HLSC 3464U Lecture Notes - Lecture 4: Benign Tumor, Respiratory Epithelium, Cellular Adaptation
Document Summary
Atrophy: shrinking, not as a result of lack of nourishment. Hypertrophy: growth of size of each cell, growth of organelles, growth of metabolic activities. Hyperplasia: increase in number of cells through mitosis. Metaplasia: one type of mature tissue is replaced by another, common (ex. in smokers, respiratory epithelium is replaced by squamous epithelium) Dysplasia: irreversible, looks like stratified squamous but architecture is lost bottom cells are more cuboidal and top cells are more flat, cells are disorganized, each cell looks different, nuclei look different and darker, precursor to cancer. Benign: grow slowly, well-defined capsule/borders, low mitotic index, not invasive, well-differentiated, doesn"t spread, most will not become malignant, can take 5-6 years to grow. Malignant: grow rapidly, not encapsulated/ill-defined borders, high mitotic index, may not be well-differentiated, can spread. All benign tumors are named by origin and suffix -oma . Malignant tumors are named by origin and suffix: -carcinoma = epithelium cancer, -sarcoma = connective tissue cancer, exception is melanoma.
