Pathology is the branch of medicine concerned with the study of changes in cell structure and function as a result of the disease.
Causes of the disease usually fail under one of two general headings:
i.e. a weak and malnourished person will more readily succumb to pneumo-ma than one who is healthy and able to resist an invasion of bacteria; in this case, the state of health was a predisposing cause, the bacteria the immediate cause.