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Biology for Advanced Level Secondary Schools
and face during and after dissection. Questions
Hands should be thoroughly washed 1. Describe the digestive system of the
with soap or disinfectant immediately displayed cockroach.
after conducting a dissection practical 2. Compare the structures of the
session. dissected cockroach with those
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4. All other safety laboratory rules depicted in Figure 3.59.
should be observed; the teacher or 3. Explain how the central location
laboratory technician should guide of a gizzard helps the organism in
the students. digestion.
4. How does the crop differ from the
Task 3.15 digestive caeca?
Search from internet sources and watch
video or simulation showing dissection Note:
of a cockroach.
1. The diagrams should be well drawn,
large enough, generally neat and
Activity 3.13: Dissection of a accurate.
cockroach to display the digestive
system 2. The caption should be well indicated;
when written on top of the diagram it
Materials should be capitalised and underlined,
Fresh male or female cockroach, while when written below the diagram,
dissection kit, chloroform, dissecting the first letter should be upper case and
tray or dish with wax intact, source of should not be underlined.
heat, and water
3. Label lines should be indicated in
Procedure pencil; should be straight without
(a) Collect a fresh male or female arrows; and should not cross each
cockroach. other.
(b) Prepare a dissecting tray or board 4. Labelling words should be on the
and chloroform for anaesthetising required parts and written using blue
the specimen.
or black ink.
(c) Dissect the cockroach in a usual
way; deflect the gut to your right 5. The magnification of the diagram
hand side, to fully display the should correspond to the real
specimen.
digestive system.
Form Five Student’s Book
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