Microscopy Flashcards
Who produced the first operational compound microscope with a magnification of 30x
Janssens
Who described cork and other cells and introduced the term cell
Hooke
What did Bichat do?
recognized 21 kinds of membranes (tissues) but did not use microscope
who formed the cell theory
Mirbel, Turpin, Virchow
Who came up with the free cell formation theory
Schleiden
what is the free cell formation theory
cell is essential unit of the living organism (idea that cells arise by budding from the nucleus)
Define refraction of light
bending of light waves
what is the equation for refractive index
velocity of light/velocity of light inside transmitting medium
what does the degree of bending depend on in optics
Refractive Index
angle at which light strikes surface
what is refractive power
measure of how much a lens bends light waves. measures in diopters
define focal point
point through which all parallel rays of light will pass after passing through each part of the lens
define focal length
distance from the center of the lens to the focal point
name characteristics of real image
object is outside focal point
real image is inverted
real image can be projected onto a screen
real image differs in size from the object
name characteristics of virtual image
object is placed inside the focal point
virtual image is not inverted
virtual image cannot be projected onto a screen
virtual image can be magnified
define resolution
ability of a microscope to distinguish 2 small points as separate points
what are the components of a compound optical (light) microscope
light source condenser stage objective lens ocular lens
what are the pros of compound optical (light) microscopes
ability to magnify
ability to resolve structural detail
what are the cons of compound optical (light) microscopes
specimen must be thin
relatively little contrast in the unstained specimen
what do phase contrast microscopes do
converts phase shifts in light passing through a transparent specimen to brightness changes in the image
what is phase contrast microscopes particular useful for examining
unstained cells and tissues
living cells
(used more for research than medical application)
what do fluorescence microscopes do
detects molecules that emit light of wavelengths in the visible range when exposed to a UV light source
give examples of how fluorescence microscopes are used
detection of antigens or antibodies in immunochemical staining procedures
detection of fluorescent tracers injected into animals or cells
what microscope allows for the reconstruction of 3D images
confocal scanning microscope
name some advantages of confocal scanning microscopes
very thin optical images of the specimen are created
out of focus images are subtracted from the image by the computer program
computer can make 3D reconstructions of the specimen by stacking individual images
what are the components of transmission electron microscopes
cathode heated tungsten filament anode series of electromagnets: condenser lens, objective lens, projection lens specimen holder viewing screen and photographic film
