Microscopy

Question 1

eyepiece or ocular lens

Answer 1

moves to focus the image onto the eye

Question 2

objective lens

Answer 2

provides image magnification and image resolution

Question 3

lens

Answer 3

magnifies light from the objective lens

Question 4

nosepiece

Answer 4

revolves to move the desired lens into position

Question 5

diaphragm lever

Answer 5

controls the amount of light reaching the object

Question 6

condenser

Answer 6

concentrates light on the tissue section, needs to be focused on the same plane as the tissue section

Question 7

compound microscope

Answer 7

combination of two simple microscopes or magnifying lens systems

Question 8

resolving power

Answer 8

the least distance between 2 objects that are still seen as two rather than one. Usually 0.2um minimum distance apart to be resolved

Question 9

achromatic objectives

Answer 9

corrected for 2 colors, red and blue, most lab microscopes

Question 10

apochromatic lens

Answer 10

corrected for 3 colors

Question 11

parfocal

Answer 11

same plane of focus when switching between objectives to avoid refocusing

Question 12

total magnification

Answer 12

multiply the ocular lens by the objective lens

x10 oculars and a x45 objective would give a total magnification of x450

Question 13

substage

Answer 13

usually attached below the stage, consists of the condenser and the iris diaphragm

Question 14

iris diaphragm

Answer 14

regulates the amount of illumination on the tissue section. Varies with different objectives

Question 15

polarizing microscope

Answer 15

primarily used in histology to identify crystals such as talc, silica, or urate. Examines tissue for anisotropism and birefringence

Question 16

anisotropism

Answer 16

having unlike properties in different directions, appears bright against a dark background when the optical paths of the polarizer and analyzer are crossed

Question 17

birefringence (double refraction)

Answer 17

transmitting light unequally in different directions, appears bright against a dark background when the optical paths of the polarizer and analyzer are crossed

Question 18

polarizer

Answer 18

positioned between the light source and the specimen

Question 19

analyzer

Answer 19

positioned between the specimen and the eye

Question 20

phase contrast microscope

Answer 20

used for the examination of unstained specimens, especially living cells
allows transparent objects to be seen clearly
not typically used in histology

Question 21

darkfield microscope

Answer 21

objects appear self luminous on a dark background when hit by oblique light
objects appear much larger than they are and this makes it easier to see fine structures
typically used to study unstained microorganisms or silver grains in radioactive staining
rarely used in histopathology

Question 22

fluorescence

Answer 22

an optical phenomenon in which light of one wavelength is absorbed by a substance and almost instantly reemitted as light of a longer wavelength

Question 23

fluorescence microscopes

Answer 23

usually use mercury or halogen lamps

Question 24

exciter

Answer 24

a filter placed between the light source and the specimen, obscures all visible light except for the desired wavelength

Question 25

barrier

Answer 25

a filter placed in the eyepiece that absorbs all UV rays and allows only visible light rays to pass. Protects the eyes from damaging UV and reduces non-specific fluorescence so that the object is seen as a bright object against a dark background

Question 26

autofluorescence

Answer 26

also known as natural fluorescence or primary fluorescence
ex collagen fluoresces naturally
some tissues autofluoresce the same as a fluorochrome, esp when using blue light

Question 27

fluorochrome

Answer 27

a dye that fluoresces when excited by UV light

tend to be maximally excited in the blue range

Question 28

immunofluorescence

Answer 28

labeling with a fluorescent dye such as fluorescein isothiocyanate (FITC)

Question 29

direct immunofluorescence

Answer 29

labeled primary antibodies are applied directly to tissue sections to combine with antibodies or antigens in the tissue

Question 30

indirect immunofluorescence

Answer 30

unlabeled primary antibody is applied then a secondary FITC labeled antibody is applied, which is conjugated against the species of the primary antibody
more sensitive than direct immunofluorescence

Question 31

non-immunological fluorescence

Answer 31

acid-fast bacilli (bacteria) and amyloid

Question 32

amyloid

Answer 32

an abnormal protein that is produced in your bone marrow and can be deposited in any tissue or organ
can be stained with thioflavin T

Question 33

acid-fast bacilli

Answer 33

can be stained with auramine-rhodamine

Question 34

Neurofibrillary plaques and tangles

Answer 34

can be stained with thioflavin-S

Question 35

transmission electron microscopy

Answer 35

electrons pass through clear areas ans deflect off of dark areas. useful in the diagnosis of muscle and kidney disease and in tumor identification

Question 36

scanning electron microscopy

Answer 36

renders a 3 dimensional image
greater depth of focus compared to transmission, but less resolving power
typically used in research settings