Exam 1: Tissue Processing

Question 1

Fixation

Answer 1

Step 1

Use Formalin Glutaraldehyde; preservation of normal tissue after death

Question 2

Dehydration

Answer 2

Step 2

Use Graded series of ethanol; remove water from tissue and replace with alcohol

Question 3

Clearing

Answer 3

Step 3

Use Xylene; prepare tissue for embedding medium

Question 4

Embedding

Answer 4

Step 4

Use Paraffin; tissue is infiltrated with paraffin so that it is hard enough to section

Question 5

Sectioning

Answer 5

Step 5

Cut tissue into thin sections with a microtome

Question 6

Mounting

Answer 6

Step 6

Place sections on a glass microscope slide

Question 7

Staining

Answer 7

Step 7

Use various chemicals to impart contrast to tissue structures

Question 8

Acid dyes

Answer 8

negative charge

Question 9

Basic dyes

Answer 9

positive charge

Question 10

Acidophilic

Answer 10

tissue structures that have a positive charge and attract negatively charged dye

Question 11

Basophilic

Answer 11

tissue that has a negative charge and attracts positive dye

Question 12

Metachromasia

Answer 12

stain imparts different colors to tissue

Question 13

Hematoxylin

Answer 13

Blue
Attracts to RNA, DNA, ribosomes, and rER
Use for coagulative necrosis

Question 14

Eosin

Answer 14

pink
attracts to secretory vesicles, sER, lysosomes, mitochondria, and type 1 collagen
Use for coagulative necrosis

Question 15

Feulgen reaction

Answer 15

Magenta
attracts to DNA
can be used to demonstrate nuclear changes in cancer

Question 16

Mallory triple

Answer 16

Nuclei - red
Muscle - red to orange
Collagen - blue
Hyaline cartilage - blue
Can be used to highlight fibrosis

Question 17

PAS reaction

Answer 17

Magenta
Carbohydrates
can be used to see thickened basement membranes in kidney disease, glycogen storage diseases, and alpha1-antitrypsin deficiency in liver cells (hepatocytes)

Question 18

Osmic acid

Answer 18

lipids black

Question 19

Verhoeff

Answer 19

elastic fibers black

Marfan syndrome

Question 20

Silver methods

Answer 20

Intermediate filaments of nerve cells, glial cells, and reticular fibers black

Question 21

Trypan blue

Answer 21

macrophages blue

Question 22

Prussian blue

Answer 22

Hemosiderin (ferric iron) blue

Can be used to demonstrate excessive iron accumulation in hemochromatosis

Question 23

Nissl

Answer 23

Ribosomes blue

Question 24

Iron hematoxylin

Answer 24

nuclear elements, chromosomes, mitochondria, centrioles, and muscle striation dark blue to black

Question 25

Congo Red

Answer 25

identify extracellular depositis of amyloid

Question 26

Immunocytochemistry

Answer 26

uses an antibody tagged with a marker directed to a specific antigen
Direct method is less sensitive than indirect method (more antibodies bind to indirect method)

Question 27

In situ hybridization

Answer 27

Uses complementary nucleic acid probes to specifically identify a nuclei acid sequence
Can be used to identify a cell infected with a virus or specific genes