Question

Write short explanatory notes on the following.
2.1. The effect of tissue processing on specimens. (4marks)
2.2. Wax infiltration.
2.3. Specimen fixation
2.4. Decalcification process. ( 4 marks).
2.5. The use of microwave during tissue processing.

Answer 1

2.1 Effect of tissue processing on specimen

1. Prevents putrefaction and autolysis

2. Hardens the tissue which helps in section cutting.

3. Makes cell insensitive to hypotonic and hypertonic solutions

4. Acts as a mordant

5 induces good optimal contrast which helps in morphological examination

2.2 wax infiltration - wax liquid at temperatures 60 degrees are infiltrated into tissue at 60 degrees and cooled to 20 degress and allows the solidify that helps in cutting consistently

Size of tissues should be 3mm

2.3 specimen fixation is preservation of specimen form decaying by stopping the biochemical reactions

There are two types of fixation they are crosslinking and coagulation fixation

Cross linking involves covalent bond formation with proteins and between them which causes tissue stiffening

Adequate fixation time - fixation time is 3 to 7 days

2.4 decalcification process - it is performed to produce good paraffin sections that will preserve all microscopic elements

They are 4 types -  

1.simple dilute mineral acid such as weak acid , strong acid

2.Electrolytic decalcification

3. Ion exchanging resins with acid decalcifying agents

4. Chelating agents