A system of accurately ground
lenses arranged to give sharp,
clear, magnified images of
minute objects
M I C R O S C O P E
The technology of making very
small things visible to the
naked eye
M I C R O S C O P Y
M I C R O S C O P Y
Zacharias Jannsen microscope 1608
the process of enlarging something
only in appearance
M A G N I F I C A T I O N
related to scaling up visuals or
images to be able to see more detail
M A G N I F I C A T I O N
MAGNIFICATION
100
40
10
4
the ability of the lenses to distinguish
fine detail and structure
R E S O L V I N G P O W E R
ability to distinguish two points a
specified distance apart
R E S O L V I N G P O W E R
Principle:
- when two substances have a
different index of refraction, the
light will bend as it passes from
one material to another
R E F R A C T I V E I N D E X
Has one lens, similar to a
magnifying glass
S I M P L E M I C R O S C O P E
Leeuwenhoek’s simple
microscopes magnify images
from 100X to 300X
S I M P L E M I C R O S C O P E
T Y P E S O F
MICROSCOPY
LIGHT MICROSCOPY
A. BRIGHTFIELD
B. DARKFIELD
C.PHASE-CONTRAST
D. FLUORESENCE
E. DIFFERENTIAL INTERFERENCE CONTRAST
F. INVERTED
The microscope uses visible light to
observe specimen
L I G H T M I C R O S C O P Y
- Specimen appears
against a bright
background - Use: various stained
specimens
B R I G H T F I E L D
- Special condenser with
opaque disk. Light enters
the objective lens - Use: for microorganisms
which cannot be stained
D A R K F I E L D
- Uses condenser with annular
diaphragm which allows direct
light to pass through the
condenser - Use: detailed examination of
internal structures; does not
require staining
P H A S E - C O N T R A S T
- Uses a UV or near-UV
source of illumination - Use: observation of
natural fluorescence and
immunofluorescence
F L U O R E S E N C E
- Uses different refractive
indexes to produce image - Use: provides 3D images
of sample
DIFFERENTIAL INTERFERENCE CONTRAST
- Light source and
condenser is on top,
above the stage - Use: observation of living
cells under more natural
conditions
I N V E R T E D
Microscope uses beam of electrons
instead of light
E L E C T R O N M I C R O S C O P Y
Offers much greater resolving power
E L E C T R O N M I C R O S C O P Y
E L E C T R O N M I C R O S C O P Y
SEM, TEM, STM
Electrons are reflected from
the specimen; magnifies
1,000 to 10,000X
- Use: study of surface
features of cells and viruses
SCANNING ELECTRON (SEM)
Electrons pass through the
specimen; magnifies 10,000
to 100,000X
- Use: examination of viruses
or internal ultrastructure in
thin sections of cells
TRANSMISSION ELECTRON (TEM)
