Introduction In biology, pigments are defined as substances occurring in living matter which absorb visible light (electromagnetic energy within a narrow band which lies approximately between 400 and 800 nm). The various pigments may greatly differ in origin, chemical constitution…
Introduction This is a large group of compounds with the general formula C n (H 2 O) n . The role of carbohydrates in cellular metabolism has been known for many years but carbohydrates have more recently been implicated in…
Introduction During embryonic development, the ectoderm and endoderm are divided by a germ cell layer, the mesoderm or mesenchyme. The term mesenchyme comes from the Greek ‘mesos’ meaning middle and ‘enchyma’ meaning infusion. Connective tissues and muscle develop from the…
Introduction Transforming a tissue specimen from fixed material to stained sections is a multiple step process which began as separate manual tasks. Indeed, histology in the last century has been the slowest of the laboratory medicine departments to innovate and…
Introduction Hematoxylin and eosin (H&E) is the most widely used histological stain. It is simple to use, easy to automate and demonstrates different tissue structures clearly. Hematoxylin stains the cell nuclei blue-black, showing clear intranuclear detail, whilst eosin stains cell…
Introduction The physicochemical mechanisms of most histological stains are now understood. Detailed accounts and general overviews are to be found in the references and further reading at the end of this chapter. Histological staining methods from acid dyes to silver…
Introduction Resins are used to provide exceptionally strong support in tissue preparation for microscopy. Currently available resins include epoxy and acrylic formulations which can be used in standard histological techniques, but also may be useful in specialized techniques such as…
Introduction Microtomy is the means by which tissue is sectioned and attached to the surface of a glass slide for further microscopic examination. The basic principles are applicable to both paraffin and frozen sections although most microtomy is performed on…
Introduction Proper handling of tissue specimens is critical to ensure that an accurate diagnosis is obtained from patient tissue samples. Whilst technological advances have streamlined processing, the principle steps remain the same: fixation, dehydration, clearing and infiltration. Regardless of the…
Introduction The initial dissection and preparation of any specimen for histological/microscopic analysis involves more than simply the transcribed macroscopic description and sampling of the specimen. Whilst the dissection and laboratory area are often perceived as the two key elements of…