Tissue Preparation And Microscopy

Front 1

what are the steps of preparation of a specimen for viewing?

Back 1

fixation, dehydration, embedding

Front 2

what are the steps from fixation to embedding in wax?

Back 2

place tissue in eg 10% formalin fixative
dehydrate by inc percentage of ethanol in solution
remove water and replace with wax-solvent (miscible with ethanol; dissolves wax)
embed oriented specimen in molten wax

Front 3

eg what a wax used for embedding; what is its function

Back 3

paraffin; embeds tissue-infiltrates and frames

Front 4

what tool is used to cut specimen in to sections?

Back 4

microtome

Front 5

how is wax removed from tissue specimen?

Back 5

slide is placed in water-bath, sections float and separate and by tilting slide facilitate sticking of tissue to slide

Front 6

what must occur after dissolving wax? how?

Back 6

hydration by passing section from xylene (chemical used to dissolve paraffin) through series of dec concentration of alcohol until specimen is hydrated

Front 7

what are the 2 components of dyes? what are their functions?

Back 7

chromophore group- chemical moiety that is responsible for its color
auxochrome- binds to cellular components

Front 8

what are the 2 usual functional groups of auxochrome group of dye?

Back 8

amino (has positive charge)- basic dye
sulfate (has neg charge)- acidic dye

Front 9

what is the most routinely used dye? what does each component bind and what color?

Back 9

heaxtoylin- binds to basophilic (neg charged) nuclear components like DNA and RNA- stains blue
esoin- binds pos charged acidophilic- stains pink to red

Front 10

what is advantage of trichrome stain?

Back 10

uses aniline blue which demonstrates and distinguishes collagen from other tissue components

Front 11

what is the significance of enzymatic staining? in general, how does it occur?

Back 11

specific enzyme may be made visible by localization of its activity
bind coloring agent to substrate

Front 12

what reaction selectively demonstrates molecules containing sugars with adjacent hydroxyls? (polyhexoses and hexosamines)
eg of structures in these tissues stained?

Back 12

Periodic Acid-Schiff (PAS) rxn
-tissue components include glycogen, epithelial mucins in goblet cells, proteoglycans in basement membranes

Front 13

what does argyrophilic silver staining reveal? what color is the stain?

Back 13

glycoprotein coating of reticular fibers that reduces silver resulting in black stained fibers

Front 14

what is the term for the working cell in the organ you are looking at?

Back 14

parenchyma

Front 15

what term is the connective tissue reticular fibers which structurally hold everything together?

Back 15

stroma

Front 16

define function of fluorescent antibody technique

Back 16

fluorescent dye with antibody binds to specific antigens on tissues you want to visualize
-antibody labeled with marker (eg enzyme), then provide substrate bound to coloring agent

Front 17

define function of indirect immunofluorescene or cytochemistry- what is the significance?

Back 17

visualization of a tissue using 2 antibodies where target structure visualized is bound to second antibody
-allows more control and inc specificity

Front 18

what are eg of common artifacts that affect ability to interpret image?

Back 18

-bruising/splitting from cutting; poor preservation
-misleading orientation of specimen on wax
-wrinkles
-dirt, etc

Front 19

the smaller the distance between two points that can be resolved (deciphered)...the what of the resolution?

Back 19

the greater the resolution or resolving power of that instrument

Front 20

how are electrons in transmission electron microscope utilized in viewing? how is resolution compared to light microscope?

Back 20

-electrons are attracted to tungsten filament by very high electrical potential and accelerated down column where they interact with specimen that is viewed through round viewing port at bottom of column
-much greater resolving power due to wavelength of electron (smaller than visible light)

Front 21

what is function of scanning electron microscope? what is the key difference of its technique?

Back 21

-creates pseudo 3d view- shows SURFACE by creating electronic image as specimen previously coated in metal during prep is bombarded with electrons which induces emission of secondary electrons from metal surface

Front 22

define virtual slide

Back 22

high resolution digital replica of content of histological slide

Front 23

define virtual microscope

Back 23

pan and zoom viewer, that by accessing a virtual slide can closely emulate examining a glass microscopic slide with traditional microscope

Front 24

what is function of scanning electron microscope? what is the key difference of its technique?

Back 24

-creates pseudo 3d view- shows SURFACE by creating electronic image as specimen previously coated in metal during prep is bombarded with electrons which induces emission of secondary electrons from metal surface

Front 25

define virtual slide

Back 25

high resolution digital replica of content of histological slide

Front 26

define virtual microscope

Back 26

pan and zoom viewer, that by accessing a virtual slide can closely emulate examining a glass microscopic slide with traditional microscope

Front 27

what is function of scanning electron microscope? what is the key difference of its technique?

Back 27

-creates pseudo 3d view- shows SURFACE by creating electronic image as specimen previously coated in metal during prep is bombarded with electrons which induces emission of secondary electrons from metal surface

Front 28

define virtual slide

Back 28

high resolution digital replica of content of histological slide

Front 29

define virtual microscope

Back 29

pan and zoom viewer, that by accessing a virtual slide can closely emulate examining a glass microscopic slide with traditional microscope