Lecture 1 Microscopy Flashcards
What is histology?
Study of tissue, structure of tissues
True or False: Magnification does equal resolution
False, it does not
Who help propelled microscopes?
Carl zeiss
______ is used for observation of intact specimens at relatively low magnification.
Stereomicroscope
______ is used for histological sections and cells
Compound light microscope Upright and Inverted.
______ is used to view subcellular details
Electron microscope Transmission and scanning.
A _______ is an optical instrument having a magnifying lens or a combination of lenses for inspecting objects too small
microscope
What is the visible spectrum range?
400-700nm
What are the 3 basic dimensions of light?
Intensity, frequency, polarization
______ (amplitude) which is related to the perception of ______
Intensity, brightness
______ (wavelength), perceived as ______
Frequency. colour
______ (angle of vibration) which is not or weakly perceptible to humans
Polarization
______ is the minimal distance of two points that can be distinguished.
Resolution (airy discs)
______ is an estimate of how much light from the sample is collected by the objective
numerical aperture
True or False: More light = higher resolution
True
What is the equation for numerical aperture?
NA = n sin α n = refractive index α = angle of incident illumination
True or False: Numerical aperture determines resolution
True
______ is defined by magnification by the objective x the magnification by eyepiece
Magnification
True or False: maximum magnification does not mean maximum resolution!
True
What is wrong with this image?
Condenser not properly focused -uneven illumination
What are the 6 types of contrasting techniques?
Brightfield
Darkfield
Phase Contrast
Polarization Contrast
Differential Interference Contrast (DIC)
Fluorescence
What is brightfield microscopy used for?
specimens that can be contrasted via dyes.
True or False: Only light that is scattered by structures in the sample enters the objective
True
What is darkfield microscopy used for?
People use it a lot to look at Diatoms and other unstained/ colourless specimens
True or False: Phase contrast is invasive
False, not invasive, cells can be alive
What is polarization contrast used for?
used to look at materials with birefringent properties (ie, collagen)
______ makes better use of the numerical aperture of the system and allows the microscope to achieve excellent resolution.
DIC
How do you prepare a tissue sample?
Formalin fixation, paraffin embedding (fixation, dehydration w/ alcohol to 100%, clearing -xylene, infiltration - melted paraffin - embedding- placed in small mold to harden)
______ is used in medical conditions because of faster turnover time
Cryosectioning
______ samples are critically pointed dried and coated with a conductive material (gold).
SEM
______ is stained with heavy metals and the area is very small
TEM
