Final answer:
In cold conditions, a nurse looks for signs of cellular injury in the form of frostbite, characterized by vasoconstriction, whiteness, or paleness in the fingers and toes, hardness, and a waxy appearance of the skin.
Step-by-step explanation:
When assessing a homeless man's fingers and toes for frostbite during extremely cold conditions with a windchill factor of -10 degrees Fahrenheit, the nurse would be looking for signs of cellular injury caused by freezing. Frostbite occurs when the tissue freezes, and this is due to vasoconstriction, which is the body's natural response to cold that reduces blood circulation to the extremities to conserve core body heat.
The possible cellular injury associated with frostbite includes ice crystal formation within cells, which can lead to cell membrane damage, dehydration, and eventually, tissue necrosis. The affected areas might appear white or pale due to the lack of blood flow and, if left untreated, can progress to gangrene, necessitating amputation. Early signs of frostbite include numbness, a loss of feeling in the fingers and toes, and a hard, waxy-looking skin.