Final answer:
Frostbite occurs when ice crystals form in skin or deeper tissues at freezing temperatures, leading to cell rupture and potential irreversible tissue damage, which may require amputation if not treated properly.
Step-by-step explanation:
When ice crystals form in the skin or deeper tissues after exposure to temperatures 32 degrees Fahrenheit or colder, a condition known as frostbite occurs. The body's natural response to cold involves constricting arterioles to minimize heat loss, which is particularly critical in the extremities like fingers and toes. When exposed to freezing temperatures, the conservation of body core heat can lead to the freezing of skin tissues, resulting in the formation of ice crystals within tissue cells.
This formation of ice crystals has a damaging effect on tissues because it causes the expansion of water, which then ruptures the delicate cell membranes, leading to irreparable damage. If left untreated, it can lead to more severe damage such as gangrene, potentially requiring amputation of the affected areas. Hence, it's critical to re-warm frostbitten areas gradually and seek medical attention promptly to mitigate the risks of permanent damage.