End Of Fixation

Question 1

SECONDARY FIXATION

Answer 1

• To improve the demonstration of particular substances
• To make special staining possible (secondary fixatives as mordants)
• To ensure further and complete hardening and preservation of tissues

Question 2

Technique whereby a primary fixed tissue is placed in aq. Solution of 2.5% - 3% potassium dichromate for 24hrs

Answer 2

Post-Chromatization

Question 3

• Post-Chromatization
Technique whereby a primary fixed tissue is placed in aq. Solution of__________ for____

Answer 3

2.5% - 3% potassium dichromate

24hrs

Question 4

: Tap water
Process of removing excess fixatives

Answer 4

WASHING OUT

Question 5

WASHINGTON OUT

• Excess chromates, formalin, osmic acid

Answer 5

Tap water

Question 6

WASHINGTON OUT

Picric acid

Answer 6

50% - 70% Alcohol

Question 7

WASHINGTON OUT

• Mercuric fixatives

Answer 7

Alcoholic lodine

Question 8

DIFFICULTIES IN IMPROPER FIXATION

Answer 8

• Failure to arrest autolysis
• Tissues are brittle and too hard
• Shrinkage and swelling of cells
• Tissue soft consistency
• Presence of artifact pigments
• Removal of soluble substances
• Incomplete result in other procedures