Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Arteriovenous Malformations ?
    ### Response:
    Arteriovenous malformations (AVMs) are defects in your vascular system. The vascular system includes arteries, veins, and capillaries. Arteries carry blood away from the heart to other organs; veins carry blood back to the heart. Capillaries connect the arteries and veins.
    