BSC 215 Chapter Notes - Chapter 4: Stratified Squamous Epithelium, Simple Squamous Epithelium, Basal Lamina
Document Summary
Biopsy: tissue sample is removed from patient, prepared, and examined under microscope. Histology: study of tissues (third level of organization) Tissue: group of structurally and functionally related cells and their external environment that together perform common functions, have an extracellular matrix. Extracellular matrix (ecm): consists of ground substance and protein fibers, provide tissues with strength to resist stretching and other forces, direct cells to proper places, hold cells in position, regulate development, mitotic activity, and survival of cells. Ground substance: shapeless, gel-like, makes up most of ecm, consist of the interstitial fluid, glycosaminoglycan, proteoglycans, glycoproteins. Epithelial tissues: found on every internal and external body surface, primarily act as barriers between the body and external environment: protection, immune defenses, secretion: produce substances such as oil or hormones, transport into other tissues: selectively permeable, sensation. Avascular: lacks blood vessels, which puts a limit on how thick this tissue can be.