platelet-activating factor {Ans: a complex lipid stored in cell membranes, including those of endothelial cells that line blood vessels and in many other types of cells that can become injured}superficial partial thickness burn {Ans: a first degree burn, a sunburn, characterized by pain. damage epidermis}differentiation {Ans: cells mature and become more specialized}stable cells {Ans: cells that stop regenerating when growth is complete but can resume regeneration if injured}thrombus {Ans: protective clot and subsequent scab}provisional matrix {Ans: third, temporary ecm promotes healing by decreasing blood and fluid loss at the site and attracting and supporting fibroblasts, endothelial cells, and epidermal (skin) cells when injury occurs, increased vascular permeability allows proteins from the plasma to move to the site and form this provisional protective layer}