Question

The method used in fixation process for preparation of tissues is :

• A. Hardening
• B. Stirring
• C. Agitation
• D. Staining

Hint:

The three main goals of Fixation: 1. Prevent Autolysis (kill enzymes). 2. Prevent Putrefaction (kill bacteria). 3. Harden the tissue (to allow for ultra-thin microtome sectioning later).

Answer 1

The Correct Option is A

Step 1: Concept:
This question delves into histopathology techniques, specifically assessing the primary physical characteristics and goals achieved during the "fixation" step of tissue processing.

Step 2: Step-by-step Explanation:

• Fixation is the critical first step in tissue processing for histopathological examination. When fresh tissue is removed from the body, it is soft, fragile, and immediately subject to autolysis (self-digestion by its own enzymes) and putrefaction (bacterial decay).

• To prevent this, tissue is submerged in a chemical fixative (most commonly 10% Neutral Buffered Formalin).

• The primary biochemical effect of fixatives is cross-linking proteins. This chemical cross-linking achieves two major outcomes: it permanently preserves the cellular architecture, and it induces significant physical hardening of the tissue.

• This hardening is entirely intentional and necessary; without it, the soft tissue would simply crush or tear during the subsequent steps of grossing and microtome sectioning (cutting into ultra-thin slices).

• Analyzing other options: "Stirring" and "Agitation" are mechanical actions used to speed up the penetration of fluids, but they are not the defining mechanism of fixation itself. "Staining" is a completely different, later step used to add contrast to the slides using dyes (like H&E).

Step 3: Final Answer:
Hardening is the primary functional method/result achieved during the tissue fixation process.