Biomedical Engineering Reference
In-Depth Information
Fig. 6.1
Earthworm,
Eisenia fetida
(
a
), and its nervous system (
b
)
Vegetable Mould through the Action of Worms, with Observations on their Habits
in
1881 as his last study. In this topic, he mentioned the intelligence of this small ani-
mal, partly concerning their learning and memory abilities.
On the other hand, many people have their fi rst experience performing biological
experiments using the earthworm because of the frequent use of this animal as a
specimen for physiological experiments during undergraduate studies. The earth-
worm has three giant nerve fi bers: one medial giant fi ber (MGF) and a pair of lateral
giant fi bers (LGFs, Fig.
6.1
) (Edwards and Loftly
1972
; Mill
1982
). We can measure
the propagation of action potentials along these giant fi bers using a simple nerve box
as a source of extracellular potential, and this simple experimental setup has been
used for elementary experiments for newcomers to the Department of Biology.
