On your dissection tray you will find:
§
one cow brain
§
scalpel
§
probe
§
holding pins
You must take notes throughout the dissection, to document both your
procedure and your findings. These should be in point form (use a chart if that
works better for you), and must be clear.
Each notation should have two parts:
1)
what you did (and where, and how)
2)
what you observed
For example:
|
|
What we did |
Where (exactly) |
What we observed |
Comments |
|
Procedure 6 |
Sliced down (vertically) through
the cerebellum |
4cm from where it joins the midbrain |
Looks like a walnut, with many folds. Yellow-grey color outlined in
white. Texture is firmer than the
cerebral cortex. |
White stuff is probably myelin.
|
|
Proceedure 7 |
removed brain stem and sliced lengthwise |
in the middle |
irregular shapes, pons,
medulla oblongata, midbrain.
Texture very firm, fatty deposits on the outside |
brainstem is much firmer than the main brain. Texture is stringy and easy to cut. Easy to see the various areas. |
…and so on. Make sure you share
jobs throughout the dissection; it shouldn’t always be the same person taking
notes, unless you’re working alone.
Drawings are a great tool for recording your observations; your finished
lab should contain at least three drawings, labelled with your
observations.
The instructions for this lab are pretty
simple and, you have considerable freedom in deciding how you will
proceed. There are a few important
things to remember:
§ You must proceed
gently—brains are fragile—and with caution.
§ Be careful with
scalpels and probes. Wear gloves at all times.
§ Conduct yourself
in a manner appropriate to the laboratory.
Procedure
1.
Observe the intact brain.
Record your observations and comments.
2.
Make an incision, or gently manipulate the brain to reveal new
views. Record your procedure and your
subsequent observations. Don’t forget
drawings.
3.
Continue your dissection. Don’t
forget to use the microscopes to aid in your observations.
4.
15 minutes from the conclusion of the class, clean
up your station. Dispose of biological
material and gloves in the receptacle provided, and wash your hands with soap. Do
not leave the lab without washing your hands.
Your finished
lab will consist of your notes and observations, and your drawings. Each
drawing must be labelled with the name of the student who drew it.
Some suggestions:
Target what interests you. A dissection is a fascinating thing, and you
are encouraged to proceed in the direction that interests you the most. See what you can find out.
Plan your dissection. If you just hack and slash randomly you
won’t have a chance to observe very much.
Likewise, some cuts will preclude others, so think ahead.
Adjust your plan based on
your observations. If your plan
isn’t showing you much of interest, try something different. If you see something really cool,
investigate further.
Most importantly…
Figure things out! Form hypotheses, take a guess--learn
something! Don’t worry if you’re not sure what you’re seeing; make your
observations, ask others about theirs, work on your conclusions later.