his1 Flashcards
(26 cards)
What are the lenses for the optical component ?
Condenser
Objective
Eyepiece
what is the resolving power?
the smallest distance between two structures at which they can be seen as separate objects
What is the function of condenser ?
r focusing light on the object
to be studied
What is the function of objective lens?
enlarging and projecting the
image of the object toward the observer
what is the function of eyepiece ?
Increasing the image magnification and projecting
it onto the viewer’s eye
what is the The critical factor in obtaining a crisp, detailed image with a light microscope ?
the resolving power
what is The maximal resolving power of the
light microscope ?
0.2 μm مايكرو ميتر
How much can you enlarge the images?
1000-1500 times
WHAT VIRTUAL MICROSCOPY USED FOR?
STUDY OF BRIGHT FIELD MICROSCOPIC preparations
how we can use the fluorescent compounds wITH affinity for specific cell macromolecules ?
as fluorescent stains
what is the fluorescence ?
irradiate cellular substances with light of a proper wavelength they emit light with a longer wavelength
in fluorescence
microscopy, tissue sections are usually irradiated with ?
(UV) light and visible portion of
the spectrum.
how can we study the Unstained cells and tissue sections?
by using the modified
light microscopes LIKE Phase-Contrast
why . Cellular detail is normally difficult to see
in unstained tissues ?
because all parts of the specimen have
roughly similar optical densities
what Phase-contrast microscopy based on ?
light changes its speed when passing through cellular and extracellular structures with different refractive indices
Why is light at different speeds in phase contrast micro?
to appear lighter or darker in relation to each other.in the structures
what differential interference contrast microscopy with Nomarski optics produce
an image of living cells with a more apparent three-dimensional (3D
Why do we use Confocal Microscopy ?
to Achieves high resolution and sharp focus
why we can get high resolution and sharp focus with using confocal microscopy
Because the final incident light is a small point of high intensity light, often from a lase
Because there is a pinhole plate in front of the image detector.
What is the function of polarizing microscopy
allows the recognition of stained or
unstained structures made of highly organized subunits.
tissue structures containing oriented macromolecules
are located between the two polarizing filters, their repetitive structure rotates the axis of the light emerging from the
polarizer and they appear as bright structures against a dark
background
فهم
what is the birefringence ?
The ability to rotate the direction
of vibration of polarized light
example of birefringence ?
cellulose collagen micro-tubules actin filaments
EXAMPLE FOR FLUORESCENT STAINS ?
ACRIDINE ORANGE(DNA /RNA) AND DAPI stain specifically bind DNA and
are used to stain cell nuclei
