Your cardiovascular system includes not only your heart, but also your blood vessels which include arteries and capillaries which carry blood through the body. Blood shuttles oxygen from the lungs, food for our tissues, hormones and a host of other cells with specific roles and functions.

Your Heart is an organ providing the driving force of the entire cardiovascular system. It rhythmically contracts at a self-generated pace, although heart rate can be modified by numerous external effects. The contractions propel blood through the vascular system to allow delivery of oxygen, carbon dioxide, and food to individual tissues. The organ is enclosed in a double-walled sac called the pericardium. This sac protects the heart, anchors its surrounding structures, and prevents overfilling of the heart with blood. It is located in front of the vertebral column and behind the breast bone. The size of the heart is about the size of the person’s fist and has a mass of between 250 grams and 350 grams. It is composed of three layers, all of which are rich with blood vessels. The heart has four chambers, two superior atria and two inferior ventricles. The atria are the receiving chambers and the ventricles are the discharging chambers. The flow of blood through the heart is done by four valves which are the tricuspid valve, the mitral valve, the aortic valve, and the pulmonary valve.

Your Vascular System is a closed circuit of branching blood vessels which carries and transfers blood products to organs and tissues. It is composed of three types of vessels:

1. Arteries
   1. These are branching, elastic tubes which carry blood away from your heart. The blood contained within them is usually oxygen-rich and under high fluid pressure. The primary exception to this rule is the pulmonary arteries, which carry oxygen-poor blood from the heart to the lungs.
2. Veins
   1. These are thinner walled branching vessels that carry low fluid pressure blood (generally oxygen-poor) back to the heart. The only veins which carry oxygen-rich blood are those that return blood from the lungs to the heart.
3. Capillaries
   1. These are tiny intermediate vessels between arteries and veins where gas and food exchange occurs within individual tissues. In order to reach the many cells of tissues which depend on the vascular system as a supply line, capillaries split into elaborate branching networks of interconnecting, microscopic vessels.
4. Your Blood is the fluid which travels in the vascular system. Blood is actually a mixture of components:
   1. Plasma - a fluid substance which is mostly water, salts and protein
   2. Red Blood Cells (RBC) - cells which give blood its characteristic red colour and ability to transport oxygen
   3. White Blood Cells which mediate inflammation (for example, in response to infection).

Your lungs are two sac-like organs which occupy the chest cavity and due to a negative pressure created by breathing in, take in air from your surroundings. They contain large numbers of tiny, specialized air sacs which collect air into tunnels where blood in capillaries can intermingle with them and engage in gas exchange.

Your Neuro-endocrine System coordinates different functions of the body. It is primarily composed of the interaction of the nervous system and organs which produce hormones. In part, this system regulates effects to the heart and vascular system. 
 
Heart Disease comes in all forms but the main ones you should know about are the ones you can do something about by changing your lifestyle.