a. For the purpose of this article, the phrase "compensable occupational disease" shall include all diseases arising out of and in the course of employment, which are due in a material degree to causes and conditions which are or were characteristic of or peculiar to a particular trade, occupation, process or place of employment.
b. Deterioration of a tissue, organ or part of the body in which the function of such tissue, organ or part of the body is diminished due to the natural aging process thereof is not compensable.