Cardiovascular System
Cardiovascular System - Function The cardiovascular system transports, from one part of the body to another: nutrients, oxygen, ions, proteins, hormones and other signaling molecules, as well as waste products, including carbon dioxide. This system also helps to maintain homeostasis of fluid volume, ph, and temperature. Cardiovascular System - Organs The primary components of the cardiovascular system are blood, the heart, and the vessels of the circulatory system, which work together to transport nutrients, wastes, and gases to every cell in the body. The blood that is circulated throughout the body contains two main components: Plasma contains water, electrolytes, glucose, proteins (including enzymes, hormones, and blood clotting factors) and metabolic wastes Formed elements or blood cells There are three types of formed elements: Red blood cells transport oxygen and carbon dioxide. White blood cells fight infection by attacking foreign cells, and clear old or diseased cells. Platelets are important for hemostasis (not to be confused with homeostasis); hemostasis is our ability to stop bleeding after vascular injury (injury to blood vessels). The blood functions to transport molecules and blood cells and contributes to the maintenance of ph balance. Blood cells are formed in the red bone marrow. The heart is divided into four chambers. The two lower chambers, called ventricles, force blood out into the arteries. The two upper chambers of the heart, called atria, receive blood returning from the veins. The heart contracts as a unit, both atria (named right and left) contract together to
move blood into the ventricles and then both ventricles contract at the same time to move blood out of the heart into the pulmonary artery and the aorta. The cardiovascular system is divided into two functional subsystems. The systemic circuit transports blood and its components to the body. The pulmonary circuit transports blood and its components between the heart and the lungs. Arteries of the systemic circuit (also known as the systemic circulatory circuit) carry oxygenated blood from your heart to provide oxygen and nutrients dissolved in the blood to every cell in your body. When blood leaves the left ventricle it first enters the aorta, the largest artery in the human body. Arteries gradually branch into smaller and more numerous arterioles which then supply blood to the smallest vessels, termed capillaries. It is estimated that your body contains approximately 60,000 miles of capillaries, that is enough to encircle earth three times! Capillaries allow the exchange of oxygen, nutrients and waste between the blood and tissue cells. After waste has been picked up, blood is moved through vessels of increasing size venules into the larger veins. Veins return oxygen-poor blood back to the heart, where the blood is passed to the pulmonary circuit to the lungs to pick up oxygen.
The pulmonary artery (part of the pulmonary circuit) carries oxygen-poor blood from the right ventricle of the heart to the lungs for oxygenation and removal of carbon dioxide. The pulmonary veins carry oxygenated blood from the lungs to the left side of the heart.
Without this system in place that involves both the pumping of the heart to squeeze blood out, and the network of vessels to distribute the pumped blood, the cells of your body would not have an adequate supply of nutrients and oxygen. Cardiovascular System - Anatomy and Direction The heart lies medial to the lungs, anterior to the spinal cord, posterior to the sternum, and superior to the diaphragm. The heart is divided into four chambers. The two lower chambers, called ventricles, force blood out into the arteries. The two upper chambers of the heart, called atria, receive blood returning from the veins.