Cell Pathology Coursework: practical in week 25/26,cut and prepare tissue sections from blocks and then stain to identify cellular features. Identif i cation of tissue features will also form part of the practical examination - 1) Normal and abnormal histology of cells and tissues and relationship to pathophysiology of selected conditions. - 2) Understand the cellular pathological aspects of a range of common conditions and diseases. - 3) The role of microscopy in dif f erential diagnosis of selected conditions. - 4) The role of specif i c tissue staining and immunocytochemistry in dif f erential diagnosis of selected conditions. - 5) Advances in cancer biology. - 6) Understanding the impact of molecular biological techniques to cellular pathology. Week 18: Ultra-structural Features of Muscle, Bone, Connective Tissue - Haematoxylin and eosin staining: haematoxylin is isolated from the heartwood of the blackwood tree Haematoxylum campechianum, It is historically used as a textile and paper dye. When oxidised to haematein forms complexes with Al3+ or Fe3+ ions. This complex is then able to stain acidic, negatively charged structures like DNA Blue - Eosin B is blue, eosin Y is yellow, Binds to basic structures - proteins: arginine and lysine side chains are basic - and forms complex salts, stains red/pink/purple - Muscles are composed of fascicles separated by perimysium - Perimysium (dense irregular connective tissue) - Sarcomere, myosin f i lament - The actin f i lament is stabilised by tropomyosin f i laments wrapped around - Troponin regulates myosin binding to the thin f i lament in a Caesponsive manner - Smooth muscle: Structural dif f erences: No transversal tubules (T-tubules), No myof i brils, The sarcoplasmic reticulum forms a loose network, The thick f i laments have no particular organisation, The thick f i laments have more cross-bridges, The thin f i laments are attached to dense bodies that form a network with intermediate
f i laments composed of desmin, During contraction the cell shortens and twists, No tendons - Functional dif f erences: @aons enter from the extracellular f I uid, In the sarcoplasm Ca2+ ions bind to calmodulin, On Ca2+ ion binding calmodulin activates myosin light chain kinase, an ATPase that initiates contraction, smooth muscle cells are able to operate over a wide range of distances (plasticity; organs with large volume change) - Smooth muscle can be tonally active (iris of the eye,vascular smooth muscle) (multiunit smooth muscle) - or rhythmically active (uterus, gastro-intestinal tract, bladder) (single unit) - Connective tissues: forms from mesenchyme in embryo, variable degree of vascularity and extracellular matrix, binds tissues together, provides structural support for other tissues, protects and insulates other tissues, transportation - Connective tissue is removed during histological procedures, soluble materials and nutrientsdiffusethroughgroundsubstance,fluid,(glycoproteins,proteoglycansand glycosaminoglycans) - Fibres: collagen, elastin and reticular f i bres - Primary blast cells secrete ground substance and f i bres, produce mature cells i.e. f i broblasts, chondroblasts, osteoblasts and HSCs - Example: Areolar connective tissue - Adipose tissue - Oil Red O stains fat tissue -