Español
PDFs by language
Our 24/7 cancer helpline provides information and answers for people dealing with cancer. We can connect you with trained cancer information specialists who will answer questions about a cancer diagnosis and provide guidance and a compassionate ear.
Live Chat available weekdays, 7:00 am - 6:30 pm CT
Call us at 1-800-227-2345
Available any time of day or night
Our highly trained specialists are available 24/7 via phone and on weekdays can assist through online chat. We connect patients, caregivers, and family members with essential services and resources at every step of their cancer journey. Ask us how you can get involved and support the fight against cancer. Some of the topics we can assist with include:
For medical questions, we encourage you to review our information with your doctor.
The cardiovascular system or circulatory system is made up of structures and organs that aid in blood flow throughout the body.
The main goals of this system are to:
The organs of the cardiovascular system include the:
The heart is a muscle that pumps blood to organs and tissues in the body.
The heart has 2 upper chambers (atria) and 2 lower chambers (ventricles) that work together to move blood through the body. Heart valves keep blood moving in the right direction and prevent flow backwards.
Veins carry oxygen-poor blood from tissues in the body to the heart. Oxygen-rich blood is carried away from the heart through the arteries.
The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.
Last Revised: May 19, 2025
American Cancer Society medical information is copyrighted material. For reprint requests, please see our Content Usage Policy.
Sign up to stay up-to-date with news, valuable information, and ways to get involved with the American Cancer Society.