Page 216 - Biology_F5

Comparative studies of natural groups of organisms

Dissection of mouse or rat 3.76). Pin it down on the tray through
A mouse or rat is a typical vertebrate the fore and hind limbs, make sure that
animal whose many aspects of structural the pins face outwards.
organisation are similar to those of
other mammals, including human being.
Moreover, mice or rats are also important
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research tool, for modeling human disease
progression and development in the Pinned limb
laboratory. They have also helped to speed
up the progress of research and enabled
the development of important new drugs.
Therefore, by examining the physiology,
anatomy and metabolism of a mouse or rat, Point to
scientists can gain a valuable insight into start a cut
how human system functions. Despite the
differences in their body size and appearance,
Mice/rats share a distinct genetic similarity Figure 3.76: Positioning the mouse or rat
for dissection
to humans; and their ability to reproduce
and mature quickly make them efficient (d) Lift the skin in the mid-ventral line
and economical candidate mammals for using forceps, and cut to make a small
scientific studies. slit (Figure 3.77). Cut forward to the
level of the lower lip and backwards
The purpose of conducting rat or mouse
dissection is to explore and study the around the penis and between the
internal organs and systems of the basic scrotal for a male specimen while for
mammalian anatomy. the female cut the skin backward as
far as the anus, passing either side of
General procedure of dissection of a urinary and genital apertures.
mouse or rat
Task 3.18
Watch videos or simulations on
dissection of a rat or mouse to display
the digestive or urinogenital systems.

(a) Put on a pair of gloves.
(b) Place a live male or female mouse
or rat in a container with a lid and
anaesthetize it using chloroform soaked Penis
in a small roll of cotton wool for five Scrotal sac
minutes.

(c) Lay the mouse or rat on the dissecting
tray or dish, with the ventral side
(abdomen) facing upwards (Figure Figure 3.77: Opening the body cavity of an
anaesthized mouse or rat

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