Histology - Syllabus Overview and Introduction

These flashcards cover the introductory concepts of histology, including terminology, its importance in medicine and forensics, microscopy differences, tissue processing steps, and specific staining techniques.

Histology

The microscopic study of tissues and organs through sectioning, staining, and examining those sections under a microscope; it is derived from the Greek words 'histos' (tissue) and 'logia' (study).

Histos

A Greek root word meaning tissue.

Logia

A Greek root word meaning study.

Microscopic anatomy

A common alternative name used for the study of histology and histochemistry.

Functional bridge of Histology

Histology bridges the gap between anatomy and physiology by showing what happens to tissues at the cellular level.

Diagnostic Histology

The use of tissue examination to diagnose diseases in humans, animals, and plants, and to analyze the effects of treatment.

Forensic Histology

The microscopic examination of tissues used during autopsies and investigations to help explain cause of death.

Light Microscope (Resolving Power)

$$200\,nm$$

Electron Microscope (Resolving Power)

$$0.2\,nm$$

Electron Microscope (Focus mechanism)

Uses electromagnets to focus beams.

Microscope parts (Adjustment)

Includes coarse adjustment and fine adjustment for focusing, and diopter adjustment for lens calibration.

Fixation

The first step in tissue processing used to prevent putrefaction of the tissue using formaldehyde or glutaraldehyde.

Dehydration

The process of replacing tissue water with alcohols at increasingly higher concentrations.

Clearing

The step using xylol or benzene to replace alcohol and make the tissue translucent.

Embedding

Adding paraffin wax to solidify the sample and provide rigidity for sectioning.

Sectioning

Cutting tissue with a microtome using a metal knife to allow light or electrons to pass through.

Staining

The final tissue processing step used to differentiate different components, such as nuclei and cytoplasm.

Haematoxylin and Eosin (H&E) - Nucleus

Results in a blue color for the nucleus.

Haematoxylin and Eosin (H&E) - Cytoplasm

Results in a pink color for the cytoplasm and background.

Periodic acid stain

Used to stain Glycogen for the identification of Storage disease, Ewing's sarcoma, and Candida.

Mucicarmine stain

Used to stain Mucin and identify adenocarcinoma.

Prussian blue reaction (Perl's iron stain)

A special stain used to identify Iron in cases of Hemochromatosis.

Oil-O-Red stain

Used to stain Fat in frozen sections, commonly to identify Fatty Liver.

Trichrome stain

A special stain used to identify collagen, often seen in scars.