W10 Cellular pathology Flashcards
Cells
Living, more or less self-sufficient entities that may form more complex structures. Cells are surrounded by a membrane
Tissues
The “more complex structures”. Interwoven masses of cells and extra cellular material
Histology
Study of the “more complex structures” = tissues
Organization at 4 different levels
Tissue structure - how cells combine together with extracellular material and each other to form a tissue
Cellular structure - how a cell is shaped, and how the components inside cells are organized to support that cells specific function
Sub-cellular structure - detailed analysis of organelles and inclusions
Histochemical structure - molecular analysis of cellular structure
Histopathology
The study of tissues affected by disease
Useful in making a diagnosis and in determining the severity and progression of a disease
Epithelial tissue
Is made of cells arranged in a continuous sheet with one or more layers; has apical & basal surfaces
A basement membrane separates the epithelial layer from the underlying connective tissue
Two types of epithelial tissues: 1) Covering & lining epithelia; 2) Glandular epithelium (endocrine and exocrine)
The number of cell layers & the shape of the cells in the top layer are used to classify epithelium
Epithelial tissue classification
Number and distribution of cell layers
Simple Epithelium - one cell layer.
Stratified Epithelium - two or more cell layers.
Pseudostratified Epithelium - cells are all anchored to the basement membrane (i.e. one cell layer) but not all cells reach the apical surface (nuclei do not align, does not look like one cell layer).
Shape of the top layer of cells
Cuboidal, columnar, squamous
Connective tissue
There are two main groups: 1) Connective tissue proper; 2) Specialised connective tissue.
Contains:
Many different cell types including: fibroblasts, macrophages, mast cells, and adipocytes.
Connective Tissue Matrix made of two materials: 1) ground substance - proteins and polysaccharides; 2) fibres – reticular, collagen and elastic
Connective tissue classification
Loose Connective – fibres & many cell types in gelatinous matrix, found in skin & surrounding blood vessels, nerves and organs
Dense Connective – bundles of parallel collagen fibres & fibroblasts, found in tendons and ligaments
Cartilage
Made of two main components: 1) collagen & elastin fibres embedded in a matrix of glycoproteins; 2) cells called chondrocytes. There are 3 types
Hyaline cartilage
Weakest, most abundant type. Found at end of long bones, & structures like the ear and nose
Elastic cartilage
Maintains shape, branching elastic fibers distinguish it from hyaline
Fibrous cartilage
Strongest type, has dense collagen & little matrix, found in pelvis, skull & vertebral discs
Bone
Composed of bone cells - osteoprogenitor cells, osteoblasts, osteocytes and osteoclasts – suspended in a matrix consisting of collagen fibres and minerals
Bone development can be
1) Membranous – as in flat bones, clavicle or mandible; 2) Endochondral – as in limb and vertebral column bones
Mature bone may be
1) Compact – concentric circular layers (lamellae) organised in lacunae and a central canal (Harvesian system); 2) Trabecular – slender interlacing parallel lamellae with marrow within the spaces
Skeletal muscle
Voluntary, striated, striations perpendicular to the muscle fibers and it is mainly found attached to bones.
Organized in myofibres with nuclei peripherally located. Forms a lined up banding pattern from one cell to another when observed longitudinally
Cardiac muscle
Involuntary, striated, branched and has intercalated discs. Cells smaller than skeletal muscle with nuclei centrally located
Smooth muscle
Involuntary, non-striated, spindle shaped and is found in blood vessels & the GI tract. Cells vary in size and have a fusiform shape. Nuclei observed in different positions
Ectoderm
Develops into nervous tissue and epithelial tissue
Mesoderm
Develops into epithelial tissue, connective tissue and muscle tissue
Endoderm
Develops into epithelial tissue
