regenerative capacity of human body
I'd say renewing refers to a constant process wheras regeneration applies to wholesale rebuilding due to trauma.

For example, your skin is constantly "renewed" by the undermost cells, adjacent to the basement membrane, dividing to produce new cells that migrate outward. These cells are modified to protect and eventually slough off to feed the mites in your bed. Ditto to cells lining the stomach which are replaced/renewed about ever three days due to abuse of stomach acid and salsa.

Humans can regenerate much of the last joint of a finger, bone and all. I'm not sure if this is age dependent nor how much of the knuckle needs to remain. Search "regeneration of fingers in humans" to find many references to this.