Histopathology Quiz Questions And Answers

Formalin Solution (10%, unbuffered) is composed of 10 ml Formaldehyde (40%) and 90 ml distilled water. This means that the solution contains 10% formaldehyde, which is achieved by diluting 10 ml of a 40% formaldehyde solution with 90 ml of distilled water. The other options either have different concentrations of formaldehyde or incorrect proportions of formaldehyde and water.

Mercuric chloride is restricted in use because it is toxic, corrosive, and a pollutant. Being toxic means that it can cause harm or even be fatal if ingested, inhaled, or absorbed through the skin. Its corrosive nature means that it can cause severe damage to tissues and materials it comes into contact with. Additionally, it is considered a pollutant because it can contaminate the environment and have harmful effects on ecosystems and human health. Therefore, due to its toxic, corrosive, and polluting properties, mercuric chloride is restricted in use.

Acetic acid is a versatile compound that can act as a denaturing agent, meaning it can disrupt the structure and function of proteins. It can also swell collagen, which is a fibrous protein found in connective tissues. Additionally, acetic acid can be used as a precipitating fixative, meaning it can cause proteins to precipitate out of solution. Lastly, acetic acid is a type of alcohol. Therefore, the correct answer is that acetic acid is all of the above.

Microwave fixation is not suitable for large specimens because it is unable to heat the center of the tissue or organ sufficiently without overheating the outside. This can lead to uneven fixation and potential damage to the tissue structure.

The correct answer is "Fixative is recycled and reused". This is because recycling and reusing fixative can lead to contamination and inconsistent results. Fixative is used to preserve and stabilize biological samples, so it is important to use fresh fixative each time to ensure proper fixation. Recycling and reusing fixative can introduce impurities and compromise the quality of the fixation process.

Formaldehyde is a commonly used aldehyde fixative, but it is not the best fixative for nucleic acids. Other fixatives, such as ethanol or methanol, are more effective in preserving nucleic acids.

Microwave fixation is a method used to fix blocks in a normal saline solution. The correct answer for the temperature and time of fixation is 62°C for 30 seconds. This specific temperature and time combination ensures effective fixation of the blocks, preserving their structure and preventing degradation.

Potassium Dichromate is not an Aldehyde fixative because it is a strong oxidizing agent that reacts with aldehydes, converting them into carboxylic acids. Aldehyde fixatives are used to preserve and stabilize tissue samples by cross-linking proteins, and they typically contain aldehydes such as formaldehyde or glutaraldehyde. Picric Acid, Glutaldehyde, and Mercuric chloride are all examples of aldehyde fixatives commonly used in histology and pathology laboratories.

Fixation is a process used in histology to preserve tissue samples for further analysis. The aim of fixation is to prevent putrefaction, remove excess water from the tissue, prevent osmotic swelling, and prevent lysosomal activity. Rendering the tissue suitable for subsequent staining is not the aim of fixation. Fixation helps to preserve the structure and cellular components of the tissue, making it easier to analyze and study under a microscope. Staining is a separate step in the histology process that involves adding dyes to highlight specific structures or cells in the tissue sample.

Glutaraldehyde cross-links tissue components extensively, making it a better fixative for preserving the morphology of tissues at the electron microscopy (EM) level compared to formaldehyde. This statement implies that glutaraldehyde does not cross-link as extensively as formaldehyde, which is false. Glutaraldehyde actually cross-links more extensively than formaldehyde, resulting in better preservation of tissue structure at the EM level.