This document describes the parts and proper use of a compound microscope. It begins by listing the learning objectives of being able to describe the microscope, identify its parts, and explain the functions. It then explains that the optical system contains three sets of lenses: the condenser which illuminates the slide, various objective lenses which enlarge the image, and the eyepiece which provides further magnification. Other parts like the arm, base, stage, and nosepiece are also outlined. Guidelines for safe handling and focusing the microscope are provided.

1. COMPOUND
MICROSCOPE
DR. SYED WAJAHAT HASIB
LECTURER (ANATOMY)
1

2. OBJECTIVES
• By the end of this 2-hour lab skills session, the 1st year MBBS student
should be able to:
• Describe the compound microscope
• Identify different parts of a compound microscope
• Describe the functions of different parts of a compound microscope
2

3. 3

4. COMPOUND MICROSCOPE
• Most commonly used microscope is the
conventional bright-field microscope
• It contains an optical system and
mechanisms to move and focus the
specimen
4

5. PARTS OF A COMPOUND
MICROSCOPE
5

6. • The optical system comprises of 3 sets
of lenses:
1. Condenser
2. Objective lenses
3. Eyepiece (oculars)
6

7. • The optical system comprises of 3 sets
of lenses:
1. Condenser - collects and focuses a cone of light
that illuminates the tissue slide on the stage
2. Objective lens - enlarge & project the
illuminated image of the object towards the
eyepiece
3. Eyepiece (oculars) - magnify this image another
10x and project it to the viewer
7

8. • Other parts include:
1. Arm - supports the tube and connects it to the
base
2. Light source - illuminates the specimen from
below (110 volts bulb)
3. Base - stabilizes the apparatus
8

9. 4. Tube - connects the eyepiece to the
objective lenses, adjusts up and down
5. Stage - plate upon which a slide
with a specimen can be mounted
6. Clips - hold the slide in place
9

10. 7. Nosepiece - revolving plate attaching
different objective lenses
8. Focus:
• Coarse focus - raises / lowers stage to bring
image into focus
• Fine adjustment - brings image into sharp focus
10

11. HANDLING PROTOCOL
• Handle the microscope JUST DON’T MISHANDLE IT
• Always make sure they are placed on flat surface
• Make sure all backpacks are cleared from the table before you work on
a microscope
• Carry with one hand on the Arm and one hand on the Base, hold close
to your body
• Don’t lower the tube blindly on slide, do under direct vision
• Don’t touch the specimen on slide
11

12. HOW TO FOCUS
• Start with the lowest power objective lens first
• Place slide on stage with specimen in the center
• Place the lens down as close to the specimen as possible without
touching it, while looking from the side
• Look with both eyes
12

13. • Widen the gap b/w the binocular eyepieces & while looking in the eye
piece start closing in slowly until the two eye pieces circles combine
into one circular field
• Focus upward with coarse adjustment knob while looking through the
eyepiece lens until the image is sharp
• Sharpen the image by fine adjustment knob
• Continue with subsequent objective lenses and fine focus each time
13

14. TASK
• A student wants to view cells under the compound microscope at a
total magnification of 400X. If the eyepiece is 10X, which of the
following objective lenses should be used?
A 4X
B 10X
C 40X
D 100X
How do we calculate
magnification?
Eyepiece X Objective lens =
Total magnification
Correct Answer = C
14