# The Cardio-Respiratory System

### The Cardiovascular System

The Cardiovascular System consists of The Heart, Blood Vessels and Blood.

Blood vessels carrying blood away from the heart are defined as arteries. Similarly, blood vessels carrying blood towards the heart are defined as veins.

Cardiac Cycle in brief:

1. Deoxygenated Blood enters the RIGHT ATRIUM through the largest vein known as the VENA CAVA
2. The SINOATRIAL NODE (SA NODE) signals for the atrium to contract, thereby forcing blood through the TRICUSPID Valve to the RIGHT VENTRICLE
3. The ATRIOVENTRICULAR NODE then signals the ventricles to contract pushing the blood through the PULMONARY VALVE to the LUNGS through the PULMONARY ARTERY
4. Upon Oxygenation, Oxygenated Blood is sent to the heart through the PULMONARY VEIN
5. Oxygenated blood enters the LEFT ATRIUM and is shunted to the LEFT VENTRICLE through the BICUSPID VALVE
6. The LEFT VENTRICLE contracts and shunts blood to the body through the AORTIC VALVE and finally the largest artery in the human body known as AORTA