Ltd 2009
Analysing urine
Changes in the colour, clarity, pH and the presence of certain substances in urine can help doctors diagnose medical conditions: Protein or red blood cells in urine can indicate kidney damage or disease, as these substances would not normally filter through the glomerulus.
Glucose in urine is often an indication of diabetes. A person with diabetes will have a high level of glucose in the blood.
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© Boardworks Ltd 2009
Which sample?
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© Boardworks Ltd 2009
What happens if the kidneys fail?
Humans can survive with just one functioning kidney. If both kidneys become diseased or damaged, it can be fatal.
Kidney failure can occur due to infection, diabetes, long-term high blood pressure or damage in an
© Boardworks Ltd 2009
2 of 27
© Boardworks Ltd 2009
Waste removal
Several organs are important in removing waste from the body.
The lungs remove carbon dioxide.
The skin provides a surface for small amounts of water and salt to move out of the body.
3 of 27
The liver converts excess protein into urea.
The kidneys remove unwanted substances such as urea, excess water and salt.
© Boardworks Ltd 2009
What is urea?
Excess amino acids in the body are broken down by the liver, producing a waste substance called urea.
This process is important because it converts toxic ammonia to urea, which is done using carbon dioxide.
Once formed, urea is transported by the circulatory system to the kidneys.
The kidneys filter the blood, removing urea and excess water and salt, which forms urine. Urine is stored in the bladder before being excreted from the body.
4 of 27
© Boardworks Ltd 2009
What are the different parts of a kidney?
5 of 27
© Boardworks Ltd 2009
How does the kidney work?
6 of 27
© Boardworks Ltd 2009
Stages in the nephron
7 of 27
© Boardworks Ltd 2009
Controlling water content
8 of 27
© Boardworks Ltd 2009
Regulating water content
9 of 27
© Boardworks Ltd 2009
Analysing urine
Changes in the colour, clarity, pH and the presence of certain substances in urine can help doctors diagnose medical conditions: Protein or red blood cells in urine can indicate kidney damage or disease, as these substances would not normally filter through the glomerulus.
Glucose in urine is often an indication of diabetes. A person with diabetes will have a high level of glucose in the blood.
10 of 27
© Boardworks Ltd 2009
Which sample?
11 of 27
© Boardworks Ltd 2009
12 of 27
© Boardworks Ltd 2009
What happens if the kidneys fail?
Humans can survive with just one functioning kidney. If both kidneys become diseased or damaged, it can be fatal.
Kidney failure can occur due to infection, diabetes, long-term high blood pressure or damage in an