Histology Flashcards
what are the steps of tissue processing for histology?
Fixation, Embedding, Sectioning and Staining
what is fixation? and the different types
fixation preserves the tissue
chemical fixation uses aldehyde based chemicals to preserve
freezing uses dry ice or liquid nitrogen to preserve
What is embedding?
when the cells are embedded in something to provide support for the tissue when sectioning. paraffin wax most commonly used
what is sectioning?
cutting the tissue into thin sections using a microtome.
What is haematoxylin?
stains acidic (basophilic) structures a purplish colour
what is eosin?
stains basic (acidophilic) structures red or pink
what is PAS staining?
used for staining complex carbohydrates and glycogen. if something is stained with PAS it is PAS +
what is electron microscopy?
uses a beam of electron instead of light to increase resolution to allow smaller structures to be viewed clearly
what are the 2 types of epithelial tissue?
covering epithelia and glandular epithelia
what are covering epithelia?
they cover/line all body surfaces, cavities, tubes
what are glandular epithelia?
secretory epithelia arranged into glands
invaginations of epithelium
also glandular organs
what are simple cuboidal epithelium
a single layer of cube shaped cells which are good for diffusion, secretion and absorption
what are simple columnar epithelium
a single layer of tall, narrow cells which allow movement of substances, absorption and secretion and offer more protection than flatter cells
what are stratisfied squamous epithelium
multiple layers of cells which are cube shaped in the basal layer. they protect against abrasion, a barrier against infection and reduce water loss
what is the pseudostratisfied epithelium
single layer- some layers reach the free surface others do not. they synthesise and secrete mucus and move mucus that contains foreign particles over the surface
