JSSS
Teacher Support Material
Investigating the structure of the kidney
1A6 Excretion
Materials
Lamb’s kidneys, dissection instruments, dissection boards, newspaper, plastic bag, disposable
gloves (optional), paper and pencil, hot soapy solution, disinfectant
Note

Lamb’s kidneys available in butchers or supermarket, approx. 20c. Lamb’s kidneys are
still used in cooking, and though smaller they still closely resemble human kidneys.

If concern about use of sharp dissection instruments is a barrier to student dissection,
blunt dissection (used by surgeons when cutting soft tissue) of kidney tissue is quite easy
to carry out using paper scissors, approx. 99c from newsagents. The scissors are opened
out and used to cut through the tissue like a scalpel.

If using metal scalpels, disposable blades should be used only once – being mounted and
removed by the teacher. Plastic scalpel blade removers are available from scientific
suppliers, the advantage of these is that the blade remains within, and can be disposed of
in, the remover.

If dissection boards are not available, dissection can be carried out on newspaper.

Gloves are not necessary but may tempt the more “squeamish” to investigate.
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JSSS
Teacher Support Material
Advance preparation

Lamb’s kidneys bought in quantities can be kept in a freezer and defrosted overnight.

It is advisable to inform the students beforehand that dissection will take place.

Students should be informed of the basics of dissection – external observation and
description followed by dissection, internal observation and description.
Dissection

Students should be encouraged to try to match the structures they see before with the
diagrams or photographs in their text book.

Students should make a simple sketch of what they see (i) outside (ii) inside the kidney.

Students should be encouraged to use the sense of touch and smell as well as sight – can
they connect the smell of urea from the kidney with what they know of its function.

Students can be prompted to think about the layer of fat (if present), the lack of blood, the
lack of muscle present, the smell of urea (ammonia).
Disposal
Used lamb’s kidney can be wrapped in newspaper along with the used gloves, sealed in a plastic
bag and disposed of with the day’s laboratory refuse.
Disinfection
Dissection instruments should be carefully washed with hot soapy water, dipped in disinfectant
solution and dried well before storage. Removed scalpel blades in their holders should be
carefully disposed of.
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