Circulatory System

• The cardiovascular system works by the heart pumping blood through blood vessels to deliver oxygen and nutrients to cells while removing waste products, ensuring the body functions properly. The continuous circulation of blood helps maintain the body's overall functioning. 
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  The function of the heart is to circulate blood and oxygen throughout the body and return waste materials, like carbon dioxide, to the lungs for expulsion.
• There are 4 atrias in the heart.
• The function of the right atrium is to recieve deoxygenated blood from the superior (upper body) and inferior vena cava (lower body)
• The function of the left atrium is to receive oxygenated blood from the pulmonary veins which carry blood from the lungs.
• The function of the left ventricle is to pump oxygenated blood to the rest of the body via the aorta.
• The function of the right ventricle is to pump deoxygenated blood to the lungs via the pulmonary artery.
• The function of the ventricles is to pump blood out of the heart into arteries that lead to other parts of the body.
• The atrium is one of the two upper chambers in the heart that receives blood from the circulatory system
• Tricuspid valve allows the blood to flow from the right atrium to the right ventricle. This prevents blood from flowing backward from the right ventricle to the right atrium.
• Pulmonary valve allows the blood to pump from the right ventricle to the pulmonary artery. This artery leads to the lungs, where the blood picks up oxygen. This valve prevents blood from going backward from the pulmonary artery to the right ventricle.
• Mitral valve allows the blood to flow from the lungs into the left atrium. It prevents backward flow from the left ventricle to the left atrium.
• Aortic valve allows the blood to leave the left ventricle through the aorta. The aorta carries the blood throughout the rest of the body. This valve prevents backflow from the aorta to the left ventricle.
• Arteries carry the blood pumped away from the heart
• Capillaries are delicate blood vessels that exist throughout your body. They transport blood, nutrients and oxygen to cells in your organs and body systems. Capillaries are the smallest blood vessels in your vascular system.
• Veins are blood vessels located throughout your body that collect deoxygenated blood and return it to your heart.
• All of the body's components receive oxygen and nourishment from the blood in order to function.
• Blood vessels are channels that carry blood throughout your body. They form a closed loop, like a circuit, that begins and ends at your heart. Together, the heart vessels and blood vessels form your circulatory system.
• The pulmonary artery is an artery that carries deoxygenated blood from the right ventricle to the lungs where gas exchange occurs between the blood and air in the alveoli.
• Pulmonary vein is a vein that carries oxygenated blood from the lungs to the left atrium of the heart.
• The aorta is the largest artery of the body and carries blood from the heart to the circulatory system.
• The inferior vena cava returns de-oxygenated blood from the lower body regions (legs, back, abdomen and pelvis) to the right atrium.
• The superior vena cava returns deoxygenated blood to the heart from the head and arms. 
• Diastole is the relaxation of the heart during which its cavities expand and fill with blood 
• The Systole is the period of contraction of the ventricles of the heart that occurs between the first and second heart sounds of the cardiac cycle