1. The blood circulatory system (cardiovascular system) delivers nutrients and oxygen to all cells in the body. It consists of the heart and the blood vessels running through the entire body. The arteries carry blood away from the heart; the veins carry it back to the heart.
2. Your heart is a muscle, and its job is to pump blood throughout your circulatory system.
3. The arteries (red) carry oxygen and nutrients away from your heart, to your body's tissues. The veins (blue) take oxygen-poor blood back to the heart. Arteries begin with the aorta, the large artery leaving the heart. They carry oxygen-rich blood away from the heart to all of the body's tissues.
4. septum (SEP-tum): The septum is a thick wall of muscle that divides the heart. It separates the left and right sides of the heart.
5. Valves maintain direction of blood flow
Valves maintain direction of blood flowAs the heart pumps blood, a series of valves open and close tightly. These valves ensure that blood flows in only one direction, preventing backflow. ... The mitral valve is between the left atrium and left ventricle. The aortic valve is between the left ventricle and the aorta.
6. Red cells, contain a special protein called hemoglobin, which helps carry oxygen from the lungs to the rest of the body and then returns carbon dioxide from the body to the lungs so it can be exhaled. Blood appears red because of the large number of red blood cells, which get their color from the hemoglobin.
7. White blood cells: White blood cells (also called leukocytes; pronounced: LOO-kuh-sytes) are a key part of the immune system. The immune system helps the body defend itself against infection. Different types of white blood cells (WBCs) fight germs, such as bacteria and viruses .
8. Hemoglobin, Human blood is red because of the protein hemoglobin, which contains a red-colored compound called heme that's crucial for carrying oxygen through your bloodstream. Heme contains an iron atom which binds to oxygen; it's this molecule that transports oxygen from your lungs to other parts of the body.
9. Veins carry blood toward the heart. After blood passes through the capillaries, it enters the smallest veins, called venules.
10. The upper chambers, the right and left atria, receive incoming blood. The lower chambers, the more muscular right and left ventricles, pump blood out of the heart. The heart valves, which keep blood flowing in the right direction, are gates at the chamber opening
