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.
When the fibrinogen and platelets come into contact with air, they begin breaking apart and form into a thread-like substance called fibrin. This fibrin acts as a glue-like bandage of sorts to trap the blood and form a clot. When that clot begins to dry it forms what is referred to as a scab. With a basic understanding of how scabs form and their purpose, it's easy to see the importance that they serve in the healthy healing of cuts and other bleeding injuries. The body is an amazing thing and in an otherwise healthy person it will always aid in the protection and healing of itself.