Cytology, Histology Flashcards Preview

Foundations > Cytology, Histology > Flashcards

Flashcards in Cytology, Histology Deck (34):
1

– routine laboratory microscope used for studying tissue sections

Light (bright field) microscope

2

– used to study cytology or internal structures of cells; study of electron micrographs

Transmission electron microscope (TEM)

3

–used to study the surface features of cells and tissues; obtain a 3-dimensional picture of the tissue

Scanning electron microscope (SEM)

4

– permits one to determine whether biological materials have different refractive indices along different optical axes

Polarizing microscope

5

– used to study living tissue; works on principal of different refractive indices of cellular and sub-cellular components

Phase microscope

6

– a modification of the phase microscope used for the study of living tissue

Interference microscope

7

– uses UV light as the light source; used to examine the presence of fluorescent material in tissue sections

Fluorescence microscope

8

– uses a laser energy beam; used to optically section a cell and with the appropriate computer equipment can reconstruct a 3-D image of the cell

Confocal scanning microscope

9


a. Purpose: to preserve tissue morphology and chemical composition.
Accomplished by rendering tissue insoluble by precipitating proteins and carbohydrates (stabilizes the structure)
b. Commonly used fixatives: 10% buffered formalin, glutaraldehyde, alcohol, osmic acid

Fixation

10


a. Purpose: to remove water from tissues so that tissue is miscible with clearing agent
b. Alcohols commonly used as dehydrating agents

Dehydration

11


a. Purpose: to replace alcohol with an agent miscible with paraffin
b. Toluene, xylene, benzene

Clearing

12


a. Purpose to replace clearing agent with embedding material
b. Paraffin, methacrylate, celloidin, gelatin

Infiltration and embedding

13


a. Purpose: to produce thin sections through which light will pass. Paraffin sections cut from 5-7 μm thick
b. Done on an instrument known as a microtome

Sectioning

14


a. Purpose: to impart color to a tissue
b. Hematoxylin and eosin (H & E)

Staining

15

Artifact due to lysosomal digestion of the cells.

Post-mortem degeneration –

16

Artifact due frequently to reagents used in preparing paraffin sections, resulting in empty to clear spaces which during life were occupied by tissue components.

Shrinkage –

17

Artifact that occurs when formalin is not properly buffered.

Precipitates –

18

Artifact due to defect in paraffin section.

Wrinkles and folds –

19

Artifact due to defect in knife, resulting in the tearing or scraping of the tissue when the section is cut.

Nick in the microtome knife –

20

Cause of artifacts frequently due to pinching of the tissue when removing tissue from the body.

Mishandling of the tissue –

21

the atomic groups upon which color of a stain depends (-N=N-)

Chromophore –

22

Stain that has chromophore associated with the basic radicle (cation; +):

basic stain

23

structures in the cell or tissue that love basic stains; e.g. nucleus – large number of PO4(3-) radicles (acid radicles)

DNA – chromosomes; heterochromatin
RNA – nucleolus and cytoplasmic ribosomes

Basophilic substances –

24

Blue to purple basic stain:

Hematoxylin

25

Dye has the chromophore associated with the acid radicle (anions; -):

Acidic or anionic stain

26

structures in the cell or tissue that love acid stains
e.g. proteins – large number of basic groups (cations; +) associated with the side chains

Acidophilic substances (eosinophilic substances) –

27

red to pink acid stain?

Eosin

28



a. a stain for connective tissue (collagen) rather than cells
b. e.g., Masson's, Mallory's

Trichrome stain

29



a. a stain for the elastic fibers or elastic tissue in connective tissue
b. e.g., aldehyde fuchsin; orcein; resorcin-fuchsin

Elastic stains

30



a. a stain for reticular fibers in connective tissue; also used in staining cells of the central nervous system
b. connective tissue fibers love silver (argyrophilic) and stain black

Silver impregnation stains

31

Nucleic acids (DNA and RNA) stains:

Feulgen staining reaction

luekofuchsin (shiff reagent) --> aldehyde shiff (product, colored)

32

Carbohydrate (e.g., glycogen) stain


Periodic acid-Schiff reaction (PAS)

33

Fat stains:

a. Oil red O (stains fats red) and Sudan black (stains fats black) commonly used
b. soluble in both alcohol and fats

34

Protein stains?

a. Specific stains for amino acids or groups of amino acids available, but no longer used
b. Immunocytochemistry is used extensively for localizing specific proteins in cells or tissues