Elizabeth Martin and Robert Hine. Latest Edition (7 ed.) Fully revised and updated, the sixth edition of this dictionary provides comprehensive coverage of biology, biophysics, and biochemistry, as well as key terms from medicine and palaeontology.
For example, if someone scratches a mole until it bleeds, the resulting lesion, a crust, is now a secondary skin lesion. The most common secondary skin lesions include: 1  crust: a crust, or a scab, is created when dried blood forms over a scratched and irritated skin lesion. 2  ulcer: typically caused by a bacterial infection or physical trauma. 3  scale: patches of skin cells that build up and then fall off the skin.
Necrotic tissue is dead tissue, which usually results from an inadequate local blood supply. Necrotic tissue contains dead cells and debris that are a consequence of the fragmentation of dying cells.Necrotic tissue changes color from red to brown or black/purple, as it becomes more dehydrated.Finally, it forms a black, dry, thick, and leathery structure known as eschar. This can be seen in a wide variety of wound types, including burns and all types of chronic wounds.In contrast, slough is a yellow fibrinous tissue that consists of fibrin, pus, and proteinaceous material.ecrotic tissue changes color from red to brown or black/purple, as it becomes more dehydrated. Finally, it forms a black, dry, thick, and leathery structure known as eschar. This can be seen in a wide variety of wound types, including burns and all types of chronic wounds.