3. Introduction to the microscope
A microscope from the ancient Greek (Micro = small), and
(Scope = look or see) is an instrument used to see objects that are
too small to be seen by the naked eye.
Microscopes are used to
- observe the shape of bacteria, fungi, and parasites
- study the structure of cells and sub-cellular components..
The microscope is widely used in medicine and biology.
4. Types of microscope
various types of microscopes are available for use
in the microbiology laboratory :
1. Light (optical) microscopes.
Light microscopy involves the use of optical lenses
and light radiation
2. Electron microscopes.
5. Parts of Light compound microscope
The light microscope is sensitive parts
that must be handled carefully and
consists of :
6. 1. Eyepiece lenses : the lens
that sees through which, it is
located at the top of a small
cylinder.
* The strength of eyepiece
lenses zoom (10x).
7. 2. Body tube:
the cylinder part in a microscope ,
that carries in the highest eyepiece
lens.
8. 3. Revolving nosepiece:
a circular part that is
connected to the lower part
of the cylinder and is used to
change the position of
objective lenses.
9. 4. Objective lenses: a set of 3-4 disk-related lenses :
- short with a micro power zoom lens (4x),
- the medium-sized lens with centrist power (10x),
- a great lens with high power zoom (40x),
- there is also the oily lens that upsized force (100x), if using this lens is
used for a clearer view called (Oil immersion).
10. 5. Stage : it is the surface on
which we put the objects to
test and there is a small
aperture in the center that
allows the light to pass
through the slide.
11. 6. Condenser:
it is under the stage aperture,
its function is the collection
of light rays, where we can
control the focus of the light
directed to the slide by
moving it up and down.
12. 7. Diaphragm:
this part at the bottom
of the stage whereby we
can regulate the amount
of light entering the
object lens by slide.
13. 8. Coarse adjustment:
a big wheel on both sides of
the microscope is used to
organize the distance between
the stage and the object lens
to get a clear view.
14. 9. Fine adjustment:
is a small wheel that is
also on both sides of the
microscope and is used to
help see the sample more
clearly.
15. 10. Stage movement controls. 11. Arm: used to carry
the microscope and cylinder.
