KEY STAGE 5 CHEMISTRY I LESSON PLAN 1 – KIDNEY STONE ANALYSIS RESOURCE SHEET 1.1 What are kidney stones? Kidney stones are also known as renal calculi. They are formed when minerals crystallise out of urine either in the kidneys or in the tubes which carry urine from the kidneys to the bladder (these tubes are called ureters). Some stones are small enough to pass through the urinary tract without problems, but when they get to 3mm or larger in diameter, they can cause severe difﬁculties for the patient. Kidney stones the size of grapefruits have been reported, but the majority are somewhat smaller! The pain caused by a kidney stone is extremely intense. If possible, the patient is encouraged to pass the stone naturally, and in some cases, the stone will be broken up by ultrasound to facilitate the process. Surgery is considered a last resort, unless there are extenuating circumstances (e.g. if the patient has a history of kidney problems). The majority of kidney stones are composed mainly of calcium oxalate, but a range of other chemical substances may be present in the stone. The exact composition of a stone may give useful information about a patient’s health. For example, a magnesium ammonium phosphate stone is a clear indicator of a urinary tract infection. In order to analyse a stone, the patient will have to retain it as it is passed out. The usual method of doing this is to urinate through a sieve. Once the stone has been collected, its appearance is noted as this is often a good ﬁrst indicator of its composition. More detail can then be obtained from analysis using a range of chemical tests. For convenience, the NHS uses testing kits which have the required reagents pre-made in the correct concentrations, and a biomedical scientist working in the clinical chemistry or biochemistry department will carry out the appropriate tests to identify the composition of the stone. Doctors can then use the results to identify any underlying health issues which may be contributing to the patient’s problems.

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Page 1: Key Stage 5 ChemiStry i LeSSon PLan 1 – Kidney …wonderstruck.co.uk/resources-and-downloads/RS1.1-What-are-Kidney... · Key Stage 5 ChemiStry i LeSSon PLan 1 – Kidney Stone anaLySiS

Key Stage 5 ChemiStry i LeSSon PLan 1 – Kidney Stone anaLySiS reSourCe Sheet 1.1

What are kidney stones?

Kidney stones are also known as renal calculi. They are formed when minerals crystallise out of urine either in the kidneys or in the tubes which carry urine from the kidneys to the bladder (these tubes are called ureters). Some stones are small enough to pass through the urinary tract without problems, but when they get to 3mm or larger in diameter, they can cause severe difficulties for the patient. Kidney stones the size of grapefruits have been reported, but the majority are somewhat smaller!

The pain caused by a kidney stone is extremely intense. If possible, the patient is encouraged to pass the stone naturally, and in some cases, the stone will be broken up by ultrasound to facilitate the process. Surgery is considered a last resort, unless there are extenuating circumstances (e.g. if the patient has a history of kidney problems).

The majority of kidney stones are composed mainly of calcium oxalate, but a range of other chemical substances may be present in the stone. The exact composition of a stone may give useful information about a patient’s health. For example, a magnesium ammonium phosphate stone is a clear indicator of a urinary tract infection.

In order to analyse a stone, the patient will have to retain it as it is passed out. The usual method of doing this is to urinate through a sieve.

Once the stone has been collected, its appearance is noted as this is often a good first indicator of its composition. More detail can then be obtained from analysis using a range of chemical tests. For convenience, the NHS uses testing kits which have the required reagents pre-made in the correct concentrations, and a biomedical scientist working in the clinical chemistry or biochemistry department will carry out the appropriate tests to identify the composition of the stone. Doctors can then use the results to identify any underlying health issues which may be contributing to the patient’s problems.