Medical Applications fo Tissue Processing and Examination

Question 1

Step 1 Fixation

Answer 1

Chemical: Formalin, glutaraldehyde
Purpose: preservation of normal tissue architecture after death, fixatives coagulate or precipitate proteins, renders the structures resistant to further processing

Question 2

Step 2 dehydration

Answer 2

chemical- graded series from 50-100% of ethanol

purpose- remove water from the tissue specimen and replace it with alcohol

Question 3

step 3 clearing

Answer 3

chemical- xylene

purpose- prepares the tissue for the embedding medium, paraffin

Question 4

step 4 embedding

Answer 4

chemical- paraffin

purpose- tissue is infiltrated with paraffin so that it is hard enough to section

Question 5

step 5 sectioning

Answer 5

no chemical

purpose- tissue is cut into thin sections with a microtone

Question 6

step 6- mounting

Answer 6

no chemical

purpose- cut paraffin section is placed on a glass microscope slide

Question 7

step 7- staining

Answer 7

chemical- various chemicals used

purpose- to impart contrast to tissue structures so that they may be distinguished upon microscopic observation

Question 8

Hematoxylin

Answer 8

affinity- RNA, DNA, ribosomes, rER
color- blue
basic dye

Question 9

Eosin

Answer 9

affinity- secretory vesicles, sER, lysosomes, mitochondria, and type I collagen
color- pink
acid dye

Question 10

Feulgen reaction

Answer 10

affinity- DNA

color- magenta

Question 11

Mallory triple

Answer 11

affinity- nuclei, muscle, collagen, hyaline cartilage
color- nuclei= red
muscle= red to orange
collagen= blue
hyaline cartilage= blue

Question 12

PAS reaction

Answer 12

affinity- carbohydrates

color- magenta

Question 13

Osmic acid

Answer 13

affinity- lipids

color- black

Question 14

Verhoeff

Answer 14

affinity- elastic fibers

color- black

Question 15

Silver methods

Answer 15

affinity- intermediate filaments or nerve cells, glial cells, and reticular fibers
color- black

Question 16

Trypan blue

Answer 16

affinity- macrophages

color- blue

Question 17

Prussian blue

Answer 17

affinity- hemosiderin, ferric iron

color- blue

Question 18

Nissl

Answer 18

affinity- ribosomes

color- blue

Question 19

Iron hematoxylin

Answer 19

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

Question 20

**Metachromasia

Answer 20

given stain imparts different colors to the tissue, shifts the labeling of the dye molecule based on density, not all cells show this, seen in granulated mast cells that are imparted by heparin, the toludine blue dye in the mast cells is denser in some parts than other (gives a blue appearance to a red appearance)

Question 21

**PAS

Answer 21

used in diagnosis of kidney disease, glycogen storage disease, and AAT
AAT- is misfolded and accumulates in the rER, used for thickened basement membranes, can see accumulations of PAS positive proteins

Question 22

**Mallory Triple

Answer 22

trichrome stain, cocktail, used in diagnosis of pulmonary fibrosis, collagen is shown as blue, shoes an abnormal accumulation of collagen causing lung inflation to be restricted, pattern of breathing becomes shallow and rapid, imparts different colors to diff tissue structures based on molecular distribution

Question 23

**Congo Red

Answer 23

identify extracellular accumulation deposits of amyloid, can determine if there are amyloid deposits in the wall of a blood vessel, amyloid= pathological accumulation of protein in tissue, ordinary light it will appear red, in polarized light it will appear red-green

Question 24

**Frozen tissue samples

Answer 24

sections are thicker and fine detail is lost compared to a routine tissue sample