Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Aneurysm ?
    ### Response:
    The force of blood pushing against the walls of an artery combined with damage or injury to the arterys walls can cause an aneurysm.
                
Many conditions and factors can damage and weaken the walls of the aorta and cause aortic aneurysms. Examples include aging, smoking, high blood pressure, and atherosclerosis (ath-er-o-skler-O-sis).
    