Final answer:
During an emergency, the autonomic nervous system redirects blood to the heart for increased oxygen and nutrient supply.
Step-by-step explanation:
The autonomic nervous system automatically redirects blood away from other organs to the heart during an emergency. This is part of the sympathetic division of the autonomic nervous system, also known as the fight-or-flight response. The redirection of blood to the heart helps increase oxygen and nutrient supply to this vital organ, enabling it to pump blood more effectively and support the body's response to the emergency.