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.
A covered woundâ¦ Dries out and forms a scab Scabs may be the bodyâs natural way of protecting from germs, but a scab is not the best way to heal. Scabs impede the wound healing process by creating a barrier of dead, dried-out cells that healthy skin cells must work their way under to form new tissue and heal. Minimizes the appearance of scars